ogr_stream_iterator.sql

CREATE TABLE ogr_stream_template (fid integer, the_geom geometry, fields text[], integers int[], floats float[], texts text[]);

CREATE OR REPLACE FUNCTION ogr_stream_iterator(path text, layer_name text, srid integer)
  RETURNS SETOF ogr_stream_template
AS $$


import sys
sys.path.insert(1, '/usr/local/gis/lib/python2.7/site-packages')

import binascii

import osgeo.ogr
import osgeo.gdalconst

import osgeo.osr

spatialref = osgeo.osr.SpatialReference()
spatialref.ImportFromEPSG(srid)

ds = osgeo.ogr.Open(path, osgeo.gdalconst.GF_Read)

layer = ds.GetLayerByName(layer_name)

if not layer:
    raise StopIteration

transform = osgeo.osr.CoordinateTransformation(layer.GetSpatialRef(), spatialref)

feature_defn = layer.GetLayerDefn()
feature_fields = [
        (
            idx,
            feature_defn.GetFieldDefn(idx).GetName(),
            feature_defn.GetFieldDefn(idx).GetTypeName()
        ) for idx in range(feature_defn.GetFieldCount())
    ]

fields = [field_name for field_idx, field_name, field_type in feature_fields]

for feature in layer:

    integers = []
    floats = []
    texts = []
    the_geom = feature.GetGeometryRef().Clone()
    the_geom.Transform(transform)

    for field_idx, field_name, field_type in feature_fields:
        value = feature.GetField(field_idx)
        if field_type == 'Real':
            floats.append(value)
        if field_type == 'String':
            texts.append(value)
        if field_type == 'Integer':
            integers.append(value)

    yield {
            'fid': feature.GetFID(),
            'the_geom': binascii.b2a_hex(the_geom.ExportToWkb()),
            'fields': fields,
            'integers': integers,
            'floats': floats,
            'texts': texts,
        }

$$ LANGUAGE plpythonu;