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Geospatial Data: Using Data

This guide describes how to find and use the DREAM Lab's spatial data, as well as data that is available freely online.

Aerial Imagery: Georeferencing and Orthorectifying

Georeferencing converts a digital image into raster data usable in a GIS.  The term is often used interchangeably with Orthorectification, which is a more involved process.

ESRI's ArcGIS (available to all UCSB affiliates), and QuantumGIS (free-and-open-source) all contain the tools necessary to apply control points and transformations to your digital image files so that they can be used in GIS.  We are happy to get you started with this process.  Tufts University has an excellent tutorial on georeferencing scanned maps.


If you have address-based data that you wish to map in GIS, you'll need to assign latitude and longitude coordinates to your data so you can plot them as points. This process is known as geocoding. Geocoding in ArcGIS Desktop is a lengthy process, so you may consider using one of the following free online geocoding services:

Google Geocoding API
Provides a direct way to access a geocoder via an HTTP request, and is the basis for most online geocoding services. The service also allows you perform "reverse geocoding," which turns coordinates into addresses. Use of the Google Geocoding API is subject to a query limit of 2,500 geolocation requests per day.

USC Geocoding Service
The USC's GIS Research Laboratory provides a number of geocoding services for translating addresses, including a batch geocoder that allows up to 2,500 address-to-point conversions. You can also trace and store polygons and calculate shortest paths here.

Batchgeocode - Map Multiple Locations by Address
A free online tool to do basic geocoding. Once your information is geocoded, you can then use it for analysis or visualization in a GIS. The site also has a tool to calculate distances to multiple addresses from a single point.

Getting Help

Getting Started with GIS - a free online course provided by ESRI.