PROJ BINDINGS UPDATE NOTES

• I had to get a tetanus shot because of the rust on my C++ "skills."
• Currently hardcoded the WAF build script to use /opt/local/* for Proj.
• Tested against Proj 4.7.0 on MacOS X 10.5.
• Projection object constructor currently only accepts Proj4 strings.
• Transformation is currently "in-place," but this can be changed pretty easily.

Code Example

var srcProj = new geonode.Projection("+init=epsg:4326"); var dstProj = new geonode.Projection("+init=esri:54004")

sys.puts(srcProj.definition); // " +init=epsg:4326 +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0" sys.puts(dstProj.definition); // " +init=esri:54004 +proj=merc +lat_ts=0 +lon_0=0 +k=1.000000 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs +towgs84=0,0,0"

var myPoint = new geonode.Geometry("POINT(1 2)");

// transformation is "in-place" geonode.Projection.transform(srcProj, dstProj, myPoint);

sys.puts(myPoint.toWkt()); // "POINT (111319.4907932735659415 221194.0771677151496988)"

---

~ geonode ~

Bringing geography to node.js.

Example

var geonode = require("geonode");

var myPoint = new geonode.Geometry("POINT(1 2)");
sys.puts(myPoint.toWkt()); // "POINT (1.0000000000000000 2.0000000000000000)"

var myPolygon = new geonode.Geometry("POLYGON((0 0, 3 0, 3 3, 0 3, 0 0))");
sys.puts(myPolygon.contains(myPoint)); // "true"

Installation

$ git clone git://github.com/paulsmith/geonode.git
$ cd geonode
$ node-waf configure build

Prerequisites

• GEOS 3.1.x

TODO

In no particular order:

• Finish wrapping GEOS C API
  • Coordinate sequence functions
  • Geometry constructors
  • Some topology operations -- polygonize, line merge, etc.
  • WKB read/write
• R-Tree index (with asynchronous searches, inserts, updates, deletes)
• Prepared geometries for faster predicates (contains, intersects, within)
• GDAL OGR wrapper -- non-blocking reads from datasources
• Proj wrapper
• Better organized unit tests, more coverage
• GeoJSON read/write
• De-cargo-cult the C++, be more idiomatic
• Document API

More tk ...

-- Paul Smith

@paulsmith pauladamsmith.com