webapp/django/contrib/gis/utils/ogrinspect.py - gerrit-attic - Git at Google

 """
 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
	"""
	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