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Wednesday, 2 February 2011

Natural Earth vectors in the cloud!

Natural Earth is a jewel among public domain datasets. I’ve made the entire vector dataset (175,000 features!) available on Google Fusion Tables (GFT). Now you can easily query and download vector geometries in different formats (KML, GeoJSON, WKT and SVG) with associated attributes. This experiment will show if Google Fusion Tables can be used as a cloud-based feature server.

All 139 Natural Earth fusion tables are listed in this table. Every table is public and exportable. A few features are missing at 1:10 million scale because the polygons where too large for GFT (the character limit for a given cell is 1 million characters). The data features are described on the Natural Earth website. Table names are identical to the original shapefile names. 

All tables include 4 geometry columns containing vector data in various formats:
The geometries are in EPSG:4326 (longitude/latitude, WGS84). I've only included three decimals to save space and bandwidth. The longitude accuracy is approximately 111 m at equator, which should be sufficient for this dataset.  

Unfortunately, the built-in mapping features of GFT are useless for world maps containing polygons and lines (both line and polygon geometries are displayed as markers at zoom levels less than 5).

Update from Google: "I'm delighted to announce an update - Due to some impressive engineering wizardry on our team, the defaults for zoomed-out views are much improved. Tables with less than 1000 features mapped will show lines and polygons for three additional zoom levels. In addition, many of Bjørn's remaining tables have been granted individual exceptions for visualizing within Fusion Tables; any re-use through merging will inherit this exception. Happy mapping!" 

You can download the data using the Google Fusion Tables API, and render the vectors in your own web mapping application. 

Examples of how to use Natural Earth in the cloud will follow in later blog posts. Stay tuned!