Library Guides: GIS for Public Health: A Guide: Geospatial Data

Databases

GeoRef This link opens in a new window
Produced by the American Geological Institute, this database is a comprehensive geoscience database containing over 2.2 million bibliographic records from more than 3,000 journals and other sources. GeoRef provides coverage in subject areas such as mineralogy and crystallography, general mineralogy, mineralogy of silicates, and mineralogy of non-silicates.
PolicyMap This link opens in a new window
A data and mapping tool that enables government, commercial, non-profit and academic institutions to access data about communities and markets across the US.
Social Explorer This link opens in a new window
Social Explorer “contains over 18,000 maps, hundreds of profile reports, 40 billion data elements, 335,000 variables and 220 years of data”. It can be used to locate census tract boundary information from 1940 to the present.

Raster Data

A raster consists of pixels organized into a grid. Each cell is comprised of a value representing information. Raster data is data in a .JPG, .TIF, .GIF or similar format. Items scanned using a flatbed scanner like this map are examples of raster files.

The map below is an example of raster data. Scanned maps must then be geo-referenced with accurate location data to align them with a map coordinate system.