GeoCouch is a spatial extension for Apache CouchDB.
A working installation of CouchDB with corresponding source code. GeoCouch works best with the latest stable releases of CouchDB (must be >= 1.0.2).
git clone https://github.com/couchone/geocouch.git
cd geocouch
Note: Always replace <vanilla-couch> with the path to your CouchDB
source and <geocouch> with the location of the GeoCouch source.
Set the COUCH_SRC environment to the directory that contains the
CouchDB core source (<vanilla-couch>/src/couchdb/).
export COUCH_SRC=<vanilla-couch>/src/couchdb
Run "make" in your directory
make
Copy the configuration file for GeoCouch from
<geocouch>/etc/couchdb/local.d/ to
<vanilla-couch>/etc/couchdb/local.d/
cp <geocouch>/etc/couchdb/local.d/geocouch.ini <vanilla-couch>/etc/couchdb/local.d/
To make sure your installation is working also copy the Futon tests
over (from <geocouch>/share/www/script/test to
<vanilla-couch>/share/www/script/test):
cp <geocouch>/share/www/script/test/* <vanilla-couch>/share/www/script/test/
Add the test to <vanilla-couch>/share/www/script/test/couch_tests.js
loadTest("spatial.js");
loadTest("list_spatial.js");
loadTest("etags_spatial.js");
loadTest("multiple_spatial_rows.js");
loadTest("spatial_compaction.js");
loadTest("spatial_design_docs.js");
The compiled beam files from GeoCouch need to be in Erlang's path,
which can be set with the ERL_FLAGS environment variable:
export ERL_FLAGS="-pa <geocouch>/build"
If you run a dev instance with CouchDB's ./utils/run you can also
define it on startup:
ERL_FLAGS="-pa <geocouch>/build" <vanilla-couch>/utils/run
Create a database:
curl -X PUT http://127.0.0.1:5984/places
Add a Design Document with a spatial function:
curl -X PUT -d '{"spatial":{"points":"function(doc) {\n if (doc.loc) {\n emit({\n type: \"Point\",\n coordinates: [doc.loc[0], doc.loc[1]]\n }, [doc._id, doc.loc]);\n }};"}}' http://127.0.0.1:5984/places/_design/main
Put some data into it:
curl -X PUT -d '{"loc": [-122.270833, 37.804444]}' http://127.0.0.1:5984/places/oakland
curl -X PUT -d '{"loc": [10.898333, 48.371667]}' http://127.0.0.1:5984/places/augsburg
Make a bounding box request:
curl -X GET 'http://localhost:5984/places/_design/main/_spatial/points?bbox=0,0,180,90'
It should return:
{"update_seq":3,"rows":[
{"id":"augsburg","bbox":[10.898333,48.371667,10.898333,48.371667],"value":["augsburg",[10.898333,48.371667]]}
]}
function(doc) { if (doc.loc) { emit({ type: "Point", coordinates: [doc.loc[0], doc.loc[1]] }, [doc._id, doc.loc]); }};"
It uses the emit() from normal views. The key is a GeoJSON geometry, the value is any arbitrary JSON. All geometry types (even GemetryCollections) are supported.
If the GeoJSON geometry contains a bbox property it will be used instead
of calculating it from the geometry (even if it's wrong, i.e. is not
the actual bounding box).
A common problem when performing bounding box searches is the date
line/poles. As the bounding box follows the GeoJSON specification,
where the first two numbers are the lower left coordinate, the last
two numbers the upper right coordinate, it is easy to map it over the
date line/poles. The lower coordinate would have a higher value than
the upper one. Such a bounding box has a seems invalid at first
glance, but isn't. For example a bounding box like 110,-60,-30,15
would include Australia and South America, but not Africa.
GeoCouch operates on a plane and doesn't perform spherical
calculations. Therefore the bounds of the plane needs to be set
explicitly with the plane_bounds parameter. If bounding boxes are
flipped, a search across those bounds will be performed
automatically. Give it a try (with the same Design Document as
above). Insert some Documents:
curl -X PUT -d '{"loc": [17.15, -22.566667]}' http://127.0.0.1:5984/places/namibia
curl -X PUT -d '{"loc": [135, -25]}' http://127.0.0.1:5984/places/australia
curl -X PUT -d '{"loc": [-52.95, -10.65]}' http://127.0.0.1:5984/places/brasilia
And request only Australia and Brasilia:
curl -X GET 'http://localhost:5984/places/_design/main/_spatial/points?bbox=110,-60,-30,15&plane_bounds=-180,-90,180,90'
The result is as expected:
{"update_seq":6,"rows":[
{"id":"australia","bbox":[135,-25,135,-25],"value":["australia",[135,-25]]},
{"id":"brasilia","bbox":[-52.95,-10.65,-52.95,-10.65],"value":["brasilia",[-52.95,-10.65]]}
]}
The bounding with the same numbers, but different order
(-30,-60,110,15) would only return Namibia:
curl -X GET 'http://localhost:5984/places/_design/main/_spatial/points?bbox=-30,-60,110,15&plane_bounds=-180,-90,180,90'
{"update_seq":6,"rows":[
{"id":"namibia","bbox":[17.15,-22.566667,17.15,-22.566667],"value":["namibia",[17.15,-22.566667]]}
]}
GeoCouch supports List functions just as CouchDB does for Views. This way you can output any arbitrary format, e.g. GeoRSS.
As an example we output the points as WKT. Add a new Design Document
with an additional List function (the rest is the same as above). Make
sure you use the right _rev:
curl -X PUT -d '{"_rev": "1-121efc747b00743b8c7621ffccf1ac40", "lists": {"wkt": "function(head, req) {\n var row;\n while (row = getRow()) {\n send(\"POINT(\" + row.value[1].join(\" \") + \")\\n\");\n }\n};"}, "spatial":{"points":"function(doc) {\n if (doc.loc) {\n emit({\n type: \"Point\",\n coordinates: [doc.loc[0], doc.loc[1]]\n }, [doc._id, doc.loc]);\n }};"}}' http://127.0.0.1:5984/places/_design/main
Now you can request this List function as you would do for CouchDB,
though with a different Design handler (_spatial/_list instead of
_list ):
curl -X GET 'http://localhost:5984/places/_design/main/_spatial/_list/wkt/points?bbox=-180,-90,180,90'
The result is:
POINT(-122.270833 37.804444)
POINT(10.898333 48.371667)
POINT(17.15 -22.566667)
POINT(135 -25)
POINT(-52.95 -10.65)
Using List functions from Design Documents other than the one containing the Spatial functions is supported as well. This time we add the Document ID in parenthesis:
curl -X PUT -d '{"lists": {"wkt": "function(head, req) {\n var row;\n while (row = getRow()) {\n send(\"POINT(\" + row.value[1].join(\" \") + \") (\" + row.id + \")\\n\");\n }\n};"}}' http://127.0.0.1:5984/places/_design/listfunonly
curl -X GET 'http://localhost:5984/places/_design/listfunonly/_spatial/_list/wkt/main/points?bbox=-180,-90,180,90'
stale=ok is supported. The spatial index won't be rebuilt even if
new Documents were added. It works for normal spatial queries as well
as for the spatial List functions.
count is a boolean. count=true will only return the number of geometries
the query will return, not the geometry themselves.
curl -X GET 'http://localhost:5984/places/_design/main/_spatial/points?bbox=0,0,180,90'
{"count":1}
The API of GeoCouch's spatial indexes is similar to the one for the Views. Compaction of spatial indexes is per Design Document, thus:
curl -X POST 'http://localhost:5984/places/_design/main/_spatial/_compact' -H 'Content-Type: application/json'
To cleanup spatial indexes that are no longer in use (this is per database):
curl -X POST 'http://localhost:5984/places/_spatial_cleanup' -H 'Content-Type: application/json'
To get information about the spatial indexes of a certain Design
Document use the the _info handler:
curl -X GET 'http://localhost:5984/places/_design/main/_spatial/_info'