Optimize shapefiles. about click_that_hood

[mwichary]

Hints:

Load up in QGIS (via “Layer | Add Vector Layer…”), go to “Vector | Geometry Tools | Simplify geometries”, and then pick 0.0001 or 0.001 or whatever results in good optimization. Remember to check “Save to a new file” and point to a new shapefile. Remember that for names in UTF-8 it tends to mess things up, so double-check.

Also, saving GeoJSON from CartoDB results in a smaller file than saving GeoJSON from QGIS.

Some of the current files are too large, for example Mexico at 5.8M, San Diego at 5.2M, Lombardy at 4.5M. This is not only longer load times, but also slower drawing.

Perhaps a rule of the thumb should be for the size to never exceed 3M, or 1M, or for the size to never exceed NumberOfHoods * X.

[mlevans]

Matt Bloch's mapshaper - http://www.mapshaper.org + https://github.com/mbloch/mapshaper - would also be a good tool for this. It gives you a simple web or command-line interface for simplifying geometries.

[mwichary]

Thanks, Michael!

[mwichary]

I just used MapShaper to optimize US in 1810. It wasn’t smooth sailing (I needed to choose the middle mode, repair intersections, then export to shapefile, then convert to GeojSON in QGIS, then re-save in CartoDB), but it worked. :·)