lizard-geo

Introduction

Store geo objects and manage imports. The app provides the basics for storing geographical entities. GeoObjects store the entities themselves and GeoObjectGroup groups the GeoObjects.

See also lizard-area and lizard-fewsnorm as examples.

Development installation

The first time, you'll have to run the bootstrap script to set up setuptools and buildout:

$> python bootstrap.py

And then run buildout to set everything up:

$> bin/buildout

Note that on Microsoft Windows it is called bin\buildout.exe.

You will have to re-run buildout when setup.py or buildout.cfg have been modified, for example directly by you or through an update of your working directory.

The current package is installed as a "development package", so changes in .py files are automatically available (just like with python setup.py develop).

The app lizard-area uses a SpatiaLite database, although this will probably be overwritten at the site level. The repository already contains a SpatiaLite database, so you should not need to create one yourself. In case you want to create a new SpatiaLite database, execute the following command:

$> spatialite lizard-area.db < init_spatialite-2.3.sql
spatialite lizard-area.db < init_spatialite-2.3.sql
SpatiaLite version ..: 2.3.0  Supported Extensions:
      - 'VirtualShape'        [direct Shapefile access]
      - 'VirtualText          [direct CSV/TXT access]
      - 'VirtualNetwork       [Dijkstra shortest path]
      - 'RTree'               [Spatial Index - R*Tree]
      - 'MbrCache'            [Spatial Index - MBR cache]
      - 'VirtualFDO'          [FDO-OGR interoperability]
      - 'SpatiaLite'          [Spatial SQL - OGC]
PROJ.4 version ......: Rel. 4.7.1, 23 September 2009
GEOS version ........: 3.1.0-CAPI-1.5.0

The above snippet assumes you already have installed SpatiaLite.

To create the database tables and fill them do:

$ bin/django syncdb

Several lizard packages use South to handle the creation of tables. The above command will inform you which packages have to be handled by South. For example, its output will contains messages such as these:

Not synced (use migrations):
 - lizard_geo
 - lizard_ui
(use ./manage.py migrate to migrate these)

You can create the tables for these packages, or using the South terminology, 'migrate' them, as follows:

$ bin/django migrate

Usage

Most of the time you want to extend GeoObject because extra fields are needed. When importing from a datasource, for instance a shape file, you can make a GeoObjectGroup for each import. The purpose for a GeoObjectGroup is that you can remove GeoObjects later by removing the GeoObjectGroups.

Note that you must use PostGIS 1.5 or newer in order to make spatial queries on the GeometryField. A spatial queryset is for example: GeoObject.objects.filter(geometry__distance_lte=(pnt, D(m=10))