![]() ![]() But that’s way ahead of me and this post. Ideally something similar would be possible using OpenLayers and the icosahedral geometry of the Dymaxion projection. I’d be remiss if I didn’t mention Mike Migurski’s remarkable work on the “Faumaxion” projection, which resulted in an experimental and path-breaking interactive browser that re-orients and re-configures its equilateral triangular coordinate system based on the map center and scale. But for custom projections like Dymaxion, OpenLayers includes the method, which I’m using like so: ![]() Proj4js contains most of your old favorites, like Lambert and Albers and Transverse Mercator. And this is almost always going to involve the Proj4js library, a port of PROJ.4.ījørn Sandvik provides a great introduction to projecting KML data with OpenLayers and Proj4js. But if you’re using all vector data - from KML, GeoJSON, or many other formats - you can take advantage of OpenLayers’ projection abilities. Of course, if you’re loading in Google or Bing tiles, you’ll have to stick to Web Mercator for any overlays in this case OpenLayers will just be transforming your overlay data from lat/long to Mercator for display. OpenLayers is unique in allowing coordinate system transforms from any arbitrary projection to any other. This is basically because of a decision Google made six or seven years ago and because web mapping platforms have been used more for reference than thematic mapping. ![]() Most web mapping frameworks only display data in the Web Mercator projection. And I’d love to see more online slippy maps using such experimental projections. But I think it’s worth showing here because there isn’t much info out there on using custom (that is, outside of PROJ.4) projections in OpenLayers. Since Buckminster Fuller, Robert Gray, and Mike Bostock have already done all the hard work, adding the projection to OpenLayers is a cinch. In this post I just show how their JavaScript Dymaxion code can be brought into OpenLayers as a custom projection. But I hadn’t seen a client-side implementation until I saw this map in the examples section of Jeff Heer and Mike Bostock’s excellent JavaScript visualization framework Protovis. Erle’s modules were based on Robert Gray’s foundational work in determining the appropriate transformation equations which were then incorporated into C source code. I’ve seen a few code implementations of Bucky’s design over the years, including the Perl scripts Schuyler Erle wrote for his touchstone Mapping Hacks. Fuller intended the projection to better balance shape and areal distortion, while also eschewing the north-south cultural bias he saw in common projections. The most well-known, icosahedral form of the projection (above) was devised in Raleigh, North Carolina, in 1954. The great Buckminster Fuller created a series of Dymaxion maps utilizing various forms of his patented Fuller projection in the 1940s and 50s. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |