Install

Build it with:

make

Run tests with:

make check

On Windows

You need to have GEOS installed, let's say it was installed to C:\cygwin\opt\couchbase.

Open a shell which has all compilers and the MSVC environment set up (e.g. the Windows SDK 7.1 Command Prompt).

Now set it up so that GEOS and Erlang can be found:

SET INCLUDE=%INCLUDE%;C:\cygwin\opt\couchbase\include
SET LIB=%LIB%;C:\cygwin\opt\couchbase\lib
SET PATH=%PATH%;C:\cygwin\opt\couchbase\bin;C:\erl5.9.1\bin

And finally compile the whole thing:

rebar compile

Examples

Here's an example session in the erlang shell. See the src/erlgeom.erl file for more examples.

$ erl -pa ebin
Erlang R14B03 (erts-5.8.4) [source] [64-bit] [smp:4:4] [rq:4] [async-threads:0] [kernel-poll:false]

Eshell V5.8.4  (abort with ^G)

1> Geom1 = erlgeom:to_geom({'LineString', [[3,3],[10,10]]}),
1> Geom2 = erlgeom:to_geom({'LineString', [[1,1],[7,7]]}),
1> erlgeom:intersects(Geom1, Geom2).
true

2> Geom1 = erlgeom:to_geom({'LineString', [[3,3],[10,10]]}),
2> Geom2 = erlgeom:to_geom({'LineString', [[1,1],[7,7]]}),
2> Geom3 = erlgeom:intersection(Geom1, Geom2),
2> erlgeom:from_geom(Geom3).
{'LineString', [[3,3],[7,7]]}

3> WktReader = erlgeom:wktreader_create(),
3> Geom2 = erlgeom:wktreader_read(WktReader, 
3>    "POLYGON((0 0, 1 1, 1 2, 1 1, 0 0))"),
3> erlgeom:is_valid(Geom2).
false

4> Geom1 = erlgeom:to_geom({'LineString', [[4,4],[10,10]]}),
4> Geom2 = erlgeom:get_centroid(Geom1),
4> erlgeom:from_geom(Geom2).
{'Point',[7.0,7.0]}

5> Geom1 = erlgeom:to_geom({'LineString', [[4,4], [4.5, 4.5], [10,10]]}),
5> erlgeom:topology_preserve_simplify(Geom1, 1).
{'LineString',[[4.0,4.0],[10.0,10.0]]}

6> Geom1 = erlgeom:to_geom({'LineString', [[4,4], [4.5, 4.5], [10,10]]}),
6> erlgeom:is_valid(Geom1).
true

7> WktReader = erlgeom:wktreader_create(),
7> Geom = erlgeom:wktreader_read(WktReader, "POINT(10 10)"),
7> erlgeom:from_geom(Geom).
{'Point',[10.0,10.0]}

8> WktReader = erlgeom:wktreader_create(),
8> Geom = erlgeom:wktreader_read(WktReader, "POINT(10.0 10.0)"),
8> WkbWriter = erlgeom:wkbwriter_create(),
8> Bin = erlgeom:wkbwriter_write(WkbWriter, Geom),
8> WkbReader = erlgeom:wkbreader_create(),
8> Geom2 = erlgeom:wkbreader_read(WkbReader, Bin),
8> erlgeom:from_geom(Geom2).
{'Point',[10.0,10.0]}

9> WkbReader = erlgeom:wkbreader_create(),
9> Geom = erlgeom:wkbreader_readhex(WkbReader,
9>     "010100000000000000000024400000000000002440"),
9> erlgeom:from_geom(Geom).
{'Point',[10.0,10.0]}

10> WktReader = erlgeom:wktreader_create(),
10> Geom = erlgeom:wktreader_read(WktReader, "POINT(10 10)"),
10> WktWriter = erlgeom:wktwriter_create(),
10> erlgeom:wktwriter_write(WktWriter, Geom).
"Point(10.0000000000000000 10.0000000000000000)"

11> WktReader = erlgeom:wktreader_create(),
11> Geom = erlgeom:wktreader_read(WktReader, "POINT(10.0 10.0)"),
11> WkbWriter = erlgeom:wkbwriter_create(),
11> erlgeom:wkbwriter_write(WkbWriter, Geom).
<<1,1,0,0,0,0,0,0,0,0,0,36,64,0,0,0,0,0,0,36,64>>

12> WktReader = erlgeom:wktreader_create(),
12> Geom = erlgeom:wktreader_read(WktReader, "POINT(10.0 10.0)"),
12> WkbWriter = erlgeom:wkbwriter_create(),
12> erlgeom:wkbwriter_writehex(WkbWriter, Geom).
"010100000000000000000024400000000000002440"