JSON Maps of Philippine Administrative Boundaries
Philippine administrative boundaries in geojson and topojson format at various resolution.
The github repository contains Philippines vector maps suitable for use on web applications either as an overlay to interactive map services using Leaflet or rendered on natively using d3js.
Background
A few years ago, I was looking for low-resolution map files that I can use to render natural hazards map on the web. I found high- resolution shapefiles but I still have to do post-processing to optimize the maps to satisfy my requirements. Basically, high- resolution shapefiles are not really practical for rendering web maps because of their file size.
I needed vector maps that can render fast. Also, I wanted to partition the map data so I can incrementally load portions of the map asynchronously. So I wrote a few scripts to do the conversion and partitioning that I needed.
How it Works
Shapefiles to GeoJSON conversion with high fidelity was done using ogr2ogr.
The high fidelity GeoJSON file is "downsampled" using mapshaper with
-simplifyflag at 10% (hires), 1% (medres), 0.1% (lowres) settings.GeoJSON is then converted to a more compact topojson format using geo2topo.
The tools mentioned above can be used to do all sorts of post-processing on your shapefile. You can refer to the scripts to see how I did it. I would recommend having a look at these tools if you want to customize your own transformations.
Sample Maps
Files are generated for all locations in the Philippines at all administrative levels.
The maps are partitioned per area and administrative levels. For example, each region map will show provincial boundaries in that region.
Here is for Region II, Cagayan Valley Region:
provinces-region-cagayanvalleyregionii.topo.0.1.json
The same with municipalities and cities.
Here is for Metro Manila:
municities-province-47-metropolitanmanila.topo.0.1.json
Contributing
Contributions are always welcome, no matter how large or small. Github Project Link