--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/contrib/gis/utils/ogrinspect.py Tue Oct 14 16:00:59 2008 +0000
@@ -0,0 +1,225 @@
+"""
+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, Dane Springmeyer, & Justin Bronn
+"""
+from itertools import izip
+# Requires GDAL to use.
+from django.contrib.gis.gdal import DataSource
+from django.contrib.gis.gdal.field import OFTDate, OFTDateTime, OFTInteger, OFTReal, OFTString, OFTTime
+
+def mapping(data_source, geom_name='geom', layer_key=0, multi_geom=False):
+ """
+ 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.
+
+ `multi_geom` => Boolean (default: False) - specify as multigeometry.
+ """
+ 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
+ if multi_geom and gtype.num in (1, 2, 3): prefix = 'MULTI'
+ else: prefix = ''
+ _mapping[geom_name] = prefix + 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.
+
+ Usage:
+
+ >>> from django.contrib.gis.utils import ogrinspect
+ >>> ogrinspect('/path/to/shapefile.shp','NewModel')
+
+ ...will print model definition to stout
+
+ or put this in a python script and use to redirect the output to a new
+ model like:
+
+ $ python generate_model.py > myapp/models.py
+
+ # generate_model.py
+ from django.contrib.gis.utils import ogrinspect
+ shp_file = 'data/mapping_hacks/world_borders.shp'
+ model_name = 'WorldBorders'
+
+ print ogrinspect(shp_file, model_name, multi_geom=True, srid=4326,
+ geom_name='shapes', blank=True)
+
+ Required Arguments
+ `datasource` => string or DataSource object to file pointer
+
+ `model name` => string of name of new model class to create
+
+ Optional Keyword Arguments
+ `geom_name` => For specifying the model name for the Geometry Field.
+ Otherwise will default to `geom`
+
+ `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 is used.
+
+ `multi_geom` => Boolean (default: False) - specify as multigeometry.
+
+ `name_field` => String - specifies a field name to return for the
+ `__unicode__` function (which will be generated if specified).
+
+ `imports` => Boolean (default: True) - set to False to omit the
+ `from django.contrib.gis.db import models` code from the
+ autogenerated models thus avoiding duplicated imports when building
+ more than one model by batching ogrinspect()
+
+ `decimal` => Boolean or sequence (default: False). When set to True
+ all generated model fields corresponding to the `OFTReal` type will
+ be `DecimalField` instead of `FloatField`. A sequence of specific
+ field names to generate as `DecimalField` may also be used.
+
+ `blank` => Boolean or sequence (default: False). When set to True all
+ generated model fields will have `blank=True`. If the user wants to
+ give specific fields to have blank, then a list/tuple of OGR field
+ names may be used.
+
+ `null` => Boolean (default: False) - When set to True all generated
+ model fields will have `null=True`. If the user wants to specify
+ give specific fields to have null, then a list/tuple of OGR field
+ names may be used.
+
+ 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,
+ multi_geom=False, name_field=None, imports=True,
+ decimal=False, blank=False, null=False):
+ """
+ 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.')
+
+ # Getting the layer corresponding to the layer key and getting
+ # a string listing of all OGR fields in the Layer.
+ layer = data_source[layer_key]
+ ogr_fields = layer.fields
+
+ # Creating lists from the `null`, `blank`, and `decimal`
+ # keyword arguments.
+ def process_kwarg(kwarg):
+ if isinstance(kwarg, (list, tuple)):
+ return [s.lower() for s in kwarg]
+ elif kwarg:
+ return [s.lower() for s in ogr_fields]
+ else:
+ return []
+ null_fields = process_kwarg(null)
+ blank_fields = process_kwarg(blank)
+ decimal_fields = process_kwarg(decimal)
+
+ # Gets the `null` and `blank` keywords for the given field name.
+ def get_kwargs_str(field_name):
+ kwlist = []
+ if field_name.lower() in null_fields: kwlist.append('null=True')
+ if field_name.lower() in blank_fields: kwlist.append('blank=True')
+ if kwlist: return ', ' + ', '.join(kwlist)
+ else: return ''
+
+ # For those wishing to disable the imports.
+ if imports:
+ 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
+
+ for field_name, width, precision, field_type in izip(ogr_fields, layer.field_widths, layer.field_precisions, layer.field_types):
+ # The model field name.
+ mfield = field_name.lower()
+ if mfield[-1:] == '_': mfield += 'field'
+
+ # Getting the keyword args string.
+ kwargs_str = get_kwargs_str(field_name)
+
+ if field_type is OFTReal:
+ # By default OFTReals are mapped to `FloatField`, however, they
+ # may also be mapped to `DecimalField` if specified in the
+ # `decimal` keyword.
+ if field_name.lower() in decimal_fields:
+ yield ' %s = models.DecimalField(max_digits=%d, decimal_places=%d%s)' % (mfield, width, precision, kwargs_str)
+ else:
+ yield ' %s = models.FloatField(%s)' % (mfield, kwargs_str[2:])
+ elif field_type is OFTInteger:
+ yield ' %s = models.IntegerField(%s)' % (mfield, kwargs_str[2:])
+ elif field_type is OFTString:
+ yield ' %s = models.CharField(max_length=%s%s)' % (mfield, width, kwargs_str)
+ elif field_type is OFTDate:
+ yield ' %s = models.DateField(%s)' % (mfield, kwargs_str[2:])
+ elif field_type is OFTDateTime:
+ yield ' %s = models.DateTimeField(%s)' % (mfield, kwargs_str[2:])
+ elif field_type is OFTDate:
+ yield ' %s = models.TimeField(%s)' % (mfield, kwargs_str[2:])
+ else:
+ raise TypeError('Unknown field type %s in %s' % (fld_type, mfield))
+
+ # TODO: Autodetection of multigeometry types (see #7218).
+ gtype = layer.geom_type
+ if multi_geom and gtype.num in (1, 2, 3):
+ geom_field = 'Multi%s' % gtype.django
+ else:
+ geom_field = gtype.django
+
+ # Setting up the SRID keyword string.
+ if srid is None:
+ if layer.srs is None:
+ srid_str = 'srid=-1'
+ else:
+ srid = layer.srs.srid
+ if srid is None:
+ srid_str = 'srid=-1'
+ elif srid == 4326:
+ # WGS84 is already the default.
+ srid_str = ''
+ else:
+ srid_str = 'srid=%s' % srid
+ else:
+ srid_str = 'srid=%s' % srid
+
+ yield ' %s = models.%s(%s)' % (geom_name, geom_field, srid_str)
+ yield ' objects = models.GeoManager()'
+
+ if name_field:
+ yield ''
+ yield ' def __unicode__(self): return self.%s' % name_field