app/django/contrib/gis/utils/ogrinfo.py
author Sverre Rabbelier <srabbelier@gmail.com>
Mon, 07 Sep 2009 20:07:58 +0200
changeset 2877 8bbdc95f87f8
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Fix miscaching of homepage Add system.getHostname() and system.getAppVersion() to the homepage key so that we do not use an wrong version.

"""
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