Consider pros/cons of moving the Open Ownership map to higher resolution map images to make smaller islands visible

[StephenAbbott]

Smaller islands like Mauritius and other locations that Open Ownership works with are not visible on the Open Ownership Map as we are using a lower resolution GeoJSON file.

Need to consider the right balance here to see if it is more important to consider page speed or for users to be able to zoom in and click on these small islands.

[philgyford]

Using the current source of data, our current map data file is 577KB, the next one up is 3.9MB. There are some things we could do to reduce that:

• Remove fields from the data that we don't use
• Reduce the resolution a bit so it's better than what we have now but only as high as necessary
• Convert to TopoJSON from GeoJSON, which is a smaller format, which would also require a bit of a code change to handle it.

I say all this being far from an expert on this stuff, but have read things like https://blog.mastermaps.com/2012/11/how-to-minify-geojson-files.html (which I've just realised is 10 years old, so there may be newer better ideas around)

[StephenAbbott]

Thanks @philgyford. Am going to leave this issue here to come back to after launch. Will be good to do more investigation

[philgyford]

@StephenAbbott I can look into this again – just checking whether you've had any further thoughts on this since, or if there are any newer requirements I should bear in mind?

[StephenAbbott]

@philgyford There is a newer issue - #232 - which came up in reference to the current resolution of the map as there is interesting activity happening in jurisdictions which are not countries. But I fear our team doesn't have the resources to track all these jurisdictions as well as national level changes. I'm discussing this at present with my team but the issue is still closed for now.

There is also still currently the same issue as before where small island countries like Mauritius or Barbados are doing interesting work relating to beneficial ownership reforms but cannot be found/clicked through to from the map.

[philgyford]

I've done some work on the map now which means the smaller islands show up and the map file is much smaller.

• We use the "1:50m Cultural Vectors" "Admin 0 - Countries" map from https://www.naturalearthdata.com/downloads/50m-cultural-vectors/
• Using https://mapshaper.org we then simplify the outlines a bit and download it as TopoJSON (smaller than GeoJSON)
• There's a new script that processes that file, discards data we don't use, and fixes one other little issue
• The JavaScript now works with TopoJSON instead of GeoJSON.

So you can now zoom in click on Mauritius and Barbados (we could allow zooming in further if that helps?) and the size of the map file has been reduced from 577KB to 115KB.

[StephenAbbott]

Fantastic work, @philgyford! Changes sound great all round. I'll get this a test on staging 👏 👏 👏

[StephenAbbott]

Signed off ✅