GRG 360G Exam # 1 Study Guide Lectures: 1 - 9Lecture 1 (August 28th)What is GIS?- Spatially referenced data, some indication of location, could also be relative- Data modelsLocation mattersA place can be explored/studied better to understand what happened at the placeDescribing locationGeographic vs. Spatial- Geographic- geographic location, earths coordinates (geocoding)- Spatial- relative or not tied to earths location- Not all spatial data is geographic but all geographic data is spatial- AutoCAD-> spatialGeography problems- Involves any aspect of location used in info to solve it or as a result- Maps-> you either answer with it or use it to answer a problemWhy GI is special- Multidimensional - Spatial scales- 2 different ways- Must often be projected, latitude and longitude are spherical coordinates you would convert them to UTM- You measure distances by Pythagorean theorem and so only work with planarBig Data- Volume of data, the way it is generated, and its scale- Its being collected passively and cant apply normal/standard methods of analysisSpace usage- Location-> (x,y) coordinates and time zones- Twitterology-> real time (pro) real big noise/time ratioLecture 2 (September 2nd) History of GISOverlay analysis-What this class will focus on -We will have an overlay of data showing different context of same landscape-What should be consistent?oScale- has to be consistentoEach data has to be represented by one object (points, grid, etc)oEach layer only represents one thing (elevation, zoning, streets, etc..) oCovers same area-Can ask, "Which parcels are within the 100 yr. floodplain?"oOverlay levels are parcels and elevation levelsBattle of Yorktown- historical manual overlay (1781) Cholera- found how cholera was spread using overlay analysis (cholera epidemic)Ireland railroad- where to build it using overlayRemote sensing- measuring stuff indirectly-Started with aerial photography oUsed for birds eye viewoGives a synoptic layout of a townoUsed for battle reconnaissance efforts-1860s U.S. Civil War- balloon surveillance used to show enemy positions oKite aerial photography-Used to assess damage from 1906 earthquakeoPigeons used for photography they came and returned with photos oEarly 1900's first aerial photograph -1908-1909 wright brothers-Photogrammetry- making measurements from photographyOverlay (manual)-First described by Jacqueline Tyrwhitt in 1950s -Ian Mcharg-used blacked out transparent overlays and wrote Design With Nature 1960s (manual overlay) paid attention to soil, geology, population, etc.-Doesn’t have to be black and white it can be based on different colors using suitability analysisPhysiographic determinism- builds something in accordance with nature around you Quantitative Revolution-1960s-Because of availability of computers shift from descriptive (qualitative) work to quantitative dataoCould do comparisons and get more data on many places compared to going to one place and getting one set of dataRoger Tomlinson- father of GIS developed CGIS (Canada)Key Ideas-You need to scan in a map and vectorize it-Want to be able to treat an area of soil as a object polygons-Find areas of polygons-Need objects (points, lines, grid cells) and attributes -Use data as layers-GIS developed at Harvard SYMAP 1966-General mapping of data but low quality density of symbols used1961-Environmental systems resource institute ESRI later ARCinfo was formed1970s-1980s government research and development-Military datum to measure Earths surface in order to send missiles to right place-Also GPS was expanded because of military-DIME for spatial analysis for census used x, y coordinatesLecture 3 (September 4th)Military use-GPS and accuracy-Geocoded census- when you plug in an address and get an x, y location Tiger-DIME precursorTopology-Explicit information on spatial relationship-Model points lines and polygons-Share coincident geometry1 24 3Relationship between oak st. and block 1?You put in a direction and store it so that left and right are not relativeRS Landsat (1972) -Studies and monitors planet's landmasses -Shows changes in land cover over time -NASA has a Landsat scienceIncrease in computer abilities always helps GIS data treated as spatial object (cgis) GiScience, Systems, Studies-Accuracy-Effective maps-Location based systems (LBS) and interaction with environment (foursquare)Ch3Time location mapsSelected aspects of the real world -You need to include what you think is importantoWhat to represent (elevation)oHow to represent it (grid cells)oScale and how to break down borders in fractalsoMust fit in geographic concepts-Austin near Dallas, in Texas, adjacent to MexicooThese are formulated through data modelsOntologies- frameworks that we use for acquiring knowledge of the world-Classes-hierarchical-Constraints (properties/attributes)-Relationships among concepts and class-Instances of concepts and classRepresentations-Real worldoHouse-Feature of a real world oMap object-The feature on a mapoMap object-Grid, polygon, point-Then you go to x,y, gridoData structureLecture 4 (September 9th)Last time we developed a map of space Used points, polygons, lines, and areas-First need to decide on a method of data collectionoCensus- method of counting everything oSampling- finite amountoRemote sensingoObjects are measuredoDecide how to represent themA map should only have needed information therefore it is a cut down version of what you imagine when you think of in your imagination Transferring what we imagine to data in the computer-Instead of using base 10 we use base 2 (binary numbers)oAre stored in form of arrays of switches (0 or 1) and are turned on (1) or off (0)oSwitches are grouped in packages of 8 and are called a byte-Bytes group to make a computer word-Words grouped together to make a record-Records grouped together to make a file-5 in decimal=101 in binary2^2 2^1 2^01 0 12^2+2^0=4+1=5-One byte = 256 combinations, so 11111111 binary = 256 in decimal2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^01 1 1 1 1 1 1 1128+64+32+16+8+4+2+1=256Remember* 0=off and 1=on -How would you find 193 in binaryoYou would get 193 and repeatedly divide it by 2oSecond you invert the order of remainders193/2=96+196/2=48+048/2=24+024/2=12+012/2=6+06/2=3+03/2=1+11/2=0+1 then invert remainders so,= 11000001Need a way to represent each object and