Fully functional online GIS tool that easily lets users drop in existing data or draw right onto the map. This application is particularly useful in that it also allows common geoprocessing tasks to run right in the browser, with no need to install GIS software.

No sign-up is required.

Mapbox allows users to quickly build and share online web applications. Load CSV, KML or JSON files right into the browser and customize styles.

New users must create an account, and free accounts ("starter" accounts) are limited to 100MB of data storage and 50,000 map views a month. However, faculty and students can also request Mapbox Education accounts, which allow additional free storage capacity.

ArcGIS offers free online mapping services and allows users to share their maps with others. Save information as a CSV file and drag it right into the web application to visualize datasets. Visitors also can utilize a limited number of processing tools to evaluate mapped data.

New users must sign up for a free account in order to share or save maps.

Like Mapbox, CartoDB is one of the more popular online mapping applications with a simple interface. Users can upload databases and map layers and visualize them right in the map. Like true GIS web applications, the maps are dynamic and change as the underlying datasets linked to them change.

New users must sign up for an account. Free accounts are limited to a maximum of 50MB of data, and the user cannot remove the CartoDB logo or keep data private once uploaded.