Data Sources
Pre-requisites: Intro to Spatial Data, Metadata, Consumable Services
Objectves:
- Understanding how to assess data sources
- Recognize credible data sources
Data Collection
Credible Data Sources
Not all spatial data is created equal, but there is a host of quality spatial data out there if you know where to look. Some elements to look at when evaluating the quality of a data product are:
- Normalization - Do similar datasets have similar formats?
- Accessibility - How can you access the data?
- Accountability - Is the organization considered an authority of this type of data?
Here are a few data sources to check if you are looking for some spatial data:
Global Administrative Areas (GADM)
“GADM is a spatial database of the location of the world’s administrative areas (or administrative boundaries) for use in GIS and similar software. Administrative areas in this database are countries and lower level subdivisions such as provinces,departmens bibhag, bundeslander,etc… GADM describes where these administrative areas are and for each area it provides some attributes, such as the name and variant names1.”
United States Geological Survey (USGS)
The USGS has had a long history in mapping, and has provided quality topographic data since maps were hand-drawn. The USGS can provided detailed data delimited by Quadrangle or larger extents through FTP or their EarthExplorer portal. Some notable products include:
National Aeronautics and Space Administration (NASA)
NASA is the go-to for remotely sensed data due to their history as a leader in satellite data and continued growth in data products offerings. Some useful data products are:
- Modern-era Retrospective Analysis for Research and Applications (MERRA)
- Moderate Resolution Imaging Spectoradiometer (MODIS)
- Landsat-8
- Global Change Master Directory
National Oceanic and Atmospheric Administration (NOAA)
NOAA provides a variety of data products for weather and climate. NOAA has an extensive Thredds catalog of climate data available at http://www.esrl.noaa.gov/psd/thredds/calatlog/Datasets/catalog.html using the OPeNDAP protocol.
U.S Census Bureau
The U.S. Census is the authority on national demographic data and creates standardized datasets for the nation on both census tract and block level.
-
- Topologically Integrated Geographic Encoding and Referencing (TIGER) Products
- TIGER products are spatial extracts from the Census Bureau’s MAF/TIGER database containing features such as roads, railroads, rivers, as well as legal and statistical geographic areas. The Census Bureau offers (these products) in several file types2.”
Local and regional governments
Most states maintain repositories of spatial data characteristic or pertinent to their scope. Some organizations to look for would be state geologic surveys, natural resource departments, city and county governments.