normanb / couchmaps

CouchDB and MapServer

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Overview

A simple wrapper around MapServer (http://mapserver.org/) to enable

• MapServer map files to be written in JSON and stored in CouchDB
• MapServer to be managed and run in an Erlang OTP supervision process
• GDAL CouchDB OGR driver to serve GeoJSON directly from CouchDB as a WFS or rendered through WMS

MapServer is an Open Source platform for publishing spatial data and interactive mapping applications to the web.

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Requirements

1. Couchbase trunk

https://github.com/couchbase/couchdb-manifest (I used the preview branch and set up rake / ruby using RVM)

(currently GeoCouch uses couch_file:flush which isn't in couchdb trunk yet)

GDAL OGR couchdb driver can perform client side filtering, however in ogrcouchdbtablelayer if couchdb isn't present then the error is written to stderr which causes MapServer to raise an error.

2. GDAL trunk

http://svn.osgeo.org/gdal/trunk

3. MapServer trunk with CouchDB wrapper

[email protected]:normanb/mapserver.git

browse here https://github.com/normanb/mapserver/tree/master/mapserver

Configure as follows

./configure --with-wms --with-wfs --with-wcs --with-gdal --with-ogr --with-proj --with-couchdb

4. Configuration

Edit config/couchmaps.ini and copy to local.d and add couchmaps ebin files to path

alternatively

mkdir $COUCH_HOME/build/lib/couchdb/plugins/couchmaps/ebin

and copy beam files there.

note: currently map files are writting to tmp, but this can be override with a mapserver section in the ini file

e.g.

[mapserver]

tmp = /myothertmp

6. Populate database

ogr2ogr -f couchdb -lco "UPDATE_PERMISSIONS=ALL" "couchdb:http://localhost:8000" bcpos_trails.shp

7. Create a database called mapserver

Add sample mapserver map

curl -X PUT --data-binary @sample.map http://localhost:8000/mapserver/_mapserv/sample.map

this will convert the sample.map in mapfile format to JSON.

Note you can lock down http client browsing of sample.map with a redirect in couchdb that will not affect server operation.

8. Test WFS GetCapabilities

http://host:8000/mapserver/_mapserv/sample.map?request=getcapabilities&service=wfs&version=1.0.0

10. Test WFS GetFeature

if using geocouch, then test directly first

curl "http://host:8000/bcpos_trails/_design/ogr_spatial/_spatial/spatial?bbox=-180,-90,180,90"

then

curl "http://host:8000/mapserver/_mapserv/sample.map?SERVICE=WFS&VERSION=1.0.0&REQUEST=getfeature&TYPENAME=BoulderOpenSpace&MAXFEATURES=100"

The geojson data in CouchDB (step 6) is now returned as GML

11. Test WMS GetMap

http://host:8000/mapserver/_mapserv/sample.map?REQUEST=GetMap&SERVICE=WMS&VERSION=1.1.1&LAYERS=BoulderOpenSpace&STYLES=&FORMAT=image/tiff&SRS=EPSG:4326&WIDTH=400&HEIGHT=300&BBOX=-105.54,39.9138,-105.072,40.2608

and open up the returned geotiff to see a rendering of the geojson data in (6).

couchmaps's Issues

is this already active? some practical use case?

hello Norman.

I cannot find more info about this tool than here, so I wonder if it is still active? some successful use case and code from which to start? it would be very very helpful.

I am managing a dataset of about 15 milion records about biodiversity, each record with more than 30 columns that I want to filter with user demands. With postGIS it is becoming really slow and we are wondering if GeoCouch could help us.

I wanna created several degree grids for the entire world and apply a point-in-polygon to get how many records are in each degree cell. I understand this can be done relatively fast by GeoCouch, but what really worries me is the performance on plotting these geometries on the webmapping app. As we will get back GeoJSONs... let's say 500 'simple' (just degree cells, 4 coords), this would block the browser? (javascript has to transform this json to vectorial data). Currently using postGIS I get back a 300Kb JSON containing 1200 geometries.

So the ideal would be to request Couchdb and get back a WMS image via MapServer...

thanks in advance,

Pere