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Comment by arpineh | Hacker News Reader

I would love to see more details about this.

How did you implement your data path from getting GIS data (shapefiles I presume) to PostGIS then GeoJSON and finally into ThreeJS?

What about combining the statistical data with the location?

And the heatmap/choropleth, is that something Three.js can do?

I have no knowledge of developing 3D stuff, but I have been looking into using D3 with canvas rendering just for this kind of visualizations. I'm playing with multidimensional data as stacked 3D cubes. So, getting something like this would really bootstrap my project to another level. Any thoughts about open sourcing?

In all, this looks very useful and expendable. The sky is the limit. Literally, when is sky coming? ;)

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> The sky is the limit. Literally, when is sky coming? ;)

Definitely one of my favourite comments about the project so far! =p

The rough and ready approach we took to transforming data was to import the shapefiles into PostGIS using pgShapeLoader, doing any manipulation in PostGIS and exporting straight out to GeoJSON using the ST_ToGeoJSON method in PostGIS, or using the GeoJSON options in ogr2ogr. From there it's a simple case of importing the JSON into Three.js and constructing the objects from the vertex coordinates.

Re: Combining statistical data with the geographic data, we can do that with GeoJSON and you can use ogr2ogr to include related data about each location when exporting to GeoJSON.

The choropleth map is something we constructed from scratch. In reality, it's nothing more than a bunch of shapes in Three.js that each have a different material colour – it's very simple.

D3.js is a fantastic place to start. In fact, that's exactly where we started with all this. We actually use the Geo module within D3 for a few parts of ViziCities.

We haven't decided yet about opening the full project but we'll certainly be documenting and releasing aspects of it (most of the juicy bits). We'll announce that via the @ViziCities Twitter account.

As for the sky… it's coming ;)

Ah, thank you for your reply.

There was a WebGL 3D flying simulator on HN few weeks back which used the sky and light changes to great effect. Perhaps something like morning rush hour traffic against evening or rainy days againts sunny.

I'll definetely have to delve more into PostGIS. Three.js should follow when I get a better graps of D3. I think there was an example on how to generate a satellite 3D like map from GeoJSON at Mike Bostocks example site.

Very exciting stuff!

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