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GIS Center: Where to Find Data

Information and Resources Offered by the GIS Center at UC Merced.

Data Types

Spatial data contain geographic coordinates, such as longitudes and latitudes, allowing features to be drawn on a map.  Vector and raster data are examples of spatial data.

      Vector data are geometric shapes - points, lines, and polygons - drawn from stored coordinates.  Shapefiles are vector data.

      Raster data are grids of valued cells which display like pixels on a screen.  Satellite imagery are rasters.

Attribute Data are the information you want to communicate in your map, such as median household income or average annual rainfall, and are in tabular format.  Note:  If the data you want to map is not already available as a GIS layer, you can always create a CSV file of the data and join it to a boundary file

Large Data Repositories:

     ArcGIS Living Atlas - Curated data from Esri accessible directly from ArcGIS Online or Pro

               Learn how to add American Community Survey data directly to your map from Living Atlas.

      ArcGIS Hub -- Esri's open data hub with > 250,000 data sets from > 5000 organizations

     Natural Earth - worldwide vector and raster data including administrative boundaries and physical features.

      Geospatial Data Gateway (Natural Resources Conservation Service) - Demographic and physical data (raster & vector) by US county.

      UC Berkeley Library Geodata -- Easy to search, vector and raster data's top ten picks for GIS data online, and 15 sites for satellite imagery.

Vector Data

GADM -- worldwide administrative boundaries (more detailed than Natural Earth, larger files)

Openstreetmap - online map, crowed-sourced... exported data can be used in QGIS, but not ArcGIS

Bureau of Land Management -- public lands data

California State Geoportal - maps, apps, and data from over 30 state departments

United Nations Environmental Programme -- spatial and non-spatial data on a variety of themes

Raster Data

USGS Earth Explorer and 3DEP - Satellite and aerial imagery and Digital Elevation Maps at 1, 1/3, and 1/9 arc-second resolution  User's Guide

Copernicus - Raster data for Europe, including DEMs, land use, and satellite imagery

The David Rumsey Historical Map Collection - Not all maps are georeferenced, but you can do it yourself with their Georeferencer app!

The Harvard Map Collection - Over 2700 scanned historical maps.

OpenTopography - Direct access to USGS 3D Elevation Program and NOAA datasets as well as derived data products and visualizations (DEMs, slope, hillshade, contours, etc.).  Very user friendly.

Attribute Data (Tabular) -- US population statistics

        Learn how to add American Community Survey data directly to your map from Living Atlas.

IPUMS - world census & survey data integrated across time & space

California State Geoportal - maps, apps, and data from over 30 state departments