Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

Regarding the GeoJSON representation of a TIN, are there

  1. any specifications or
  2. existing implementations I may not be aware of?

You could probably hack one together using the multipolygon feature type, but this seems inefficient.

Generally speaking, I don't see any surface types (regular or irregular) represented in the GeoJSON world, is there any existing or upcoming work in this area?

share|improve this question
    
you could ask to the geojson mailing list: lists.geojson.org/listinfo.cgi/geojson-geojson.org –  julien Apr 4 '12 at 12:10
add comment

1 Answer 1

up vote 2 down vote accepted

There doesn't appear to be a GeoJSON spec out for TIN, but there is one for WKT. Basically, TIN is a synonym for MultiPolygon, and Triangle is a synonym for Polygon.

Thus a four node, two element TIN can be encoded with the WKT:

TIN Z (((0 0 0, 0 0 1, 0 1 0, 0 0 0)), ((0 0 0, 0 1 0, 1 1 0, 0 0 0)))

Which should translate to:

{"type":"TIN","coordinates":[[[[0,0,0],[0,0,1],[0,1,0],[0,0,0]]],[[[0,0,0],[0,1,0],[1,1,0],[0,0,0]]]]}

With the OGC WKT specification, each triangle has one linear ring, with four vertices. (Rant: a triangle has only one linear ring and three vertices, and I'm unsure why OGC ignored these facts before inflating the storage size).

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.