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Library Research Guides

Geospatial Data

Subject guide to finding and using geospatial data. Includes tutorials for using elevation data to make contours, and using aerial imagery layers to output imagery even more efficiently than Google Earth Pro can.

What is georeferencing?

Georeferencing is assigning real world locations to a raster.

Here, we are referring to georeferencing scanned maps and assigning coordinates to different parts of the image. This allows you to overlay the map with other maps and data in a system that understands coordinates, such as a GIS or a web map.

Different raster formats can be used as inputs for different tools. Common choices are TIFFs and JPGs. If your image is a PDF, you may want to convert it first in Photoshop or another program from PDF to a TIFF or JPG.

 

Things to consider when choosing a method for georefrencing:

  • What output format do I want? GeoTIFF? WMS? Tiles?
  • Is this a map I want to share online or keep offline in a desktop environment?

Options for Georeferencing

Mapwarper - online, serves up tiles

ArcMap

QGIS - open source, desktop GIS

ArcGIS Pro