GrassrootsMapping
Cartagen Knitter
More documentation is coming soon, but for now, check out the Knitter at:
Some places don’t have any existing map data! What do you do? Read on.
Tips
“I can’t see anything on Cartagen Knitter! What do I do?”
For areas with very little map data, it’s hard to see anything to use as a guide to stretch your images to. (see illustration)
To help, click the button with the following symbol, marked ‘Choose a background layer for reference’:
Then choose a source of satellite imagery to use as a background. For outside the US, we’re looking for viable sources of imagery to knit onto, and listing them here 
Exporting
JOSM
Some users may need to have and want to export a TMS so that they can trace it in JOSM or another cartography application. JOSM’s Slippy Map plugin (available in the plugins menu of JOSM) requires a non-standard TMS source, so the usual TMS link which Cartagen generates won’t work.
However, Cartagen generates an alternative at http://cartagen.org/tms/your-map/alt
To add this to JOSM, go to Advanced Preferences, and use the Add button to enter these key/value pairs:
key: slippymap.custom_tile_source_1.name value: Your map's name key: slippymap.custom_tile_source_1.url value: http://cartagen.org/tms/your-map/alt
Viewing a Cartagen Knitter export in JOSM.
Then go to the Slippy Map section of the Preferences panel and choose your map’s name from the dropdown menu. You may have to right-click the Slippy map layer from the main Layers panel on the main outdoor fountains screen, and enable it, and also try restarting the whole program. You can now use JOSM normally.
If you have to do this all locally (don’t have internet access) you could potentially use this script to convert the OSGeo compliant TMS Cartagen produces into one compatible with JOSM:
#!/bin/bash
for I in `find . -maxdepth 3 -mindepth 2 -name *.png`
do OLDNAME=`basename $I .png`
DIRNAME=`dirname $I`
RELATIVEPATH=${I#./}
ZOOM=${RELATIVEPATH%%/*}
NEWNAME=$((2**$ZOOM-$OLDNAME-1))
mv "$I" "$DIRNAME"/"$NEWNAME.png"
done
echo "$SEP2"
Bugs
For bug reports, please leave a note here, or email warren@mit.edu, or better yet, create an Issue at the Cartagen Github site http://github.com/jywarren/cartagen/issues
Development
- See Knitter Development for notes on in-progress and future work, or to get involved.