Author: jbronn
Date: 2007-11-17 16:04:05 -0600 (Sat, 17 Nov 2007)
New Revision: 6688
Added:
django/branches/gis/django/contrib/gis/utils/ogrinspect.py
Modified:
django/branches/gis/django/contrib/gis/utils/__init__.py
Log:
gis: Added the `ogrinspect` module (via patch from tlp), which provides
utilities for the generation of GeoDjango models from OGR data sources as well
as generation of LayerMapping dictionaries.
Modified: django/branches/gis/django/contrib/gis/utils/__init__.py
===================================================================
--- django/branches/gis/django/contrib/gis/utils/__init__.py 2007-11-17
21:57:12 UTC (rev 6687)
+++ django/branches/gis/django/contrib/gis/utils/__init__.py 2007-11-17
22:04:05 UTC (rev 6688)
@@ -1,15 +1,19 @@
"""
This module contains useful utilities for GeoDjango.
"""
-
-# Importing LayerMapping and ogrinfo (will not be done if GDAL is not
-# installed)
+# Importing the utilities that depend on GDAL, if available.
from django.contrib.gis.gdal import HAS_GDAL
if HAS_GDAL:
from django.contrib.gis.utils.ogrinfo import ogrinfo, sample
- from django.contrib.gis.utils.layermapping import LayerMapping
+ from django.contrib.gis.utils.ogrinspect import mapping, ogrinspect
+ try:
+ # LayerMapping requires DJANGO_SETTINGS_MODULE to be set,
+ # so this needs to be in try/except.
+ from django.contrib.gis.utils.layermapping import LayerMapping
+ except:
+ pass
-# Importing GeoIP
+# Attempting to import the GeoIP class.
try:
from django.contrib.gis.utils.geoip import GeoIP
HAS_GEOIP = True
Added: django/branches/gis/django/contrib/gis/utils/ogrinspect.py
===================================================================
--- django/branches/gis/django/contrib/gis/utils/ogrinspect.py
(rev 0)
+++ django/branches/gis/django/contrib/gis/utils/ogrinspect.py 2007-11-17
22:04:05 UTC (rev 6688)
@@ -0,0 +1,125 @@
+"""
+ This module is for inspecting OGR data sources and generating either
+ models for GeoDjango and/or mapping dictionaries for use with the
+ LayerMapping utility.
+
+ Author: Travis Pinney
+"""
+
+# Requires GDAL to use.
+from django.contrib.gis.gdal import DataSource
+
+def mapping(data_source, geom_name='geom', layer_key=0):
+ """
+ Given a DataSource, generates a dictionary that may be used
+ for invoking the LayerMapping utility.
+
+ Keyword Arguments:
+ `geom_name` => The name of the geometry field to use for the model.
+
+ `layer_key` => The key for specifying which layer in the DataSource to
use;
+ defaults to 0 (the first layer). May be an integer index or a string
+ identifier for the layer.
+ """
+ if isinstance(data_source, basestring):
+ # Instantiating the DataSource from the string.
+ data_source = DataSource(data_source)
+ elif isinstance(data_source, DataSource):
+ pass
+ else:
+ raise TypeError('Data source parameter must be a string or a
DataSource object.')
+
+ # Creating the dictionary.
+ _mapping = {}
+
+ # Generating the field name for each field in the layer.
+ for field in data_source[layer_key].fields:
+ mfield = field.lower()
+ if mfield[-1:] == '_': mfield += 'field'
+ _mapping[mfield] = field
+ gtype = data_source[layer_key].geom_type
+ _mapping[geom_name] = str(gtype).upper()
+
+ return _mapping
+
+def ogrinspect(*args, **kwargs):
+ """
+ Given a data source (either a string or a DataSource object) and a string
+ model name this function will generate a GeoDjango model.
+
+ Keyword Arguments
+ `geom_name` => For specifying the model name for the Geometry Field.
+
+ `layer_key` => The key for specifying which layer in the DataSource to
use;
+ defaults to 0 (the first layer). May be an integer index or a string
+ identifier for the layer.
+
+ `srid` => The SRID to use for the Geometry Field. If it can be
determined,
+ the SRID of the datasource
+
+ Note: This routine calls the _ogrinspect() helper to do the heavy lifting.
+ """
+ return '\n'.join(s for s in _ogrinspect(*args, **kwargs))
+
+def _ogrinspect(data_source, model_name, geom_name='geom', layer_key=0,
srid=None):
+ """
+ Helper routine for `ogrinspect` that generates GeoDjango models
corresponding
+ to the given data source. See the `ogrinspect` docstring for more details.
+ """
+
+ # Getting the DataSource
+ if isinstance(data_source, str):
+ data_source = DataSource(data_source)
+ elif isinstance(data_source, DataSource):
+ pass
+ else:
+ raise TypeError('Data source parameter must be a string or a
DataSource object.')
+
+ yield '# This is an auto-generated Django model module created by
ogrinspect.'
+ yield 'from django.contrib.gis.db import models'
+ yield ''
+ yield 'class %s(models.Model):' % model_name
+
+ layer = data_source[layer_key]
+
+ for width, precision, field in zip(layer.field_widths,
layer.field_precisions, layer.fields):
+ feature = layer[0]
+ fld_type = feature[field].type_name
+ mfield = field.lower()
+
+ if mfield[-1:] == '_':
+ mfield += 'field'
+
+ if fld_type == 'Real':
+ yield ' %s = models.DecimalField(max_digits=%s,
decimal_places=%s)' % (mfield, width, precision)
+ elif fld_type == 'Integer':
+ yield ' %s = models.IntegerField()' % mfield
+ elif fld_type == 'String':
+ yield ' %s = models.CharField(max_length=%s)' % (mfield, width)
+ elif fld_type == 'Date':
+ yield ' %s = models.DateField()' % mfield
+ elif fld_type == 'DateTime':
+ yield ' %s = models.DateTimeField()' % mfield
+ elif fld_type == 'Time':
+ yield ' %s = models.TimeField()' % mfield
+ else:
+ raise Exception('Unknown field type %s in %s' % (fld_type, mfield))
+
+ # Getting the geometry type
+ gtype = layer.geom_type
+
+ # Setting up the SRID parameter string.
+ if srid is None:
+ srid = layer.srs.srid
+ if srid is None:
+ srid_str = 'srid=-1'
+ elif srid == 4326:
+ # WGS84 is the default.
+ srid_str = ''
+ else:
+ srid_str = 'srid=%s' % srid
+ else:
+ srid_str = 'srid=%s' % srid
+
+ yield ' %s = models.%s(%s)' % (geom_name, gtype.django, srid_str)
+ yield ' objects = models.GeoManager()'
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/django-updates?hl=en
-~----------~----~----~----~------~----~------~--~---
