| """ |
| This module includes some utility functions for inspecting the layout |
| of a GDAL data source -- the functionality is analogous to the output |
| produced by the `ogrinfo` utility. |
| """ |
|
|
| from django.contrib.gis.gdal import DataSource |
| from django.contrib.gis.gdal.geometries import GEO_CLASSES |
|
|
|
|
| def ogrinfo(data_source, num_features=10): |
| """ |
| Walk the available layers in the supplied `data_source`, displaying |
| the fields for the first `num_features` features. |
| """ |
|
|
| |
| if isinstance(data_source, str): |
| data_source = DataSource(data_source) |
| elif isinstance(data_source, DataSource): |
| pass |
| else: |
| raise Exception( |
| "Data source parameter must be a string or a DataSource object." |
| ) |
|
|
| for i, layer in enumerate(data_source): |
| print("data source : %s" % data_source.name) |
| print("==== layer %s" % i) |
| print(" shape type: %s" % GEO_CLASSES[layer.geom_type.num].__name__) |
| print(" # features: %s" % len(layer)) |
| print(" srs: %s" % layer.srs) |
| extent_tup = layer.extent.tuple |
| print(" extent: %s - %s" % (extent_tup[0:2], extent_tup[2:4])) |
| print("Displaying the first %s features ====" % num_features) |
|
|
| width = max(*map(len, layer.fields)) |
| fmt = " %%%ss: %%s" % width |
| for j, feature in enumerate(layer[:num_features]): |
| print("=== Feature %s" % j) |
| for fld_name in layer.fields: |
| type_name = feature[fld_name].type_name |
| output = fmt % (fld_name, type_name) |
| val = feature.get(fld_name) |
| if val: |
| if isinstance(val, str): |
| val_fmt = ' ("%s")' |
| else: |
| val_fmt = " (%s)" |
| output += val_fmt % val |
| else: |
| output += " (None)" |
| print(output) |
|
|
