app/django/contrib/gis/utils/ogrinfo.py
author Daniel Hans <Daniel.M.Hans@gmail.com>
Tue, 03 Nov 2009 00:50:23 +0100
changeset 3075 1e78db95e38a
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
getListContentForData function added to lists helper. It allows to manually set a list of entities which is to be displayed on the view. Previously, the only function was getListContent, but it retrived data on its own by a single query. The new function can be useful whenever it is impossible or very awkward to obtain entities in such a way (for example more sophisticated SQL statements). Additionally, the getListContent function is reconstructed so that it collects the data first and then calls getListContentForData.

"""
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):
    """
    Walks the available layers in the supplied `data_source`, displaying
    the fields for the first `num_features` features.
    """

    # Checking the parameters.
    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

# For backwards compatibility.
sample = ogrinfo