When I first looked at Even’s work, there was no support for reading the spatial indexing files of a FGDB. Of course, without spatial indexing, large data sets would perform quite poorly. Its worth noting that Even’s project now supports spatial indexing, but GDAL 1.1 uses the older version. The current latest TileMill dev build to include an installer – TileMill-v0.10.1-291 – should similarly lack spatial indexing.
To make my test exciting, then, I decided to use a large dataset. I fired up Ogr2Org and created an FGDB dump of the full Open Street Map globe (OSM2PGSQL schema). I tested the data in ArcMap and OGR and everything was quite zippy. Upon attempting to load the FGDB in TileMill, it crashed. I can’t say I didn’t expect this.
It’s worth noting that ESRI’s File Geodatabase API is free as in beer. I think Even’s work is fantastic for the community, but I’m not sure why MapBox didn’t use that other GDAL FGDB driver. Nevertheless, OSS marches on, and I expect we’ll see these recent features bubble their way up. I look forward to seeing FGDB spatial-indexing support hit TileMill, as I believe the idea has real legs.