Choose a tab above.
  • MapTube maps from
  • SurveyMapper maps from
  • OpenStreetMap map data from a copy of the OpenStreetMap database
  • Click on a map to add your own markers with captions
  • Access your data from the Gemma iPhone app's data collector
  • Paste in your own location data and measurements
You can click to add points to your map, and display labels with the points, directly on the map.

Click to add markers to the preview map:

Note: Captions and icons will appear once the layer is added to the main map.
You can add data here that you have saved using the GEMMA Data Collector iPhone app. Advanced users can also manually add tabular latitude/longitude/metric data here.

Mobile Data Collector

Have your own data?

You'll be given a shortlink to use. Privacy note: All maps you create are publically accessible.

Please wait, saving now...

Welcome to gemma. GEMMA the gerbil

What Can I Do?

Gemma allows you to build up maps with layers from many sources - MapTube, SurveyMapper, OpenStreetMap and manually collected data points.

Creating Maps

To create a map, just move the grayscale map to your area of interest, then click "Add new layer" and start adding the information you want.

Keeping Maps

You can save your maps so you can view them again later - you'll be given a shortcode to remember, and if you are logged in to Gemma, your map will be saved to the My Maps section. Also, you can create a PDF of your map easily, for printing out.

iPhone App

The Gemma iPhone app is a data collector - use it to record observations, and then upload them to the Gemma website for your maps!
Your map short-link is:

Copy this link now to share your map,
or to return to it in the future.

This will produce and download a PDF on an A4 sheet. The extent of the map on the PDF may be slightly larger than what you see in your browser.

Note that SurveyMapper layers are not available at this time for PDFs.

Keep track of your maps and collections by logging into Gemma using your Twitter Account