CEE 424
GIS for Civil Engineers
Homework 5-Answers
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When asked to print a screen shot, capture the screen and paste it to the
document. Crop the image to show the map only. No need to add any other
elements to the map.
When asked to print a layout, add as much as you can of the following: Your
name, Class #, north arrow, a scale bar, a scale text, and a legend. All are under
“insert” when in layout mode. Shadows and borders can be inserted by
“NeatLine” under “Insert”.
I will ask you to answer several questions at a certain step of the exercise. To
save time, always check at what step should you answer the following question.
Section 5: Analyzing feature relationship
Chapter 13: Projecting Data in ArcMap
13-1 What is “on-the-fly projection” in ArcMAP?
Answer: a temporary projection of data to match the projection of the data
frame it is being added. The changes in coordinates are temporary and apply only
within the data frame.
Exercise 13a: projecting Data for Display
13a-1 After step 14: notice the orientation of the lower 48 states. After step 22: the lower
48 states seem to have rotated, why?
Answer: because the first projection was a cylindrical and the second was a conic. It
might not seem to be rotated, that is OK.
Exercise 13b: Defining a Projection
After step 21: close ArcMap and do not save changes. Start ArcToolbox and change the
projection of the layer: fastCities.SHP to : USA CONTIGUOUS ALPERS EQUAL
AREA CONIC. Start ArcMAP and get to exercise 13b. Now add the layer :FastCities to
the lower 48 states data frame. What happened when you assumed a wrong projection of
the cities map? Print a screen shot.
Answer:
The map is very distorted, some cities are in the ocean!
(NOTE: for quarters after autumn 2010, the cities in the above map are in their correct
positions at this step)
Section 6: Creating and Editing Data
Chapter 14: Building Geodatabases
14-1 What is a “feature class”?
Answer: A feature class is a group of pints, lines, or polygons representing similar
geographic data. All features within a feature class have the same geometry point,
line, or polygons.
14-2 Shapefiles, geodatabases, coverages, and CAD files include feature classes, what
is the difference?
Answer: shapefiles include a single feature class: points, lines, or polygons. The
rest may include more than one feature class.
14-3 Explain the structure of a geodatabase, how the data is stored in smaller units of
data in a manner similar to directories and subdirectories in a DOS structure.
Answer: A geodatabse include feature data sets, the feature datasets include
feature classes that are related and can be treated as one unit. Feature classes
include features that have the same geometry.
14-4 What are the advantages of a geodatabase over the spatial data formats?
Answer:
1. The ability to group feature classes that are related to a single feature
database. Operations can then be performed on all the feature classes
in a feature database at one step.
2. The ability to store point, line, and polygon features in one file.
3. The ability to save labels as annotation feature classes that can then be
added to another map.
4. The ability to create a domain for the attributes
14-5 What is the difference in format between a personal and a multiuser geodatabase?
Answer: Personal database have smaller storage space (such as 2 GB), whereas
multiuser geodatabases have much larger amounts of storage. Personal databases
can be viewed by many, but only edited by one user at a time. Multiuser
geodatabases can be edited by multiple users simultaneously. Personal databases are
stored as Microsoft Access, while multiuser geodatabases are stored as a relational
database management system file: Orcale, Informix, MS SQL Server, or DB2.
Exercise 14a: Creating a personal database
14a-1 After step 18, print the description field of the metadata of the FireHydrants feature
class.
Answer: click the metadata tab, then print.
NOTE THAT THE ABOVE SCREENSHOT COMES FROM ArcGIS 9.3. This will be
different in Arc 10
Exercise 14b: Creating feature classes
14b-1 When you create a feature class, what parameters do you have to define and what
are they made up of?
Answer: parameters to be defined when creating a new feature class are geometry
and spatial reference. Geometry is made up of point, line, or polygons. Spatial
reference is made up of a coordinate system, a spatial domain that describes the
limits or boundaries of the location of the data, and precision to define the smallest
measurement possible within the feature class.
14b-2 If the units of coordinate system of a feature class are miles, what is the smallest
measurement possible if the precision is 63360?
Answer: 1 inch, one mile is 5280 ft, one ft is 12 in.
14b-3 After step 13, print the spatial properties of the metadata metadata for the
WaterLines feature class that you created.
Answer:
NOTE THAT THE ABOVE SCREENSHOT COMES FROM ArcGIS 9.3. This will be
different in Arc 10
Exercise 14c: Adding fields and domains
14c-1 After step 16, launch ArcMap from within ArcCatalog, open a new empty map.
Drag the WaterLines feature class from ArcCatalog to the table of contents of the empty
map in ArcMap. The feature class “WaterLines” is added to the map. Right click on it in
the table of contents of ArcMap and open the its table of attributes. You get and empty
table of attributes, no values are added yet, but you get the fields you created. Print a
screen shot of that table.
Answer:
Chapter 15: Creating features
Exercise 15a: Drawing Features
15a-1 after step 14, print a screen shot.
Exercise 15b: Using feature Construction tools
After step 27, Draw a parcel starting at a corner of which x and y are 1699676 and
321593 (right click on the map and select “absolute x and y”). The parcel shape is a
square of 82 ft side length. The first side is parallel to the northeaster side of parcel 2702.
Print a screen shot similar to the figure below.
Ansawer:
After creating the first point, right click on the northeastern side of parcel 2702 and
click on “parallel”. Right ckick and select “length”, type 82. Right click on the
northeastern side of parcel 2702 and select “perpendicular”. Then right click and
select “length” and type 82. Finally, right click inside the new parcel and select
“square and finish”. You are done. The figure below is the screen shot needed.