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Finding and Using GIS Data

The AGS Library's Guide to Finding GIS data and working with it for your specific project needs


Welcome Cartography Students!

This guide was updated for the Spring 2024 class of Geog 405/705: Cartography.

Below you will find some important links and reminders to topics I covered in my guest lecture on February 14th, 2024.

Links used in class

Best Bet Geoportals

Best Bet Geoportals

Wisconsin and Local Data

Other Geoportals


Aerial Photography

Aerial Photography

There are a couple of options for accessing aerial photography, and it really depends on what you need to do with it. There are three options below:

1. Use a county map viewer.

If you only want to look at aerial photography or if you want to compare multiple years over a large area, your best bet might be to use the aerial photo layers available to you on existing map viewers. Most County governments have a web map viewer on their website that lets you view aerial photography along with other important layers. Most of these sites will let you export an image clip or a PDF map. This is a great option of you are just exploring what's out there before diving in to your analysis.

2. Download/Request the files

Aerial photography can take up a lot of space on your hard drive, but depending on your needs it might be the best option. If you plan to do analysis on the layers (such as analyzing land use), the tools you use may require specific formats or be more repeatable if you store the files on your computer or in cloud storage. If you need TIFF, ArcGRID, JPEG, or other formats, make a request from the AGSL or download files from a geoportal.

3. Use a Web Mapping Service

If you would like to use Aerial Photography in GIS but don't want to download and save files on your machine, web mapping services are a great option. The Milwaukee County Land Information Office makes all aerial photography back to 1963 available to use as a service. A web connection is required, but most users find that it's a much more efficient option, especially over large areas.  A few other counties share their aerial photos as a web service, too!