GIS | GIS(Geographic Information System) – a system to capture, store, manipulate, analyze, manage, and present spatial or
geographic data | GIScience – academic theory behind development, use, application of geographic information system | First
Law of Geography – everything is related to everything else but near things are more related than distant things (spatial
location) | 5 Compents of GIS – 1. People: you 2. Methods & Procedures 3.m Data: surveying, photogrammetry, laser scanning,
remote sensing 4. Hardware: pc, workstation, smart phone, tablet 5. Software: arc GIS | Word Processor – write document &
deal w/ words on computer | GIS Application/Software – deals w/ spatial info on computer | Geospatial Data – geographic
space so data from di erent sources can be cross-referenced & represented of geographic scale such that the data can be
generalized or symbolized | Basic Element of GIS Data – Location: (x,y) – coordinates or locational reference; z – height or
elevation – Attribute Data: describes the demonstration of location (name, size, owner) | GIS Data Models – 3 ways of
representing geospatial data: 1.Vector: discrete point, lines, polygons, reality is divided to objects defined by their boundaries
(shape+size not regular); 2.Raster: depicts real world by grid of cells w/ spectral or attributes values, embedded space is
divided to cells of regular shape+size; 3.Surface: depict real world by set of points or continuous lines of great values | Vector
Model – Point: a pair of x+y coordinates -Line: a sequence of points – Polygon: a closed set of lines | Raster Data Model – raster
data is based on space tessellation; one grid is one unit(pixel), geographic location is embedded in cells location | TIN
(Triangulated Irregular Network) Model – connect closet points, space divided to triangles, edges only intersect at the original
sample points; input/given: regular or irregular distributed points with obs; output: a network of triangles formed under certain
values; use: represent a surface, terrain; good properties: resolutions of data sets, higher at dense sampling regions | Data
Format – Data type: vector vs raster; File Format: a format for encoding data for storage in computer file | Shapefile (.shp) –
ESRI’s vector data format (closed), consist of multiple files, store di erent data models; shx-index file; xml-meta info file; shpmain shape file; sbx-spatial infex file(fast); sbn-spatial bin file(bonding); prj-map projection file; dbf-dBASE file(attribute) | GML
(Geography Markup Language) – XNL grammar defined by open geospatial consortium to express geographic features | KML
(Keyhole Markup Language) – XML: notation for expressing vector data; KML: international standard of OGC; KMZ: zipped KML
file | GeoJSON – open standard format designed for representing vector data, based on Java Script Object Notation | AutoCAD
– contour elevation plots in AutoCad DXF format | Digital Line Graph(DLG) – USGS(united state geological survey) format for
vector data | Spatialite – spatial extension to SQLite database engine | TIGER – topologically integrated geographic encoding
and refrencing ESRI GRID binary format – proprietary format (binary); 2 folders hold data, info folders shared w/ among grids |
ESRI Grid ASCII format – proprietary format, single file to hold data, bigger in size | GeoTIFF – ti variant enriched w/ GIS meta
data | JPEG2000 – open source vaster format, compressed format, allows both lobby or lossless compression | ENVI format –
flat binar file | BSQ (Band Sequential) format – r1,r2,r3,…,r9,g1,g2,g3,…,g9,b1,b2,b3,…,b9 | BIP (Band Interleaved by Pixel)
format – r1,g1,b1,r2,g2,b2,r3,g3,b3,…,r9,g9,b9 | BIL (Band Interleaved by Line) format – all of these in rows like the grid | File
Name Extensions – GIF: .gif&.gfw; JPEG: .jpg&.jgw; JPEG 2000: .jp2&.j2w; PNG: .png&.pgw; TIFF: .tif&.tfw | Raster Data Format
– IMG:ERDAS imagine image file format; ECW: Enhanced Compressed Wavelet format from ERDAS imagine; DRG:Digital Raster
Graphic-digital scan of paper; MrSID:multi-reason seamless image database | Geodetic Datum – an abstract coordinate
system w/ a reference surface that serves to provide location to being survey + circulate maps | Horizontal Datum – measure
2D position (longitude + longitude) on the surface of earth | Vertical Datum – measure elevation or water depth | Geoid –
gravitational surface, perpendicular to gravity, regular surface, mature naturally | Ellipsoid – mathematical surface obtained by
revolving an eclipse about earth polar axis | Geodetic height (h) – height above ellipsoid | Orthometric height(H) – height
above geoid,elevation | Geoid height(N) – geoidal separation/height | h=H+N | Deflection of the Vertical – angle between the
vertical direction (gravity) + normal to ellipsoid; E -xc = deviation of vertical on median; n-Et = deviation at the vertical on normal
plane | Define an Ellipsoid – a:semi-major axis, b:semi-minor axis, f:flattening(f=(a-b)/a | First Eccentricity (e) – e= (𝑎 − 𝑏 )/𝑎
| Second Eccentricity (e) –
| Cartesian Coordinate System – x,y,z | Geographic Coordinate System – longitude,
√
latitude, height; spherical or geodetic coordinate system for measuring and communicating positions directly on the Earth |
Mercator Projection – use cylinder to touch/wrap or cut the ellipsoid/sphere; distortion: get larger away from equator;
“conformal mapping” | Transverse Mercator Projection – paper touches meridian: central meridian | Indiana State Plane
Coordinate System – transverse Mercator; INW-Indiana West; INE-Indiana East | West Lafayette UTM=16N (60 total)
SURVEYING | Surveying – the science,art,technology of determining the relative position on earth’s surface; discipline encompasses all
methods for measuring+collecting information about the physical earth and environments processing that information dissenciting a varity
of resulting products to wide range of clients; important since beginning of civilization, measuring+markup boundaries of property
ownership, growing demand for variety of maps | Units of Measurement – magnitude of measurements must be given in
specific units; length,area,volume,angle | Length – foot (ft); Conversions: 12in=1ft; 39.37in=1m; 1 US survey ft=0.3048006m;
1in=2.54cm; 1 international ft=0.3048ft; -meter (m); mm=10^-3m; cm=10^-2m; km=10^3m; 1ft=12in; 1yd=3ft; 1in=2.54cm;
1m=39.37in; 1mi=5280ft; 1gunter’s chain=66ft | Area – square ft, yd; acre=10square chain; sq meter, hactare
(10*66^2=43500ft^2) | Volume – cubic ft,yd, acre-ft; cubic meter | Angle – degree ()=1/360; 1=60’; 1’=60”; DMS format
(Degree, Minute, Second); Radian: 2-360 | Significant Figures – 24,0.0020 (2) – 364, 0.00240 (3) – 7261,0.0007621 (4) |
Observation – never exact, contain error, true value never known; assessing the mag of errors in obs. | Direct Observations –
tape to a line, EDM to line w/ total station, protractor to angle, turning an angle w/ total station | Indirect Observations – not
possible to apply a measuring instrument directly to quantity be observed | Errors in Measurements – E=X-𝑋 ; E=errors in
observations; X=observed value; 𝑋 =true value (unknown) | Mistakes – mistakes=observers blunder usually caused by misunderstanding problem -carelessness -fatigue -missed communication -poor judgement; large mistakes are easy to detect;
small mistakes are di icult to detect | Types of Errors – Systematic Error: mathematically modelled+corrected – Random Error:
law of probability, most probable value, residuals; =Observed value – True Value | Law of Probability – small erros occur more
often-more probable; large errors occur less often-less probable; pos + neg errors happen w/ same frequency-equal probable |
Most Probable Value (MPV) – calc if redundant observation have been made; meas in excess of min needed to determine
quantity; MPV=arithmetic mean, avg | General Law of Probability – Residual = MPV-observed value; small residuals occur
more often, large residuals occur less often; pos + neg residuals happen w/ same frequency-equal probable; follows normal
distribution w/ mean of 0 | Precision – degree of refinement or consistency of group observations | Accuracy – absolute
nearness of observed quantities to their true values | Measure of Precision – standard deviation: 𝜎 = ± √ ; v:residuals;
n:number of observations: 𝜎 :variance | Error Propagation – all observations contain errors- all computations contain
observations have errors; propagation of random errors utilizes general law of propagation using variances | Error of a sum of
observations – z=a+b+c+…+n | Errors of a Series – a series of similar quantities w/ similar errors, angles within a closed
polygon; 𝜎𝑎 = 𝜎𝑏 = 𝜎𝑐 = ⋯ = 𝜎 | Error of a Product – Area z=A*B | Leveling - general term applied to any of the various
processes by which elevations of points or di erences on elevations determined; Di erential Leveling: determining elevation;
Profile Leveling: determining configuration of ground surface along reference line | Vertical Line - A line that follows the local
direction of gravity | Level surface - A curved surface that at every point is perpendicular to the local plumb line | Level line - A
line in a level surface | Horizontal plane - A plane perpendicular to the local direction of gravity | Horizontal line - A line in a
horizontal plane | Vertical datum - Any level surface to which elevations are referenced | Elevation - The distance measured
along a vertical line from a vertical datum to a point or object | Geoid - A particular level surface that serves as a datum for all
elevations | Bench Mark (BM) - A relatively permanent object, natural or artificial, having a marked point whose elevation above
or below a reference datum is known or assumed | Vertical control - A series of bench marks or other points of known
elevation established throughout an area | E ect of Curvature – Cf=0.667 M^2=0.0239 F^2; Cm=0.0785K^2| E ect of
Refraction – Rf=0.093 M^2=0.0033 F^2 | Allowable Misclosure – 𝐶 = 0.02√𝑛 & 𝐶 = 2.8√𝑛 | Stationing – relative position on
linear feature | Distance Measurement – distance between 2 points; horizontal distance; ways to measure it: pacing,
odometer, taping, Electronic Distance Measurement (EDM), GNSS/GPS | Propagation of Electro-Magnetic Energy – 𝑉 = 𝑓 ∙
∗
𝜆 ; 𝑉 = (c=299,792,458m/s & n=atmospheric index of retraction) | 𝐿 =
&𝐿 =
(L=dis; =wavelength; n=num of full
cycle; p=length of fractional part) | Total Station - =EDM+electronic digital theodolite+a computer | Horizontal Distance(H) –
d=(elev a + he)-(elev b + hr); H=√𝐿 − 𝑑 ; 𝐻 = 𝐿𝑐𝑜𝑠 ∝= 𝐿𝑠𝑖𝑛𝑧; he=equip height; hr=reflector height; L=slope; d=change in elev;
z=zenith angle | Errors in EDM – Constant Errors (mis-centering error in instrument, rod, EDM error), Scalar Error (PPM for
EDM), Error Propagation of Sum (𝐸𝑑 = √𝐸𝑖 + 𝐸𝑟 + 𝐸𝑐 + (𝑝𝑝𝑚 ∗ 𝑑) ) | Angles – directions=“azmuch” + “bearing”;
1.reference or starting line:back sight; 2.direction of turning:to the right/left; 3.angular distance:DMS/decimal degrees,radians |
Interior Angle – angle inside closed polygon: (n-2)180 | Deflection Angle – an extension of the back line to forward station |
Azimuth – horz. Angle observed CW from reference meridian (N); Range: 0<Az<360 | Bearing – acute horiz angle between
reference meridian and line, either N or S toward E or W (ex. 54-N 54 W) | Magnetic Declination – horiz angle obesv from
geomatic meridian to magnetic north | Traverse – consecutive lines whose ends have been marked whose length and
directions determined | Interior Angle Misclosure - (n-2)180 | Exterior Angle Misclosure – (n+2)180 | Allowable Angle
Misclosure – 𝐶 = 𝐾√𝑛 | Rectangular Coordinates – xb= xa+(departure ab/(xb-xa)) & yb=ya+(latitude ab/ (yb-ya)); Departure:
east/west- 𝐿𝑠𝑖𝑛 ∝; Latitude: north/south – 𝐿𝑐𝑜𝑠 ∝(azimuth) | Steps for Traverse Adjustment – 1.Balancing angles (=total angular
misclosure/# of angles) 2.Computa on of preliminary azimuth&bearing 3.departure+la tude computa on 4.departure+la tude
closure condi on (≠ 0) 5.traverse linear misclosure + rela ve precision ( (𝑑𝑒𝑝 𝑚𝑖𝑠) + (𝑙𝑎𝑡 𝑚𝑖𝑠) =linear mis/total trav length)
6.traverse adjustment 7.adjust azimuth +length (tan,length,dep, lat)|Horizontal Curves – lines on same horiz plane; curves in horiz
plane used to connect 2 straight tangent sec ons; spirals=radius decreases uniformly from ∞ at tangent; r=radius of curvature;
p=curvature-p=1/r | Degree of Circular Curve – arc def: central angle from circular arc of 100 ; r-radius; d-degree of circular curve;
S=ro-radians | Degree of Circular Curve – chord def: angle @ center of circular arc from cord of 100 |Circular Curve Formula – PCpoint of curvature; PT-point of tangent; PI-point of intersec on; <PI,PC,PT=I/2; <P,PC,PT=B/2 or =C/2; deflec on angle @ P=(B/2+C/2)
| Horizontal Curve Equa ons – L=RI(rad); L=100(I/D) ; L=I/D(stat.); R=5729.58/D; T=Rtan(I/2); LC=2Rsin(I/2); E=Ttan(I/4); M=Ecos(I/2)
| Incremental Chord Method – 1.start from PC 2.calc 𝛿𝑎 and Ca 3. Fix 𝛿𝑎 then meas Ca to mark 63+00 4.calc 𝛿64 and C 5. Fix 𝛿64
then meas c to mark 64+00 6. Repeat 4+5 un l reach PT | Ver cal Curves – crest:neg change in grade; sag:pos change in grade |
Ver cal Curves Equa on – rate of change of grade = constant; yp”=2C; yp’=2cx+b; yp=cx^2+bx+a; Y=Ybvc+g1X+cX^2; c=(g2-g1)/2 |
Ver cal Curve Terms - BVC (Begin of Ver cal Curve) / VPC (Ver cal Point of Curvature) / PVC (Point of Ver cal Curvature); - EVC (End
of Ver cal Curve) / VPT (Ver cal Point of Tangency) / PVT (Point of Ver cal Tangency); - VPI (Ver cal Point of Intersec on) / PVI (Point
of Ver cal Intersec on); - g1 : The percent grade of the back tangent; -g2 : The percent grade of the forward tangent; - L: Horizontal
distance from BVC to EVC (Distance from BVC to VPI = L/2, Equal tangent); - Xp: Horizontal distance from BVC; - Yp: Eleva on
measured from the ver cal datum |