Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
July 23-27, 2012 What Is Geographic Data and Where Can I Find It? Miriam Schmidts Geri Miller
Agenda • What is Geographic Data? • Where can I find it? • Online sources • Converting existing data • Creating it yourself
Geographic data Is this geographic data? yes yes yes
Geographic data • Information describing the location and attributes of things, including their shapes and representation. • Geographic data is the composite of spatial data and attribute data.
GIS data models Real world Vector Raster
Raster data - a cell based view Imagery Elevation Vegetation
How GIS data stores location • Pairs of X,Y coordinates • Longitude and Latitude • Projected X,Y coordinates Y X<0 Y>0 X>0 Y>0 (0,0) X X<0 Y<0 X>0 Y<0
How GIS data is stored Vector formats • Geodatabase feature classes • Shapefiles • Name.shp • Name.shx • Name.dbf • Coverages / E00 • KML/KMZ Raster / Image formats • Tiff • MrSID • Many more….
Layer and map packages • Map package • Full contents of map document • Map properties • Data frames • All layers and data • Layer package • Full contents of a single layer • Includes layer's data • May also apply to group layer
Summary: Accessing GIS data online • ArcGIS.Online: http://www.arcgis.com/home/ • Ready to use data and basemaps • Data and Maps for ArcGIS • Esri Data page: http://www.esri.com/data/find-data.html • Imagery, Streets, Shaded Relief, Topographic Data • Demographics, Consumer Spending, Business, and Marketplace Data • Free Data • 2010 Census TIGER/Line® Shapefiles
Data Documentation When was it made? • Item Description • Title, Thumbnail, Tags • Summary (Purpose) • Description (Abstract) • Credits • Use Limitations • Extent • Scale range • Metadata • More elements • Complies with standards How was it made? Can I use it? Who made it? What's this? What's this?
Summary: More online data sources Government agencies, for example: • http://www.data.gov/ • http://data.geocomm.com • http://cumulus.cr.usgs.gov/ • http://gis.fema.gov/DataFeeds.html • Colleges and Universities, for example: • http://gis.harvard.edu • States, counties, cities • Commercial vendors • Many….
Converting existing data • Converting spatial data formats • Shapefile Geodatabase • E00 Coverage Geodatabase • Any Any • Converting tabular data into spatial data
Converting tabular data Display X,Y Data Geocoding
Summary: Converting tabular data • Display X,Y data: converting X,Y coordinates into points • Need separate columns for the X and the Y coordinate • Can be longitude and latitude or projected coordinates • Need to define the coordinate system that the x,y • Geocoding: converting address information into points • Can geocode single addresses or a table of addresses • Use online geocoding service or build your own address locator
Creating geographic data • Vector • Digitized from paper maps or from imagery • Survey data, GPS, ranging • Converted from imagery or scanned maps • As output from geoprocessing • Raster • Aerial cameras/scanners • Classification from imagery • As output from geoprocessing
Summary: Digitizing vector data If necessary, create a shapefile or geodatabase feature class If necessary, add it to the map Start an edit session Choose feature template & construction tool Create new feature Add or edit attributes Save edits
Steps to evaluate UC sessions • My UC Homepage > “Evaluate Sessions” • Choose session from planner OR • Search for session www.esri.com/ucsurveysessions
Thank you for attending • Have fun at UC2012 • Open for Questions • Please fill out the evaluation: • www.esri.com/ucsessionsurveys • First Offering ID: 623 • Second Offering ID: 1949