GIS Tutorial 1 Lecture 5 Importing spatial and attribute data

Outline  Map projections  Coordinate systems  GIS data sources  Vector data formats  Raster data formats 2 GIS TUTORIAL 1 - Basic Workbook

MAP PROJECTIONS Lecture 5 3 GIS TUTORIAL 1 - Basic Workbook

Latitude and longitude  Longitude (meridians) 4 GIS TUTORIAL 1 - Basic Workbook

Latitude and longitude  Latitude (parallels) 5 GIS TUTORIAL 1 - Basic Workbook

Longitude and latitude ° Longitude (prime meridian) 0 ° Latitude (equator) 0 6 GIS TUTORIAL 1 - Basic Workbook

Longitude and latitude Pittsburgh, PA USA  Coordinates 7 GIS TUTORIAL 1 - Basic Workbook

Long/Lat coordinates  Degrees, minutes, and seconds (DMS):  40° 26′ 2″ N latitude  -80° 0′ 58″ W longitude  Decimal degrees (DD)  1 degree = 60 minutes,  1 minute = 60 seconds  40° 26′ 2″ =  /60 + 2/3600 =  =  ° 8 GIS TUTORIAL 1 - Basic Workbook

Long/lat coordinates Translated to distance  World circumference through the poles is 24, miles, so for latitude:  1° = 24, / 360 = 69.1 miles  1′ = 24, / (360 * 60) = 1.15 miles  1″ = 24, * 5,280 / (360 * 3,600) = 101 feet  Length of the equator is 24, miles 9 GIS TUTORIAL 1 - Basic Workbook

Mercator projection (1569)  Conformal projection  Cylindrical  Parallels and meridians at right angles  Linear scale is constant in all directions around any point  Preserves angles and shapes of small objects  Distorts the size and shape of large objects  Map projection for nautical purposes 10 GIS TUTORIAL 1 - Basic Workbook

Hammer – Aitoff ( )  Equal-area  Modified azimuthal projection  Good for population density (world area)  Difficult to see some areas 11 GIS TUTORIAL 1 - Basic Workbook

Robinson projection (1961)  Pseudocylindrical  Neither equal area nor conformal  Meridians curve gently, avoiding extremes  Good compromise projection for viewing entire world  Used by Rand McNally since the 1960s and by the National Geographic Society (1988 and 1998) 12 GIS TUTORIAL 1 - Basic Workbook

Albers Equal Area  Conic projection  Scale and shape are not preserved, distortion is minimal between the standard parallels  Standard projection for British Columbia, U.S. Geological Survey, U.S. Census Bureau 13 GIS TUTORIAL 1 - Basic Workbook

Projection important  Measurements used to make important decisions  Comparing shapes, areas, distances, or directions of map features  Feature and image themes are aligned Los Angeles New York Los Angeles New York Projection: Mercator Distance: 3, miles Projection: Albers equal area Distance: 2, miles Actual distance: 2,451 miles 14 GIS TUTORIAL 1 - Basic Workbook

Projection not important  Business applications  Not of critical importance  Concerned with the relative location of different features  On large scale maps — street maps  Distortion may be negligible  Map covers only a small part of the earth’s surface 15 GIS TUTORIAL 1 - Basic Workbook

COORDINATE SYSTEMS Lecture 5 16 GIS TUTORIAL 1 - Basic Workbook

Geographic Coordinate System (GCS)  Spherical coordinates  Angles of rotation of a radius anchored at earth’s center  Latitude and longitude  Census Bureau TIGER files 17 GIS TUTORIAL 1 - Basic Workbook

U.S. Census GCS example 18 GIS TUTORIAL 1 - Basic Workbook

Rectangular coordinate system  Used for locating an intersection on a flat sheet of graph paper or a flat map  Cartesian coordinates (x,y)  State plane and UTM 19 GIS TUTORIAL 1 - Basic Workbook

State Plane coordinates  Established by the U.S. Coast and Geodetic Survey in 1930s  Originally North American Datum (NAD 1927)  More recently NAD 1983 and 1983 HARN  Used by local U.S. governments  All positive coordinates in feet (or meters) 20 GIS TUTORIAL 1 - Basic Workbook

State Plane zones  125 zones  At least one for each state  Cannot have zones joined to make larger regions  Follow state and county boundaries  Each has its own projection:  Lambert conformal projection for zones with east-west extent  Transverse Mercator projection for zones with north-south extent 21 GIS TUTORIAL 1 - Basic Workbook

State Plane zones 22 GIS TUTORIAL 1 - Basic Workbook

State Plane zones 23 GIS TUTORIAL 1 - Basic Workbook

Pittsburgh neighborhoods as state plane coordinates 24 GIS TUTORIAL 1 - Basic Workbook

Universal Transverse Mercator (UTM)  Rectangular coordinate system  Used by U.S. military  Covers entire world  Metric coordinates  Longitude zones are 6° wide  Latitude zones are 8° high 25 GIS TUTORIAL 1 - Basic Workbook

Coordinate system summary  Geographic coordinate system  U.S. Census  State plane coordinate system  Local governments  U.S. military  Projections defined in ArcCatalog or ArcMap (.prj) files  First file added in a map document sets the projection (others will adjust to it as long as they have a.prj file) 26 GIS TUTORIAL 1 - Basic Workbook

GIS DATA SOURCES Lecture 5 27 GIS TUTORIAL 1 - Basic Workbook

GIS data sources  ESRI  U.S. Census  USGS and other government sources  GDT Dynamap/2000 U.S. Street Data  Engineering companies  land surveys, aerial photos, CAD drawings  University Web sites (e.g. Penn State’s PASDA)  Others? 28 GIS TUTORIAL 1 - Basic Workbook

GIS data sources  30+ million Internet search results  type “GIS data download” or “population China.e00  add the name of the state, county, or city to the search 29 GIS TUTORIAL 1 - Basic Workbook

GIS departments Web sites  Washington, D.C.  dcgis.dc.gov/  Chicago, IL   Austin, TX  Tip: Search by county name (Travis County, Texas)   ftp://ftp.ci.austin.tx.us/GIS-Data/Regional/coa_gis.html 30 GIS TUTORIAL 1 - Basic Workbook

ESRI’s Web site  hic-data.html hic-data.html 31 GIS TUTORIAL 1 - Basic Workbook

U.S. Census Bureau  Started building a map infrastructure in the late 1970s and early 1980s  Census mapping needs were twofold:  To assign census employees to areas of responsibility, covering the entire country and its possessions  To report and display census tabulations by area, officials determined that the smallest area needed for these purposes is a city block or its equivalent 32 GIS TUTORIAL 1 - Basic Workbook

U.S. Census Bureau  Compiles all line features used to create a block layer for the entire country  Map features smaller than are the responsibility of local governments  deeded land parcels  buildings  street curbs  parking lots  others? 33 GIS TUTORIAL 1 - Basic Workbook

Census TIGER/Line files  Topologically Integrated Geographic Encoding and Referencing files  Census Bureau’s product for digital mapping of the U.S.  Available for the entire U.S. and its possessions  Include the following geographic features  roads and street centerlines  railroads  rivers  lakes  census statistical boundaries 34 GIS TUTORIAL 1 - Basic Workbook

TIGER census tracts  Statistical boundary (below county level)  between 1,000 and 8,000 people (in general)  1,700 housing units or 4,000 people  homogeneous population characteristics (economic status and living conditions)  normally follow visible features  may follow governmental unit boundaries and other nonvisible features  more than 60,000 census tracts in Census GIS TUTORIAL 1 - Basic Workbook

PA tracts 36 GIS TUTORIAL 1 - Basic Workbook

Allegheny County tracts 37 GIS TUTORIAL 1 - Basic Workbook

City Pittsburgh tracts 38 GIS TUTORIAL 1 - Basic Workbook

TIGER census block groups  Subdivision of a census tract  400 housing units, with a minimum of 250 and a maximum of 550 housing units  Follow clearly visible features such as roads, rivers, and railroads 39 GIS TUTORIAL 1 - Basic Workbook

Census block groups 40 GIS TUTORIAL 1 - Basic Workbook

TIGER census blocks  Smallest geographic area for which the Census Bureau collects and tabulates decennial census information  Visible boundaries  street  road  stream  Shoreline  Nonvisible boundaries  county, city, neighborhood boundary  property line 41 GIS TUTORIAL 1 - Basic Workbook

Census blocks 42 GIS TUTORIAL 1 - Basic Workbook

Other TIGER layers 43 GIS TUTORIAL 1 - Basic Workbook

U.S. Census Bureau data tables  GIS TUTORIAL 1 - Basic Workbook

45 GIS TUTORIAL 1 - Basic Workbook Geospatial Website for U.S.: geodata.gov

Summary File (SF1) tables 46 GIS TUTORIAL 1 - Basic Workbook

Summary File (SF3) tables 47 GIS TUTORIAL 1 - Basic Workbook

SF tables comparisons SF1  Population  Age  Sex  Race  Housing units  FFH SF3  Income  Educational attainment  Citizenship  Transportation  Detailed housing 48 GIS TUTORIAL 1 - Basic Workbook

Census summary  Shapefiles downloaded from or  Data tables downloaded from American Factfinder  Data joins needed to join SF1 or SF3 to shapefiles GIS TUTORIAL 1 - Basic Workbook 49

VECTOR DATA FORMATS Lecture 5 50 GIS TUTORIAL 1 - Basic Workbook

ArcInfo coverages  Created using ESRI’s ArcInfo software  Older format  Set of files within a folder or directory called a workspace  Files represent different types of topology or feature types 51 GIS TUTORIAL 1 - Basic Workbook

Coverage attribute table  Area and perimeter  Coverage_ and Coverage_ID 52 GIS TUTORIAL 1 - Basic Workbook

53 GIS TUTORIAL 1 - Basic Workbook ArcInfo Export files.e00 export interchange file ArcToolbox translates into ArcGIS Creates a coverage

Shapefiles  ArcView native format  Minimum files  shp–stores feature geometry .shx–stores index of features .dbf–stores attribute data  Additional files .prj–projection data .xml–metadata .sbn and.sbx–store additional indices 54 GIS TUTORIAL 1 - Basic Workbook

CAD drawings  CAD software  Autodesk, AutoCAD (.dwg)  Bentley, Microstation (.dgn,.dxf)  Often used by engineering companies  Better digitizing precision 55 GIS TUTORIAL 1 - Basic Workbook

CAD drawings 56 GIS TUTORIAL 1 - Basic Workbook

CAD layers 57 GIS TUTORIAL 1 - Basic Workbook

Event files Data table that includes map coordinates, such as latitude and longitude or projected coordinates 58 GIS TUTORIAL 1 - Basic Workbook

Event files 59 GIS TUTORIAL 1 - Basic Workbook

Export event files 60 GIS TUTORIAL 1 - Basic Workbook  Creates point features

RASTER DATA FORMATS Lecture 5 61 GIS TUTORIAL 1 - Basic Workbook

Digital file formats  TIFF (Tagged Image File Format) .tif file extension  Very high quality images  Commonly used in publishing  Sizes are large because it is uncompressed  GIF (Graphic Interchange Format): .gif as its file extension.  Ideal for schematic drawings that have relatively large areas with solid color fill and few color variations.  Small file sizes 62 GIS TUTORIAL 1 - Basic Workbook

Digital file formats  JPEG (Joint Photographic Experts Group): .jpg file extension.  Most widely used format for photographs and other images that have a lot of color variations  Uses file compression at the expense of picture detail, if you specify a lot of compression 63 GIS TUTORIAL 1 - Basic Workbook

Summary  Map projections  Coordinate systems  GIS data sources  Vector data formats  Raster data formats 64 GIS TUTORIAL 1 - Basic Workbook