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 different 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 different data models; shx-index file; xml-meta info file; shp-main 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 – tiff 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=√(𝑎2 − 𝑏 2 )/𝑎 | Second Eccentricity
𝑒
(e) –
| Cartesian Coordinate System – x,y,z | Geographic Coordinate System – longitude, latitude, height;
√1−𝑒 2
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 difficult 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
2
quantities to their true values | Measure of Precision – standard deviation: 𝜎 = ± √Ε𝑣
; v:residuals; n:number of
𝑛−1
observations: 𝜎 2 :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 differences on elevations determined; Differential 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 | Effect of Curvature
– Cf=0.667 M^2=0.0239 F^2; Cm=0.0785K^2| Effect 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),
𝑐
GNSS/GPS | Propagation of Electro-Magnetic Energy – 𝑉 = 𝑓 ∙ 𝜆 ; 𝑉 = (c=299,792,458m/s & n=atmospheric index of
𝑛
𝐶∗𝑡
𝑛𝜆+𝑝
retraction) | 𝐿 =
&𝐿 =
(L=dis; =wavelength; n=num of full cycle; p=length of fractional part) | Total Station 2
2
=EDM+electronic digital theodolite+a computer | Horizontal Distance(H) – d=(elev a + he)-(elev b + hr); H=√𝐿2 − 𝑑2 ; 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 2 + 𝐸𝑟 2 + 𝐸𝑐 2 + (𝑝𝑝𝑚 ∗ 𝑑)2 ) | 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.Computation of preliminary azimuth&bearing 3.departure+latitude computation
4.departure+latitude closure condition (≠ 0) 5.traverse linear misclosure + relative precision (√(𝑑𝑒𝑝 𝑚𝑖𝑠)2 + (𝑙𝑎𝑡 𝑚𝑖𝑠)2 =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 sections; 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 100ft; r-radius; ddegree of circular curve; S=ro-radians | Degree of Circular Curve – chord def: angle @ center of circular arc from cord of 100ft
|Circular Curve Formula – PC-point of curvature; PT-point of tangent; PI-point of intersection; <PI,PC,PT=I/2; <P,PC,PT=B/2 or =C/2;
deflection angle @ P=(B/2+C/2) | Horizontal Curve Equations – L=RI(rad); L=100(I/D)ft; 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 until reach PT | Vertical Curves – crest:neg change
in grade; sag:pos change in grade | Vertical Curves Equation – 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 | Vertical Curve Terms - BVC (Begin of Vertical Curve) / VPC (Vertical Point of Curvature) / PVC (Point
of Vertical Curvature); - EVC (End of Vertical Curve) / VPT (Vertical Point of Tangency) / PVT (Point of Vertical Tangency); - VPI (Vertical
Point of Intersection) / PVI (Point of Vertical Intersection); - 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: Elevation measured from the vertical datum |