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Finding Data for your GIS
Spatial data come from a variety of sources, perhaps including your own database files and spreadsheets. Most federal, state, regional and local governmental agencies make their GIS data available to the public. Some private companies also provide data for use in your GIS.
The guidelines below outline the basic search procedure for finding on-line spatial data.
Steps for Finding Spatial Data
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note: If you have absolutely no idea where to start or what question to ask, you are allow to skip GO and consult with the GIS staff before beginning your search
Review the spatial databases available in the SAL. The SAL is constantly acquiring and developing spatial datasets. Updates are discussed on on the SAL's blog.
Explore the connections collected for online spatial data sources. These connections are broadly categorized as follows:
- Learning Resources (resources for teaching & learning GIS)
- State & Regional Data Centers (primarily New England)
- National Data Sites
- Natural Science Data
- Social Science Data
- Cartographic Resources
- Reference Sites
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Crawl the Web with search engines like Google.
Syntax Examples:
historic "new england" gis
"population China .e00"
"bedrock Alaska .shp"
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Search GIS support mailing list archives available at the following web sites:
- ESRI Support Center
The SAL uses ESRI software (as do most colleges and universities) Users often post queries to these forums looking for GIS data. The summaries are often most useful.
My favorite listserves:
- EdGIS [Educational Applications of GIS]
- NITLE GIS [teaching & learning GIS at liberal arts]
- CONGIS [Biological Conservation and GIS]
- CTGIS-L [Connecticut GIS Users]
- NEARC [Northeast ArcInfo User Group]
- VGIS-L [Vermont GIS]
- STARServ [Spatial Technologies & Remote Sensing]
- CrimeMap [crime analysis & mapping]
A sample posting of mine that yield data:
"EDGIS listers,
I have been asked to find or perhaps develop an animated map showing the
settlement of the contiguous US (~ 1700's to present day). Any ideas of
an appropriate dataset available for constructing the animation? I know
about the Historical Census Browser at the University of Virginia and
can grab historical census data and back into an animation of sorts.
Any other thoughts?
Many thanks and I will sum. Jon"
The simple post yielded over a half dozen responses and ultimately led to a tidy little dataset that allowed us to produce an animation of US settlement.
Some tasty blogs:
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Post your own query to one of the above GIS lists. Be sure to have done the keyword search of the list archive first. |
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Consult the GIS Staff in the Spatial Analysis Lab. |
Tips and other thoughts:
- Are the spatial data in a GIS software format: e.g. Shapefile (.shp), Geodatabase (.mdb) or Arc/Info (.e00)?
- Is the spatial reference (coordinate system for the layer) defined? Does this match the spatial reference of your other data?
- What is the scale of the spatial data? Does it match your other data?
- At what summary level are the tabular data (county, block group, state, etc)?
- How recent are the data?
- What were the sources for the data?
- What are the copyright requirements?
- Is there metadata associated with the data?
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In
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