bcn-geodata

The official shapefiles from Barcelona, converted to GeoJSON and TopoJSON for making your life easier.

Recreate the files

• Go to the CartoBCN website and make an account. After that, click on Catàleg and select the SHP we are going to use, ED50. DIVISIONS ADMINISTRATIVES en format CAD/SHP/KMZ in this case.

• Extract the zip and the BCN_DIVADM_ED50_SHP.ZIP file again. We have five different files. First, the basic statistic area, then Àrea d'interès, which is an area important for statistic purposes (but it covers only Montjuïc), after that the neighbourhoods, the districts and the census area. We will first convert the shapefiles to GeoJSON, using the ogr2ogr tool. A good tutorial if you don't know what I'm talking about. Let's go!

A good catch beforehand by @oscarfonts: We use the official NTv2 grid of the ICC for improving the accuracy. Download the file and put it on the same folder as your shapefiles. Then run the following snippet:

ogr2ogr -f "GeoJSON" \
-s_srs "+init=epsg:23031 +nadgrids=./100800401.gsb +wktext" \
-t_srs EPSG:4326 \
output.json \
NAME_OF_YOUR_SHAPEFILE.shp

You can convert all the shapefiles that are interesting for you through this way.

• After that you will notice that the result is not particularly small, a problem if you want to use it on a web map. Now we are going to use TopoJSON, a format that can reduce the size up to a 85%! Install TopoJSON with npm (npm install -g topojson) and use this snippet:

topojson -o output.topo.json \
NAME_OF_YOUR.geojson \
-p barri=N_Barri,codi=C_Barri

In this case I'm using the BCN_Barri_ED50_SHP.shp file. Using the -p option I tell TopoJSON to preserve the name of the neighbourhood and its code, and rename them to barri and codi. You can adapt this to your needs looking at the GeoJSON properties for each file.

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Congrats! Now you have a set of TopoJSONs ready to visualize! Look at the TopoJSON command line reference for more powerful options.

Source: Ajuntament de Barcelona / CartoBCN. License: CC-BY.