Public Lab is an open community which collaboratively develops accessible, open source, Do-It-Yourself technologies for investigating local environmental health and justice issues.
*Part of the [Grassroots Mapping Curriculum](/wiki/mapping-curriculum) series.*
MapKnitter is a free and open source tool for combining aerial images into a map, or composite image. Informally, we call this "stitching a map" and it's useful if you have many images of overlapping or identical areas, and getting either a web map or a printable map from your photos.
<iframe width="640" height="480" src="https://www.youtube.com/embed/0h6MBH6f2js?rel=0&showinfo=0" frameborder="0" allowfullscreen></iframe>
MapKnitter can make maps from any image source, but it was designed for making maps with aerial photos from balloons and kites.
Start using [MapKnitter.org](http://MapKnitter.org) or read on for more documentation!
Once you're map is complete, you can download it as a single image in JPG and other formats. Read about the new Cloud exporter here:
Learn more about [exporting maps in MapKnitter here](/mapknitter-exporting).
* [Decisions with distortions](https://www.youtube.com/watch?feature=player_embedded&v=S8uUM3p3_Bk#!) - Learn about the design process of stitching maps when images are highly distorted or include tall buildings. This tutorial is in Photoshop, but the techniques are applicable to MapKnitter as well.
* [Infrared multispectral compositing](/wiki/mapknitter-multispectral) (no video, in progress) Learn how to combine an infrared dataset with your map to assess photosynthesis. (Also: learn [how to collect infrared imagery](/tool/near-infrared-camera))