Questions: 1. What is the total area (square feet) of land exactly within 175 meters of all the stations? 2. What is the total area (square feet) of land exactly within 175 meters of all the stations per each land-use? 3. What is the total area (square feet) of land exactly within 175 meters of each station per each land-use? • write down the steps required to calculate the areas Question 1: 1. What is the total area (square feet) of land within 175 meters of all the stations? Question 1: 1) Buffer : 175 meters, Buffer_175, ALL 2) Clip: LandParcels as input feature, Buffer_175 as Clip, Output: LandParcels_clip1 3) Add Field: Name: AREA, type: LONG 4) Calculate Geometry : Area - Feet Question 1: Question 2: 2. What is the total area (square feet) of land within 175 meters of all the stations per each land-use? Question 2: There are two ways: i) using Summarize on the Clipped layer that we have created in Question 1 [Summarize LandUse field and make sure to check the SUM of AREA field] ii) Disssolve the Clipped Layer based on LandUse field and Add Layer again and Calculate the geometry. Question 2: Question 3: 3. What is the total area (square feet) of land within 175 meters of each station per each land-use? Question 3: 3. What is the total area (square feet) of land within 175 meters of each station per each land-use? Question 3: 1) Buffer : 175 meters, Buffer_175_N, Dissolve : NONE 2) Intersect: LandParcels and Buffer_175_N 3) Dissolve: base on two conditions: LandUse and Number_ID 4) Add Field and Calculate Geometry Spatial Analysis – Geoprocessing Review I Outline • • • • • • • • Add Field Dissolve Merge Buffer Clip Intersect Union Export Attribute Table Spatial Analysis – Geoprocessing Review I • We will review vector geoprocessing using a series of questions: • How many land parcels are there within LandParcels Layer? • How many different “LandUse” Categories are there ? • 30 polygons – 6 Land Use Category How many Land Parcels 1. Right-Click on Layer > Open Attribute Table 2. By looking at the line of (0 out of 30 Selected) How many Land Use category? 1. Selection > Select By Atributes 2. Select LandParcels then LandUse and Unique Values Unique Values of LandUse How many Land Use category? 1. Selection > Select By Atributes 2. Select LandParcels then LandUse and Unique Values Unique Values of LandUse How many Land Parcels with Commercial Land Use? 1. Selection > Select By Atributes 2. Select LandParcels then LandUse and Unique Values 3. Enter the following Expression: LandUse = 'Commercial' Calculate the AREA of each Land Parcel based on Square Feet Add Field 1. Right-Click on Layer > Open Attribute Table Add Field 1. Right-Click on Layer > Open Attribute Table 2. Click on Table Options > Add Field 3. Select Long Integer as Type- and SQF as Name Add Field 1. Right-Click on Layer > Open Attribute Table 2. Click on Table Options > Add Field 3. Select Long Integer as Type- and SQF as Name Add Field 1. Right-Click on Layer > Open Attribute Table 2. Click on Table Options > Add Field 3. Select Long Integer as Type- and SQM as Name • NOTE: Field Type Add Field – Calculate Area (Geometry) 1. 2. 3. 4. 5. 6. Right-Click on Layer > Open Attribute Table Click on Table Options > Add Field Select Long Integer – SQM Right-Click on SQM Field and select Calculate Geometry Click Yes Select Property : Area and Use Coordinate system of the data source. 7. Select Square Meter 8. Click OK Add Field – Calculate Area (Geometry) Add Field – Calculate Area (Geometry) What is the Average AREA of Land parcels in our study area? Field Statistics 1. Right-Click on SQM Field (column) 2. Click on Statistics Field Statistics 1. Right-Click on SQM Field (column) 2. Click on Statistics Create a Table to show Number of Land Parcels in for each Land Use. Field Summarize • Summarize creates a stand alone table • Finds unique values in a field • Counts how many features/rows with that unique value exists • Summarize can give us the Statistics for each unique value What is the Average AREA of Land parcels in our for each Land Use? Geoprocessing: 1. 2. 3. 4. Setting the Environment Disable Background Processing Make sure to store the Relative Path Save the Map Document Geoprocessing: Setting the Environment 1. Geoprocessing 2. Environments Geoprocessing: Setting the Environment 1. Geoprocessing 2. Environments Dissolve 1 – Simple Dissolve 1. Click Geoprocessing > Dissolve 2. Select LandParcels for Input Features 3. For Output feature Class browse to your folder and save it as Dissolve_1 4. Click OK Dissolve 1 – Simple Dissolve • All features have been dissolved into one polygon feature. Dissolve 2 –Dissolve base on Fields 1. Click Geoprocessing > Dissolve 2. Select LandParcels for Input Features 3. For Output feature Class browse to your folder and save it as Dissolve_2 4. In Dissolve_Field window check LandUse– This time we would like to dissolve our features if they have same land-use 5. Click OK Dissolve 2 –Dissolve base on Fields • All features with same LandUse value (land-use) have been dissolved into ONE feature – accordingly we have 6 features (although a few of them are Multipart Features like Industrial lands with three portions) Dissolve 3 –Dissolve base on Fields 1. Click Geoprocessing > Dissolve 2. Select LandParcels for Input Features 3. For Output feature Class browse to your folder and save it as Dissolve_3 4. In Dissolve_Field window check LandUse– This time we would like to dissolve our features if they have same land-use 5. Uncheck “Create multipart features” 6. Click OK Dissolve 3 –Dissolve base on Fields • Dissolves features based on LandUse if they share a border. Merge 1. Add LandParcels_Extra Layer to your map. We would like to Merge (combine) LandParcels and LandParcels_Extra feature datasets into one single layer called LandParcels_Merge. 2. Click on Geoprocessing > Merge 3. Select LandParcels and LandParcels_Extra layer as Input Dataset. 4. Browse to your folder and save the Output dataset as LandParcels_Merge 5. Click OK Merge • Open table of attributes for LandParcel_Merge. Now we have 37 features combined – 30 features from LandParcels and 7 feature from LandParcels_Extra Buffer 1 – Simple Buffer 1. Turn on your Stations layer. We would like to create a buffer of 175 meters around each station– We have 4 stations with unique ID numbers. The points have been categorized in two Types of A and B. Check the Table of Attributes for Stations layer. 2. Click on Geoprocessing > Buffer 3. Select Stations for Input Features 4. Save your Output feature class as Buffer_1 5. For Distance, select Linear Unit and type 175 and select Meter for your unit. 6. Clcik OK. Buffer 1 – Simple Buffer Buffer 1 – Simple Buffer • ArcGIS will create individual buffer areas for each Station/Point. Each buffer polygon will inherit the attributes of the Station(i.e. Number_ID and Type). Also a field showing the buffer distance has been added to the table (BUFF_DIST) Buffer 2 –Buffer based on Distance in a Field 1. One of the attributes of Stations Layer is Buf_Dis Field. Now we would like to create buffer for each Station based on the value within Buf_Dis field 2. Click on Geoprocessing > Buffer 3. Select Stations for Input Features 4. Save your Output feature class as Buffer_2 5. For Distance, select Field and from drop down menu select Buf_Dis field. 6. Click OK. Buffer 2 –Buffer based on Distance in a Field • ArcGIS will create individual buffer areas for each Station based on the buffer distance within the Buf_Dis field. Buffer 3 –Buffer Dissolve ‘ALL’ 1. Now we would like to dissolve all buffers into one single feature (polygon) – get rid of overlapping areas. 2. Click on Geoprocessing > Buffer 3. Select Stations for Input Features 4. Save your Output feature class as Buffer_3 5. For Distance, select Linear Unit and type 175 and select Meter for your unit. 6. For Dissolve Type select ALL 7. Click OK. Buffer 3 –Buffer Dissolve ‘ALL’ • ArcGIS will create a buffer area for each Stations and will dissolve all the buffers then, accordingly we will have one feature as our buffer polygon. Buffer 4 –Buffer Dissolve ‘LIST’ 1. Here we would like to dissolve the buffer areas (polygons) based on one attribute of Stations which is TYPE of the Stations. 2. Click on Geoprocessing > Buffer 3. Select Stations for Input Features 4. Save your Output feature class as Buffer_4 5. For Distance, select Linear Unit and type 175 and select Meter for your unit. 6. For Dissolve Type select LIST and in Dissolve Field check TYPE 7. Click OK. Buffer 4 –Buffer Dissolve ‘LIST’ • ArcGIS will create buffers for each point and will dissolve them based on TYPE attribute of each polygon, accordingly we will have two features polygon Type A and B. Clip – Using Buffer-1 1. Here we would like to extract those parts of LandParcels that overlay with Buffer_1 layer 2. Click on Geoprocessing > Clip 3. Select LandParcels for Input Features 4. Select Buffer_1 for Clip feature 5. Browse to your folder and save the clip as Clip_1. 6. Click OK • Clipped layer will inherit all the attributes of INPUT FEATURE layer Clip – Using Buffer-1 • ArcGIS will extract LandParcels that overlay with Buffer_1 layer. We will get exactly same result if we clip LandParcels with Buffer_3 layer. Clip – Using Buffer-3 1. Here we would like to extract those parts of LandParcels that overlay with Buffer_3 layer 2. Click on Geoprocessing > Clip 3. Select LandParcels for Input Features 4. Select Buffer_3 for Clip feature 5. Browse to your folder and save the clip as Clip_2. 6. Click OK • Clipped layer will inherit all the attributes of INPUT FEATURE layer Intersect 1. Here we would like to find out the geometric intersection of LandParcels layer and Buffer_1 2. Click on Geoprocessing > Intersect 3. Select LandParcels and Buffer_1 as input features 4. Save the Intersect for your Output Feature Class as Intersect_1. 5. Click OK • Intersect layer will inherit all the attributes of all layers within intersect process (LandParcels and Buffer_1) Intersect Intersect • Intersect layer will inherit all the attributes of all layers within intersect process (LandParcels and Buffer_1) • IMPORTANT NOTE: Beware of overlapping regions. Union 1. Here we would like to find out the geometric union of LandParcels layer and Buffer_1 2. Click on Geoprocessing > Union 3. Select LandParcels and Buffer_1 as input features 4. Save the Intersect for your Output Feature Class as Union. 5. Click OK • Union layer will inherit all the attributes of all layers within union process (LandParcels and Buffer_1) Union Coordinates Systems and Projections Outline • Coordinate Systems and Projections • Geodesy • Geoids • Ellipsoids • Geographic Coordinate Systems • Magnetic North vs. True North • Datums • Projections • Applying Coordinate Systems and Projections Coordinate Systems and Projections • Coordinates define the location, extent and shape of geographic objects. How to pinpoint a location on the surface of the earth? How to pinpoint a location on the surface of the earth? • We are using a pair of coordinate values • We are using a reference system that uses latitude and longitude to define the locations of points on the surface of the earth. How to pinpoint a location on the surface of the earth? • We are using a pair of coordinate values • We are using a reference system that uses latitude and longitude to define the locations of points on the surface of the earth. • This reference system is : Geographical Coordinate System [GCS] Geographical Coordinate System [GCS] • This reference system is : Geographical Coordinate System [GCS] • Longitude and latitude are angles measured from the earth's center to a point on the earth's surface. The angles often are measured in degrees. Geographical Coordinate System [GCS] • By putting latitude and longitude together into what is called geographic coordinate, we can pinpoint a location on the earth’s surface. • Sierra Hall Northridge: 34º 14’ 18’’ N, 118º 31’ 51’’W Geographical Coordinate System [GCS] • How to write latitude and longitude values: 1) Babylonian Sexagesimal System: • Sierra Hall Northridge(with N-S and W-E signs): • 34º 14’ 18’’ N, 118º 31’ 51’’W • Sierra Hall Northridge(with negative - sign): • 34º 14’ 18’’, -118º 31’ 51’’ • (-) sign for Southern (S) and Western (W) hemispheres Geographical Coordinate System [GCS] • How to write latitude and longitude values: 1) Degrees Minutes and Seconds 2) Decimal Degrees • Decimal degrees = dd + mm/60 + ss/3600 • Sierra Hall Northridge • 34º 14’ 18’’=34 + 14/60 + 18/3600 = 34.2983º • - 118º 31’ 51’’= 118 + 31/60 + 51/3600= -118.5308 This is just a sign to show Western hemisphere, not to be included in the calculation for decimal degree. The Graticule • The network / arrangements of parallels and meridians. • Parallels: equally spaced east-west lines drawn on maps. • From parallels which ones have a name? • Equator, tropic of Cancer and tropic of Capricorn • Meridians: set of north-south line that are equally spaced at the equator and converge at the north and south poles. • Prime Meridian? • International Meridian Conference (1884): Greenwich The Graticule • The network / arrangements of parallels and meridians. • It is imaginary on the earth, but is drawn on globes and maps for reference. Components of Geographical Coordinate Systems [GCS] 1. 2. 3. 4. Angular Unit of Measurements Prime Meridian – Equator Spheroid (or Ellipsoid)* Datum* Components of Geographical Coordinate Systems [GCS] 1. Angular Unit of Measurements • Latitude and Longitude: measurements that are relative to the center of the earth 2. Prime Meridian – Equator 3. Spheroid (or Ellipsoid)* 4. Datum* Components of Geographical Coordinate Systems [GCS] 1. Angular Unit of Measurements 2. Prime Meridian – Equator • Define the origins for calculating Latitude and Longitude 3. Spheroid (or Ellipsoid)* 4. Datum* Components of Geographical Coordinate Systems [GCS] 1. Angular Unit of Measurements 2. Prime Meridian – Equator 3. Spheroid (or Ellipsoid)* • Shape of the earth 4. Datum* The earth as an oblate ellipsoid (Spheroid) • The earth rotation about its polar axis, introduces outward centrifugal forces perpendicular to the axis of rotation. • The amount of force varies between zero at each pole to a maximum at the equator. • Centrifugal force = mass x velocity2 x distance from axis of rotation The earth as an oblate Ellipsoid (Spheroid) • The earth is not a perfect sphere but an oblate ellipsoid. Different oblate ellipsoids (spheroid) • Clark 1866 ellipsoid • Was the best fit for North America in the 19th century and was used as the basis for topographic maps produced in Canada, Mexico and the United States (late 18th century to 1970s) • World Geodetic System of 1984 (WGS) – [GRS 1980] • Replaced Clark 1866 ellipsoid in North America and is used as the basis of latitude and longitude on map throughout the world. Ellipsoid Semi-major axis Airy 1830, 6377563.396 Modified Airy 6377340.189 Australian National 6378160 Bessel 1841 (Namibia) 6377483.865 Bessel 1841 6377397.155 Clarke 1866, 6378206.4 Clarke 1880, 6378249.145 Everest (Malay. & Sing) 6377304.063 Everest (Pakistan) 6377309.613 Modified Fischer 1960 6378155 Krassovsky 1940 6378245 GRS 80 6378137 South American 1969 6378160 WGS 72 6378135 WGS 84 6378137 * Internationally recognized ellipsoids. Different oblate ellipsoids (spheroid) Different oblate ellipsoids (spheroid) • The earth is not a perfect spheroid. The earth's surface is not perfectly symmetrical, so the semi-major and semi-minor axes that fit one geographical region do not necessarily fit another one. • The most southerly point on the minor axis (the South Pole) is closer to the major axis (the equator) than is the most northerly point on the minor axis (the North Pole). Earth: the Geoid • Even using a Spheroid the map accuracies will not be perfect because the actual shape of the earth is represented by the Geoid. Earth: the Geoid • Even using a Spheroid the map accuracies will not be perfect because the actual shape of the earth is represented by the Geoid. Earth: the Geoid • Even using a Spheroid the map accuracies will not be perfect because the actual shape of the earth is represented by the Geoid. • The geoid can be described as the shape of the earth would be if there were only seas and no continents. Earth: the Geoid • Even using a Spheroid the map accuracies will not be perfect because the actual shape of the earth is represented by the Geoid. Geoid , a surface of equal gravity (at the point used to define MSL) • This imaginary equal gravity surface doesn’t form a perfect smooth ellipsoid; because the differences in topography and density affect gravity pull. Earth: the Geoid • To achieve a more accurate map, the spheroid is moved until the geoid at the area being mapped corresponds best with spheroid surface. Components of Geographical Coordinate Systems [GCS] 1. 2. 3. 4. Angular Unit of Measurements Prime Meridian – Equator Spheroid (or Ellipsoid)* Datum* • The combination of the spheroid and the location where its center is placed is called a datum. Datum • 1920s – 1980s these control points were surveyed relative to the surface of Clark 1866 ellipsoid; forming North America Datum of 1927 (NAD) • Clark 1866 NAD 27 • By the early 1980s, and development of GRS 80 and WGS 84 ellipsoid, a new horizontal reference datum created, the North American datum of 1983 (NAD 83) • GRS 80 NAD 83 Map Projection • Geometrical transformation of the earth’s spherical or ellipsoidal surface onto a flat map surface. • A systematic and orderly representation of the earth’s grid upon a plane. Map Projection • Projected Coordinate System (PCS) • Defines locations on a flat map based on x,y coordinates Map Projection • During the process of converting the spherical glob into a flat screen , we get distortion. • All projections have distortion. Map Projection Classification • Two approaches commonly used to classify the projection: 1) Based on their geometrical distortion 2) Based on the nature of surface used to construct projection (projection surface) Map Projection Classification • Two approaches commonly used to classify the projection: • Based on their geometrical distortion • Distance • Shape • Direction • area • Based on the nature of surface used to construct projection (projection surface) Map Projection Classification • Two approaches commonly used to classify the projection: 1) Based on their geometrical distortion 2) Based on the nature of surface used to construct projection (projection surface) • A plane • A cone • A cylinder Map Projection Properties 1) 2) 3) 4) Scale Completeness Correspondence relations Continuity Map Projection Properties 1) Scale • The stated map scale is only true along points and lines of tangency Map Projection Properties 2) Completeness • the ability of map projection to show the entire earth Orthographic projection Gnomonic projection Map Projection Properties 3) Correspondence relations • Are there point to point correspondence in a map projection – each point on the earth corresponding to a point on the map projection Map Projection Properties 4) Continuity • Continuous spherical surface must be interrupted at some points or along some line. • These breaks in continuity form the map border on a map projection. Map Projection Classification • Projections categories based on geometric distortion: 1) Equal-area projection: Displays an area at its proper relative size. 2) Conformal projection: preserves shape. 3) Equidistance projection: preserve scale and thus distance. 4) Azimuthal projection (True Direction): maintain accurate directions. Identical tiny circles on the generation globe are projected to a flat map. Polar aspect azimuthal equidistance world project tangent at the pole Projected or Unprojected ? • In GIS your data will be either • Unprojected or • Projected Projected or Unprojected ? • In GIS your data will be either • Unprojected • Unprojected data means that it is simply stored in a defined Geographic Coordinate System (GCS) = Latitude , longitude values in decimal degrees. • Projected • Projected data means that a map projection has been applied to your dataset Map Projection Classification • Projection properties • Equal-area projection: • Mollweide Projection Map Projection Classification • Projection properties • Equal-area projection: • Alber Equal Area Conic Map Projection Classification • Projection properties • Conformal / Orthomorphic projection: Mercator Map Projection Classification • Projection properties • Equidistante projection: projections that preserve linear scale for some part of the map – Polar Azimuthal Equidistant Map Projection Classification • Projection properties • Azimuthal projection (True Direction): preserving the direction azimuth. • Polar Gnomonic Projected Coordinate Systems [PCS] • In ArcGIS , when you project your data , the dataset will have PCS in addition to GCS. • Projected Coordinate Systems have a linear unit of measurement [for example meter or feet]. Projected Coordinate Systems [PCS] • It is extremely important to understand the difference between Define Projection and Project tool in ArcGIS. • The only time you use Define Projection is when your dataset is missing Spatial Reference. Projected Coordinate Systems [PCS] • The only time you use Define Projection is when your dataset is missing Coordinate System [Unknown]. Vector Analysis I • Ratio Policy in ArcGIS • Calculating Centroids locations for polygons • Joining and Relating Tables 1) What is the Total AREA (SQF) of all land parcels? • Use geoprocesing Map Document within Ratio Policy Folder to answer the following question 1) What is the total AREA (SQF) of all land parcels? Question 1) What is the total AREA (SQF) of all land parcels? 1) Add a field [SQF, Double] 2) Calculate Geometry – US SQUARE FEET 3) Statistics : SUM = 9,076,376 Question • Use geoprocesing Map Document within Ratio Policy Folder to answer the following question 2) What is the total AREA (SQF) of land parcels within 90 Yards of Power_Line2? Write down the major steps you have to take to answer this question. 2) Total AREA (SQF) of land parcels within 90 Yards of Power_Line2? • • • • • Select Power_Line2 Buffer : 90 Yards Clip: LandParcels using Buffer Re-Calculate Geometry Statistics : SUM = 2,500,097 1) Total AREA (SQF) of land parcels within 90 Yards of Power_Line2? • Geometry calculation or re-calculation is one of the main functionalities of GIS systems. Question • Use geoprocesing Map Document within Ratio Folder to answer the following questions . 1) To ensure safety and control probable fire, the city has to cut the trees within 90 Yards of Power_Line2. Estimate how many trees must be cut. Explained your initial assumption. 1) Approximate total Number of trees within 90 Yards of Power_Line2? • Attributes [not geometric] can be estimated using Ratio Policy method in ArcGIS • Ratio Policy method assumes that the attribute is distributed equally within our region. RATIO Policy • RATIO POLICY AREA: 1000 sqf AREA: 500 sqf Population: 500 Population: 250 1) Approximate total Number of trees within 90 Yards of Power_Line2? • To apply Ratio Policy: Make Feature Layer of the layer that contains the attribute in question [e.i. Number of tree] If you create a feature layer of LandParcels, and check the Ratio Policy for a field {N_Trees} all feature classes that will produce using this layer will have the correct ratio (number) for N_Trees. 2) Approximate total Number of trees within 90 Yards of Power_Line2? 2) Approximate total Number of trees within 90 Yards of Power_Line2? 2) Approximate total Number of trees within 90 Yards of Power_Line2? 2) Approximate total Number of trees within 90 Yards of Power_Line2? 2) Approximate total Number of trees within 90 Yards of Power_Line2? 2) Approximate total Number of trees within 90 Yards of Power_Line2? 2) Approximate total Number of trees within 90 Yards of Power_Line2? Question • Use geoprocesing Map Document within Ratio Folder to answer the following questions. 2) Approximate number of people [ population ] living within ONE mile of HWY 5 in California. Calculate Polygons’ Centroids • In mathematics and physics, the centroid or geometric center of a two-dimensional region is, informally, the point at which a cardboard cut-out of the region could be perfectly balanced on the tip of a pencil (assuming uniform density and a uniform gravitational field). Calculate Polygons’ Centroids • Find the centroid of polygons : • Feature to Point Tool • http://desktop.arcgis.com/en/arcmap/latest/tools/datamanagement-toolbox/feature-to-point.htm Database Management & Geodatabases Attribute Data • Use to capture non-spatial aspects of an entity. • Most often contained in a table • Attributes can be categorized as – Level of measurement • Nominal: Provide descriptive info. Ex. Color, names, types of soil. No implied order, size of quantity. • Ordinal: Imply rank order or scale. Does not represent differences in scale. Ex. Descriptive (short, medium, long) or numeric (1-100). • Interval/Ratio: Where both order and absolute differences in magnitude are represented. Ex. Length, weight, height or depth. Attribute Data • Use to capture non-spatial aspects of an entity. • Most often contained in a table • Attributes can be categorized as – Level of measurement • Interval/Ratio: Where both order and absolute differences in magnitude are represented. Ex. Length, weight, height or depth. • Interval measurement has a an arbitrary starting point instead of an absolute zero (Celsius temperature) Database in Computers • Structured collection of information or • Collection of files • Ordered • Organized Database in Computers • • • • Tables Records Fields Keys Database in Computers • • • • Tables Records Fields Keys Database Management System (DBMS) • DBMS (Database Management System): • A specialized computer program for organizing and manipulating data Database Management System (DBMS) • DBMS (Database Management System): • A specialized computer program for organizing and manipulating data Database Management System (DBMS) • DBMS (Database Management System): • A specialized computer program for organizing and manipulating data • Note: A database is the organized collection of data, often created or manipulated with the help of a DBMS. The terms Database and DBMS should not be used interchangeably. Database Components • Data definition language • Define the structure of the database • Data manipulation language • Manage and retrieve information in the database Functions of Database • • • • • • Define the structure of the database Insert data Delete data Modify data Inquiry about data Join/Relate Tables Non-Relational Database – Flat Files Relational Database Relational Database • Advantages: • • • • Reduces redundancy Allows for dynamic queries Uses SQL (structured query language) Good security Relational Database – Table Relationship • One-to-One Relationship Relational Database – Table Relationship • One-to-Many & Many-to-One Relationship Joining and Relating Tables • Joining Tables: Appends the attributes from one table onto another based on a field (key) common to both. Joining and Relating Tables • Joining Tables: Appends the attributes from one table onto another based on a field (key) common to both. • FIPS – Federal Information Processing Standard Joining and Relating Tables • Relating Tables: Defines a relationship between two tables - also based on a common field (key) - but doesn't append the attributes of one table to the other. Instead, you can access the related data when necessary. Joining and Relating Tables • Tables are linked through Keys. • Keys are items or fields that meet certain requirements (data format and length) and are used to index the records. • Note: Misspelling or spaces in key values can create problems with your join or relate process. • Example: Northridge vs Nothridge or NewMexico vs New Mexico. Joining and Relating Tables • To obtain info about a key field, go to Layer Properties and click on the Fields tab. Joining and Relating Tables • After joining a table, you can preserve the join by right-clicking on the shapefile or feature class and selecting Data…Export Data. Geodatabase • The geodatabase is a container for storing spatial and attribute data and the relationships that exist among them • Format introduced by ESRI with ArcGIS® software • Primary format we will be working with in this class. Geodatabase • The geodatabase is a container for storing spatial and attribute data and the relationships that exist among them • Format introduced by ESRI with ArcGIS® software Geodatabase • Geodatabases can consist of: • Feature Datasets • Feature Classes • Annotation Feature Classes • Raster Datasets • Nonspatial Tables Types of Geodatabase • Personal Geodatabases: Stored within Microsoft Access. Holds up to 2 GB of data. • File Geodatabases: Stored as folders in a file system. Each dataset holds up to 1 TB of data. Fast performance, less restrictive editing locks and supported by many platforms. • ArcSDE Geodatabases: Stored in a relational database using Oracle, Microsoft SQL Server, IBM DB2, or IBM Informix. Requires the use of ArcSDE software. Unlimited in size and numbers of users. Geodatabase Behavior Schemas • A schema defines the physical structure of the geodatabase along with the rules, relationships, and properties of each dataset in the geodatabase. • Users often share their schemas with others. • http://support.esri.com/en/downloads/datamodel Geodatabase Behavior Domains • A list or range of valid attributes for an attribute that limits values. Helps to limit user error. • Range Domains • Example: Pipe diameter (range = 1-5 feet) • Coded Value Domains • Example: Vegetation Type (Tree, Scrub or Grass). ArcGIS TIPS • Creating a Geodatabase • In ArcCatalog: • Navigate to the folder you want to create the GDB in. • Right click and select New… • Select either File or Personal Geodatabase. • Right-click on or in the GDB to create new feature datasets, classes or tables. • You can import your shapefile in geodatabase ArcGIS TIPS • Add Field and Calculate Field Demonstration Ratio Policy in ArcGIS Question • Use geoprocesing Map Document within Ratio Folder to answer the following question: 1) To ensure safety and control probable fire, the city has to cut the trees exactly within 90 Yards of Power_Line2. Estimate (approximate) how many trees must be cut. Explained your initial assumption. Ratio Policy • allows attributes that are involved in splitting (like intersection or clip) to have their values change relative to the area that they represent. Selecting RATIO means the attributes of the resulting features are a ratio of the original feature's value. • The ratio is based on the ratio in which the original geometry is divided. If the geometry is divided equally, each new feature's attribute gets one -half the value of the original object's attribute. RATIO Policy • RATIO POLICY AREA: 1000 sqf AREA: 500 sqf Population: 500 Population: 250 Ratio Policy • The underling assumption in Ratio Policy is that the attribute at hand has an equal spatial distribution within the area. • Process: 1) Make Feature Layer [add _RP to the name of the new layer} 2) Select the attribute that you would need the ratio policy to apply 3) Create a new Ratio Policy layer 4) Use the new Ratio Policy layer in your splitting geoprocessing like Clip or Intersect. 1) Estimate number of trees exactly within 90 Yards of Power_Line2? • Geometry recalculation adds to the complexity of the process and is the source of confusion for GIS analysts. 1) Estimate number of trees exactly within 90 Yards of Power_Line2? • Geometry recalculation adds to the complexity of the process and is the source of confusion for GIS analysts. • If you create a layer of LandParcels, and check the Ratio Policy for a field {N_Trees} all feature classes that will be produced using this layer [in clip or intersect] will have the ratio (number) for Trees. • This ratio will be based on the size of the output geometry. 1) Estimate number of trees exactly within 90 Yards of Power_Line2? • Make Feature Layer 1) Estimate number of trees exactly within 90 Yards of Power_Line2? 1) Estimate number of trees exactly within 90 Yards of Power_Line2? 1) Estimate number of trees exactly within 90 Yards of Power_Line2? 1) Estimate number of trees exactly within 90 Yards of Power_Line2? 1) Estimate number of trees exactly within 90 Yards of Power_Line2? 1) Estimate number of trees exactly within 90 Yards of Power_Line2? 1) Estimate number of trees exactly within 90 Yards of Power_Line2? Question • Use geoprocesing Map Document within Ratio Folder to answer the following questions. 2) Approximate number of people [ population ] living exactly within ONE mile of HWY 5 in California. Spatial Analysis – Vector Data Outline • Selections : • Select By Attribute • Select By Location • Vector based Reclassification Selection By Attribute: Attribute Query • Identifying or select a subset of features [or Table Record] that meet one or several conditions or criteria. Selection By Attribute: Attribute Query • Identifying or select a subset of features [or Table Record] that meet one or several conditions or criteria. • To do so we will need to build Query Expressions • Query expressions in ArcGIS adhere to standard SQL expressions. Selection By Attribute: Attribute Query • Identifying or select a subset of features [or Table Record] that meet one or several conditions or criteria. • To do so we will need to build Query Expressions • Query expressions in ArcGIS adhere to standard SQL expressions. Selection By Attribute: Attribute Query SELECT * FROM forms the first part of the SQL expression and is automatically supplied for you. Selection By Attribute: Attribute Query SELECT * FROM forms the first part of the SQL expression and is automatically supplied for you. Query expressions use the general form that follows a Select * From <Layer or dataset> WHERE: Selection By Attribute: Attribute Query Query expressions use the general form that follows a Select * From <Layer or dataset> WHERE: Select all Features within this Layer which meet the following condition(s) Selection By Attribute: Attribute Query • Here is the general form for ArcGIS query expressions: <Field_name> <Operator> <Value or String> • For compound queries, the following form is used: <Field_name> <Operator> <Value or String> <Connector> <Field_name> <Operator> <Value or String> ... • Optionally, parentheses () can be used for defining the order of operations in compound queries Selection By Attribute: Attribute Query – Relational Operators • Relational Operators • Selection conditions are formalized using Relational Operators: • Less than < • Greater than > • Equal to = • Lass than or equal <= • Greater than or equal >= • Not equal to <> Selection By Attribute: Attribute Query – Relational Operators Selection By Attribute: Attribute Query – Boolean Operators • Boolean Operators • Use OR, AND and NOT to select features. • Most often used to combine Relational conditions and create compound spatial selection. Selection By Attribute: Attribute Query – Boolean Operators • Boolean Algebra • AND operator requires conditions on both sides of the operation be ‘true’ - typically decreases selection sets. Selection By Attribute: Attribute Query – Boolean Operators • Boolean Algebra • OR operator requires only one condition be ‘true’ - typically increase or add to selections. • NOT is a negation operation. i.e. select records that do not equal a specified condition. Selection By Attribute: Attribute Query – Boolean Operators • Boolean Algebra • OR operator requires only one condition be ‘true’ - typically increase or add to selections. • NOT is a negation operation. i.e. select records that do not equal a specified condition. • You must use NOT in front of, BEFORE the condition that you would like to negate. Selection By Attribute: Attribute Query – Boolean Operators Selection By Attribute: Attribute Query • Select by Attributes • To preserve the result of a query you can: 1. Temporarily Save the Selection: Right click the layer and choose Selection… Create Layer from Selected Features. 2. Permanently Save the Selection: Right-click the layer and choose Data… Export Data (Saves to a new shapefile or feature class). Selection By Attribute: Attribute Query - Using LIKE in a query • Use the LIKE operator (instead of the = operator) to build a partial string [TEXT] search. • % means that anything is acceptable in its place: one character, a hundred characters, or no character. • Alternatively, if you want to search with a wildcard that represents one and only one character, use _. Selection By Attribute: Attribute Query - Using LIKE in a query Selection By Attribute: Attribute Query - Using IN in a query • Use IN within your query expression to selecting multiple values from the attribute table [one field] • What is the population of the following zipcodes: Selection By Attribute: Attribute Query - Using IN in a query • What is the population of • the following zipcodes: Selection By Attribute: Attribute Query - Using BETWEEN in a query • Use the BETWEEN operator to select features based on a given interval of an attribute. In this case the interval is INCLUSIVE. • How many zipcodes are there with population more than or equal to 13046 and less than or equal 15000? Selection By Attribute: Attribute Query - Using BETWEEN in a query How many zipcodes are there with population more than or equal to 13046 and less than or equal 15000? Selection By Attribute: Attribute Query • • • • • • • Select the State that its NAME is “California” Select the States that their AREA is greater than 150,000 sqMiles Select the States that their NAMEs starts with letter ‘C’ Select the State that its NAME is “Texas” Select the State that its NAME is NOT “Texas” Select the States that their AREA is greater than or equal 100,000 sqMiles Select the States that their AREA is greater than or equal 100,000 sqMiles with population density greater than 50 • Select the States that their AREA is greater than or equal 100,000 sqMiles OR the states with population density greater than 50 • Select the States that the SECOND letter in their name is ‘a’ Select the State that its NAME is “California” Select the States that their AREA is greater than 150,000 sqMiles Select the States that their NAMEs starts with letter ‘C’ Select the State that its NAME is “Texas” Select the State that its NAME is NOT “Texas” Select the States that their AREA is greater than or equal 100,000 sqMiles Select the States that their AREA is greater than or equal 100,000 sqMiles with [AND] population density greater than 50 Select the States that their AREA is greater than or equal 100,000 sqMiles OR the states with population density greater than 50 Select the States that their AREA is greater than or equal 100,000 sqMiles OR the states with population density LESS THAN OR EQUAL than 50 Select the States that their AREA is greater than or equal 100,000 sqMiles OR the states with population density greater than 50 Select the States that the SECOND letter in their name is ‘a’ Select By Location • Spatial Selection Operation / Proximity Functions • Types of proximity questions: 1. 2. 3. 4. How close are schools to an oil refinery? What neighborhoods are far from convenience stores? Which homes will be affected by freeway noise? How close are the nearest competing businesses? Select By Location • Spatial Selection Operation / Proximity Functions • In GIS you can select geographical features not only by their attributes but by their relative locations to other features. We call this operation Select By Location. Select By Location • ArcMap lets select features in one layer based on their location relative to the features in another layer. These relationships include intersection, proximity and containment. Select By Location - Intersection • Intersect returns any feature in Target Layer that either fully or partially overlaps the Source Layer. • How many zipcodes Venice Blvd. is passing through? Select By Location - Proximity • In ArcMap we can select features based on their proximity (distance) to other features. This can be done by using “Are within a distance of” spatial relationship method in ArcGIS. • How many stations are within 100 meters of Power_Line 1? Select By Location - Containment • Sometimes in spatial analysis we have to select features that are within another feature(s). These types of selections are done based on containment spatial relationship. In ArcMap you can select features using “Are completely within” spatial selection method. • How many stations are completely within commercial landuse? Classification • Classification will categorize geographic objects based on a set of conditions. • Classification may add to or modify the attribute data for each geographic object. • Group objects for display or map production. • Assignment from an existing set of classes to a new set of classes. ADD XY DATA • Adding point based on their Geographical Coordinates • • Latitude Longitude ADD XY DATA : GCS • • Locations Table contains Geographic Coordinates of 10 points. X Field contains Longitude values and Y Field contains Latitude values. • These Longitude and Latitude values are based on NAD 83 ADD XY DATA : GCS • • Locations Table contains Geographic Coordinates of 10 points. X Field contains Longitude values and Y Field contains Latitude values. • To map these location we can • • Add a base map Use Add XY Data Function ADD XY DATA : GCS • It is extremely important to remember that the Description value is the Coordinate System of the Input Values [Coordinates of the Points]. ADD XY DATA : GCS • ArcGIS initial Description of the coordinates of the input data is WRONG. We must set the description to a GCS, NAD 83. ADD XY DATA : GCS • ArcGIS initial Description of the coordinates of the input data is WRONG. We must set the description to a GCS, NAD 83. • We have to Edit the Description and Select NAD 83 from GCS. ADD XY DATA : GCS • ArcGIS initial Description of the coordinates of the input data is WRONG. We must set the description to a GCS, NAD 83. • We have to Edit the Description and Select NAD 83 from GCS. ADD XY DATA : GCS • GCS NAD 83 is the correct description of the coordinates of our points. ADD XY DATA : PCS • Using same logic we can map points with projected coordinate system. • Crime_SCV Table presents crime data reported in Santa Clarita Valley in 2012. However, the X and Y coordinates in this case are given in the following Coordinate System: NAD_1983_StatePlane_California_V_FIPS_0405_Feet WKID: 2229 Authority: EPSG Geocoding • The process of creating Map Features [ for example points ] from addresses is called geocoding. Geocoding • The process of creating Map Features [ for example, points ] from addresses is called geocoding. • Geocoding Addresses requires : 1. Address Table: a table containing the list of addresses you want to geocode. 2. Street-Level Reference data: A feature class [line] containing street names, street type and so on 3. Address Locator: a file that contains reference data and “geocoding rules” Geocoding • Output of Geocoding is either: • Shapefile • Geodatabase feature class Geocoding • Create a new Address Locator in ArcCatalog Geocoding • Select Address Locator style as Dual Range Geocoding • Select Roads feature and save the locator ADD XY DATA • Adding point based on their Geographical Coordinates • • Latitude Longitude ADD XY DATA : GCS • • Locations Table contains Geographic Coordinates of 10 points. X Field contains Longitude values and Y Field contains Latitude values. • These Longitude and Latitude values are based on NAD 83 ADD XY DATA : GCS • • Locations Table contains Geographic Coordinates of 10 points. X Field contains Longitude values and Y Field contains Latitude values. • To map these location we can • • Add a base map Use Add XY Data Function ADD XY DATA : GCS • It is extremely important to remember that the Description value is the Coordinate System of the Input Values [Coordinates of the Points]. ADD XY DATA : GCS • ArcGIS initial Description of the coordinates of the input data is WRONG. We must set the description to a GCS, NAD 83. ADD XY DATA : GCS • ArcGIS initial Description of the coordinates of the input data is WRONG. We must set the description to a GCS, NAD 83. • We have to Edit the Description and Select NAD 83 from GCS. ADD XY DATA : GCS • ArcGIS initial Description of the coordinates of the input data is WRONG. We must set the description to a GCS, NAD 83. • We have to Edit the Description and Select NAD 83 from GCS. ADD XY DATA : GCS • GCS NAD 83 is the correct description of the coordinates of our points. ADD XY DATA : PCS • Using same logic we can map points with projected coordinate system. • Crime_SCV Table presents crime data reported in Santa Clarita Valley in 2012. However, the X and Y coordinates in this case are given in the following Coordinate System: NAD_1983_StatePlane_California_V_FIPS_0405_Feet WKID: 2229 Authority: EPSG Question: • We would like to create a choropleth map of land parcels, showing number of pollution-gauging stations within each parcel. What should we do? Spatial Join Spatial Join • Joins attributes from one feature to another, based on the spatial relationship. Spatial Join : Points to Polygons • Joining Points to Polygons: • A Count_ field will be added to the polygon feature class, showing number of points that fall inside each polygon Question: • Is it possible to get more information from the Station_Pullotion layer rather than just total number of points or Stations? Spatial Join : Points to Polygons • Joining Points to Polygons: • A Count_ field will be added to the polygon feature class, showing number of points that fall inside each polygon • We can get more properties of point layer by checking the “Summarized Attribute Check boxes” Spatial Join : Points to Polygons • Joining Points to Polygons: • We also have the option to create a polygon feature class and give each polygon all the attribute of the point which closest to its borders • A “Distance” field will be created to show the distance between the point and the polygon border. • A distance of zero mean that the point falling inside the polygon is closest to its border. Spatial Join : Points to Lines • Joining Points to Line: • We can use spatial join and join a set of pints to a line or a set of line to get the attributes of the closet point to the line. • A “Distance” field will be created to show the distance between the point and the line. • A distance of zero mean that the point is located on the line. Question: • What is the total area (SQUARE FEET) within 175 meters of all the stations per each land-use? • write down the steps required to calculate the areas Question: • Apply the process and write down the areas for each Land-Use: • • • • • • Commercial Government Parks Residential Industrial Waterbody Question: 1) Buffer : 175 meters, Buffer_175, Dissolve ALL 2) Clip: LandParcel, Buffer_175 as Clip, Output: LandParcel_clip 3) Dissolve: Lanparcel_clip, based on LandUse, Output: Final 4) Add Field: named SQF, Double 5) Calculate Geometry : Area based on SQF Spatial Analysis – ModelBuilder Outline • What is a model? • What is ModelBuilder? • Why use a model? • Element Symbols • How to use ModelBuilder What is a Model? • A model is a collection of geoprocessing operations that automatically execute in sequence to produce a final output dataset. • Any geoprocessing operation in a model can be modified, then the model can be run again to quickly refine an analysis or produce new data that supports an alternative ("what if?") scenario. What is a Model? • A model is represented by a diagram that shows all the processes and the sequence in which they run. The connecting arrows show how elements and processes are related to each other. Example • DEM Processing What is a ModelBuilder? • ModelBuilder is an application that you can access through ArcCatalog or ArcMap in which you create, edit and manage models. • The building block of a model is called a process. A process consists of a geoprocessing tool. • When displayed graphically in a model, the individual parts of a process are called elements. What is a ModelBuilder? Model elements can be in one of three states: • • white elements are Not Ready to Run • colored elements are Ready to Run • elements with a dropshadow have finished running. Has Been Run Why Use ModelBuilder? • Models provide a big-picture view of a project. • Models are reusable. • Processes run seamlessly and faster. • Processes can be run individually. • Models make managing intermediate data easy. • Models can be shared. 1. Creating a ToolBox 1. Open ArcCatalog and browse to your Week_01 folder. 2. Right-click in a white area and click New > Toolbox 3. A Toolbox will be added to your folder 2. Setting the Environment • Now open ModelBuilder.mxd map document with ArcMap. • Click on Geoprocessing > Environments • Set the Current and Scratch workspace to point to your Exercise_Data.gdb and Click OK. 3. Setting the Environment • Click on ModelBuilder Window icon to open ModelBuilder Window. • You can save your model later as GeoProcessing_1 within your Toolbox. An ArcGIS model can be saved in a Toolbox. Click on Save button in Model Window and browse to your Toolbox, save it as GeoProcessing_1. ModelBuilder Toolbar Using ModelBuilder • Drag tools from the appropriate toolbox into the model. • Double-click on the tool and fill in the appropriate parameters. • When created properly the elements will turn the appropriate color: • • • blue = input layer yellow = tool green = output layer 4. Building the Model • You can search for geoprocessing tools in Search Tab. Then you can drag the tool to the Model Canvas. • Search for Buffer tool then drag it to the canvas. 4. Building the Model • You can search for geoprocessing tools in Search Tab. Then you can drag the tool to the Model Canvas. • Search for Buffer tool then drag it to the canvas. • Buffer tool has one input dataset / feature. You can drag Stations layer to the tool or open then tool by double clicking on it and set the input feature to Points layer. • Set the output feature as Buffer_175 4. Building the Model • You can search for geoprocessing tools in Search Tab. Then you can drag the tool to the Model Canvas. • Search for Buffer tool then drag it to the canvas. • Buffer tool has one input dataset / feature. You can drag Points layer to the tool or open then tool by double clicking on it and set the input feature to Points layer. • Set the output feature to Buffer_175 • The Model is not ready to run yet , the buffer distance is missing. Set the buffer distance to 175 Meters. 5. Building the Model • Add Clip tool to the model. • Clip tool has two input dataset. Input Feature and Clip Feature. • Set input feature to LandParcels layer and Clip Feature to the output layer of Buffer tool. 6. Building the Model • Now we have to add Dissolve tool. • Make sure the input of dissolve is LandParcels_Clip Feature and Check LandUse in the Dissolve_Field . • Call output feature Final. 7. Building the Model • Add “Add Geometry Attributes” to the Model Canvas. • Save the model. Open a Saved Model • To open a saved model, click on Catalog Tab in ArcMap. • Browse to your toolbox and open the toolbox. • Right-Click on your model and click Edit Run a Model • Running a Save Model: 1) You can run a model within your model window. You have to browse to your toolbox and click edit to open your model window. Click RUN button to run your model. 2) You can run your model as a tool. Browse to your tool box and click open. The dialog of your tool will open then click OK. Remove DropShadow • A Model with dropshadows is model that “Has been Run”. • To remove the drop shadows, validate the entire model by clicking the Validate Entire Model button on the ModelBuilder toolbar. • Validate reset the Model to “Ready to Run” state. Question: • What if we change the model in such a way that the model asks for buffer distance, instead of hardcoding the distance in the model? Model Parameters • Parameters in model can be defined and selected by users. They create a much more interactive environment when running your tool • Any variable in the model [ distance for example ] can be set as the model parameter. It means that if you run the model as a TOOL the model will ask for its value. 8. Making Model Parameter • We would like to make Distance within Buffer tool a Model Parameter. Distance is a Tool Parameter. • Right-click on Buffer tool, then Make a Variable > From Parameter > Distance • This will expose Distance as a model variable. 8. Making Model Parameter • Right-click on the Variable that you just made and click Rename. Rename the variable to just Distance. 8. Making Model Parameter • Right-click on the Variable that you just made and click Rename. Rename the variable to just Distance. • Right click on Distance variable and click Make a Parameter. This will make that variable a Model Parameter, and if you run the model as a tool the tool will ask for its value. • NOTE: Make sure Distance variable has no values in its field. 9. Run the Model As a Tool • Double-click on your model. • Enter 175 for distance field and click OK to run the model. Intermediate Data • When you run a model, output data is created for each process in the model. • Some of the data created is of no use after the model is run since it was only created to connect to another process that creates new output - intermediate data • Right_Click on output and check for intermediate data Variable Substitution • We can use the value of Distance variable to create the name for our final output feature. • In Model builder you can use in variable in different places using Variable Substitution. • You can put the name of the variable between % signs to use it in other places [ %Distance% ] 10.Variable Substitution • Now we would like to create our final feature and include the buffer distance in its name. For example if the buffer distance is 175 meter, the name of our output will be Final_175 • In your model, double-click on Calculate Area to open its dialog. Call the Output Feature Class Final_%aName%