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Code Issues 32 Releases Wiki Activity

gis: added the beginnings of a maps module, for generating mapping framework JavaScript; cleaned up the sitemaps module and KML templates; added shortcuts module.

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git-svn-id: http://code.djangoproject.com/svn/django/branches/gis@6108 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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Justin Bronn 2007-09-12 13:04:33 +00:00
parent ceac9c9645
commit b74f5ef66f
11 changed files with 372 additions and 23 deletions
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0
django/contrib/gis/maps/__init__.py Normal file
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django/contrib/gis/maps/google/__init__.py Normal file
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"""
This module houses the GoogleMap object, used for generating
the needed javascript to embed Google Maps in a webpage.
Google(R) is a registered trademark of Google, Inc. of Mountain View, California.
Example:
* In the view:
return render_to_response('template.html', {'google' : GoogleMap(key="abcdefg")})
* In the template:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
{{ google.xhtml }}
<head>
<title>Google Maps via GeoDjango</title>
{{ google.style }}
{{ google.scripts }}
</head>
{{ google.body }}
<div id="{{ google.dom_id }}"></div>
</body>
</html>
Note: If you want to be more explicit in your templates, the following are
equivalent:
{{ google.body }} => "<body {{ google.onload }} {{ google.onunload }}>"
{{ google.xhtml }} => "<html xmlns="http://www.w3.org/1999/xhtml" {{ google.xmlns }}>"
{{ google.style }} => "<style>{{ google.vml_css }}</style>"
Explanation:
- The `xhtml` property provides the correct XML namespace needed for
Google Maps to operate in IE using XHTML. Google Maps on IE uses
VML to draw polylines. Returns, by default:
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml">
- The `style` property provides the correct style tag for the CSS
properties required by Google Maps on IE:
<style type="text/css">v\:* {behavior:url(#default#VML);}</style>
- The `scripts` property provides the necessary <script> tags for
including the Google Maps javascript, as well as including the
generated javascript.
- The `body` property provides the correct attributes for the
body tag to load the generated javascript. By default, returns:
<body onload="gmap_load()" onunload="GUnload()">
- The `id` property returns the DOM id for the map. Defaults to "map".
The following attributes may be set or customized in your local settings:
* GOOGLE_MAPS_API_KEY: String of your Google Maps API key. These are tied to
to a domain. May be obtained from http://www.google.com/apis/maps/
* GOOGLE_MAPS_API_VERSION (optional): Defaults to using "2.x"
* GOOGLE_MAPS_URL (optional): Must have a substitution ('%s') for the API
version.
"""
from django.contrib.gis.maps.google.gmap import GoogleMap
from django.contrib.gis.maps.google.zoom import GoogleZoom

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django/contrib/gis/maps/google/gmap.py Normal file
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from django.conf import settings
from django.template.loader import render_to_string
# The default Google Maps URL (for the API javascript)
# TODO: Internationalize for Japan, UK, etc.
GOOGLE_MAPS_URL='http://maps.google.com/maps?file=api&amp;v=%s&amp;key='
class GoogleMapException(Exception): pass
class GoogleMap(object):
"A class for generating Google Maps javascript."
# String constants
onunload = 'onunload="GUnload()"' # Cleans up after Google Maps
vml_css = 'v\:* {behavior:url(#default#VML);}' # CSS for IE VML
xmlns = 'xmlns:v="urn:schemas-microsoft-com:vml"' # XML Namespace (for IE VML).
def __init__(self, key=None, api_url=None, version=None,
center_lat=0.0, center_lon=0.0, zoom=1,
dom_id='map', load_func='gmap_load',
kml_urls=[], template='gis/google/js/google-map.js'):
# The Google Maps API Key defined in the settings will be used
# if not passed in as a parameter. The use of an API key is
# _required_.
if not key:
try:
self._key = settings.GOOGLE_MAPS_API_KEY
except AttributeError:
raise GoogleMapException, 'Google Maps API Key not found (try adding GOOGLE_MAPS_API_KEY to your settings).'
else:
self._key = key
# Getting the Google Maps API version, defaults to using the latest ("2.x"),
# this is not necessarily the most stable.
if not version:
try:
self._version = settings.GOOGLE_MAPS_API_VERSION
except AttributeError:
self._version = '2.x'
else:
self._version = version
# Can specify the API URL in the `api_url` keyword.
if not api_url:
try:
self._url = settings.GOOGLE_MAPS_URL % self._version
except AttributeError:
self._url = GOOGLE_MAPS_URL % self._version
else:
self._url = api_url
# Setting the DOM id of the map, the center lat/lon, the load function,
# and the zoom.
self.dom_id = dom_id
self.center_lat = center_lat
self.center_lon = center_lon
self.load_func = load_func
self.template = template
self.zoom = zoom
# Setting the parameters for the javascript template.
params = {'center_lat' : center_lat,
'center_lon' : center_lon,
'dom_id' : dom_id,
'kml_urls' : kml_urls,
'load_func' : load_func,
'zoom' : zoom,
}
self.js = render_to_string(template, params)
@property
def body(self):
"Returns HTML body tag for loading and unloading Google Maps javascript."
return '<body %s %s>' % (self.onload, self.onunload)
@property
def onload(self):
"Returns the `onload` HTML <body> attribute."
return 'onload="%s()"' % self.load_func
@property
def api_script(self):
"Returns the <script> tag for the Google Maps API javascript."
return '<script src="%s%s" type="text/javascript"></script>' % (self._url, self._key)
@property
def scripts(self):
"Returns all <script></script> tags required for Google Maps JavaScript."
return '%s\n <script type="text/javascript">\n//<![CDATA[\n%s//]]>\n </script>' % (self.api_script, self.js)
@property
def style(self):
"Returns additional CSS styling needed for Google Maps on IE."
return '<style type="text/css">%s</style>' % self.vml_css
@property
def xhtml(self):
"Returns XHTML information needed for IE VML overlays."
return '<html xmlns="http://www.w3.org/1999/xhtml" %s>' % self.xmlns

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django/contrib/gis/maps/google/zoom.py Normal file
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from django.contrib.gis.geos import GEOSGeometry, LinearRing, Polygon, Point
from django.contrib.gis.maps.google.gmap import GoogleMapException
from math import pi, sin, cos, log, exp, atan
# Constants used for degree to radian conversion, and vice-versa.
DTOR = pi / 180.
RTOD = 180. / pi
def get_width_height(envelope):
# Getting the lower-left, upper-left, and upper-right
# coordinates of the envelope.
ll = Point(envelope[0][0])
ul = Point(envelope[0][1])
ur = Point(envelope[0][2])
height = ll.distance(ul)
width = ul.distance(ur)
return width, height
class GoogleZoom(object):
"""
GoogleZoom is a utility for performing operations related to the zoom
levels on Google Maps.
This class is inspired by the OpenStreetMap Mapnik tile generation routine
`generate_tiles.py`, and the article "How Big Is the World" (Hack #16) in
"Google Maps Hacks" by Rich Gibson and Schuyler Erle.
`generate_tiles.py` may be found at:
http://trac.openstreetmap.org/browser/applications/rendering/mapnik/generate_tiles.py
"Google Maps Hacks" may be found at http://safari.oreilly.com/0596101619
"""
def __init__(self, num_zoom=19, tilesize=256):
"Initializes the Google Zoom object."
# Google's tilesize is 256x256, square tiles are assumed.
self._tilesize = tilesize
# The number of zoom levels
self._nzoom = num_zoom
# Initializing arrays to hold the parameters for each
# one of the zoom levels.
self._degpp = [] # Degrees per pixel
self._radpp = [] # Radians per pixel
self._npix = [] # 1/2 the number of pixels for a tile at the given zoom level
# Incrementing through the zoom levels and populating the
# parameter arrays.
z = tilesize # The number of pixels per zoom level.
for i in xrange(num_zoom):
# Getting the degrees and radians per pixel, and the 1/2 the number of
# for every zoom level.
self._degpp.append(z / 360.) # degrees per pixel
self._radpp.append(z / (2 * pi)) # radians per pixl
self._npix.append(z / 2) # number of pixels to center of tile
# Multiplying `z` by 2 for the next iteration.
z *= 2
def __len__(self):
"Returns the number of zoom levels."
return self._nzoom
def get_lon_lat(self, lonlat):
"Unpacks longitude, latitude from GEOS Points and 2-tuples."
if isinstance(lonlat, Point):
lon, lat = lonlat.coords
else:
lon, lat = lonlat
return lon, lat
def lonlat_to_pixel(self, lonlat, zoom):
"Converts a longitude, latitude coordinate pair for the given zoom level."
# Setting up, unpacking the longitude, latitude values and getting the
# number of pixels for the given zoom level.
lon, lat = self.get_lon_lat(lonlat)
npix = self._npix[zoom]
# Calculating the pixel x coordinate by multiplying the longitude
# value with with the number of degrees/pixel at the given
# zoom level.
px_x = round(npix + (lon * self._degpp[zoom]))
# Creating the factor, and ensuring that 1 or -1 is not passed in as the
# base to the logarithm. Here's why:
# if fac = -1, we'll get log(0) which is undefined;
# if fac = 1, our logarithm base will be divided by 0, also undefined.
fac = min(max(sin(DTOR * lat), -0.9999), 0.9999)
# Calculating the pixel y coordinate.
px_y = round(npix + (0.5 * log((1 + fac)/(1 - fac)) * (-1.0 * self._radpp[zoom])))
# Returning the pixel x, y to the caller of the function.
return (px_x, px_y)
def pixel_to_lonlat(self, px, zoom):
"Converts a pixel to a longitude, latitude pair at the given zoom level."
if len(px) != 2:
raise TypeError, 'Pixel should be a sequence of two elements.'
# Getting the number of pixels for the given zoom level.
npix = self._npix[zoom]
# Calculating the longitude value, using the degrees per pixel.
lon = (px[0] - npix) / self._degpp[zoom]
# Calculating the latitude value.
lat = RTOD * ( 2 * atan(exp((px[1] - npix)/ (-1.0 * self._radpp[zoom]))) - 0.5 * pi)
# Returning the longitude, latitude coordinate pair.
return (lon, lat)
def tile(self, lonlat, zoom):
"""
Returns a Polygon corresponding to the region represented by a fictional
Google Tile for the given longitude/latitude pair and zoom level. This
tile is used to determine the size of a tile at the given point.
"""
# The given lonlat is the center of the tile.
delta = self._tilesize / 2
# Getting the pixel coordinates corresponding to the
# the longitude/latitude.
px = self.lonlat_to_pixel(lonlat, zoom)
# Getting the lower-left and upper-right lat/lon coordinates
# for the bounding box of the tile.
ll = self.pixel_to_lonlat((px[0]-delta, px[1]-delta), zoom)
ur = self.pixel_to_lonlat((px[0]+delta, px[1]+delta), zoom)
# Constructing the Polygon, representing the tile and returning.
return Polygon(LinearRing(ll, (ll[0], ur[1]), ur, (ur[0], ll[1]), ll), srid=4326)
def get_zoom(self, geom):
"Returns the optimal Zoom level for the given geometry."
# Checking the input type.
if not isinstance(geom, GEOSGeometry) and geom.srid == 4326:
raise TypeError, 'get_zoom() expects a GEOS Geometry with an SRID of 4326.'
# Getting the envelope for the geometry, and its associated width, height
# and centroid.
env = geom.envelope
env_w, env_h = get_width_height(env)
center = env.centroid
for z in xrange(self._nzoom):
# Getting the tile at the zoom level.
tile = self.tile(center, z)
tile_w, tile_h = get_width_height(tile)
# When we span more than one tile, this is an approximately good
# zoom level.
if (env_w > tile_w) or (env_h > tile_h):
if z == 0:
raise GoogleMapException, \
'Geometry width and height should not exceed that of the Earth.'
return z-1
# Otherwise, we've zoomed in to the max.
return self._nzoom-1

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django/contrib/gis/maps/openlayers/__init__.py Normal file
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django/contrib/gis/shortcuts.py Normal file
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from django.http import HttpResponse
from django.template import loader
def render_to_kml(*args, **kwargs):
"Renders the response using the MIME type for KML."
return HttpResponse(loader.render_to_string(*args, **kwargs),
mimetype='application/vnd.google-earth.kml+xml kml')
def render_to_text(*args, **kwargs):
"Renders the response using the MIME type for plain text."
return HttpResponse(loader.render_to_string(*args, **kwargs),
mimetype='text/plain')

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django/contrib/gis/sitemaps.py
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from django.core import urlresolvers
from django.contrib.sitemaps import Sitemap
from django.contrib.gis.db.models.fields import GeometryField
from django.contrib.gis.shortcuts import render_to_kml
from django.db.models import get_model, get_models
from django.template.loader import get_template
from django.template import Context
from django.http import HttpResponse
kml_files = [('gis.school', 'location'),
('gis.district', 'boundary')]
class KMLSitemap(Sitemap):
"""
A minimal hook to
A minimal hook to produce KML sitemaps.
"""
def __init__(self, locations=None):
if locations is None:
@ -28,7 +23,6 @@ class KMLSitemap(Sitemap):
kwargs={'label':obj[0],
'field_name':obj[1]})
def _build_kml_sources():
"Make a mapping of all available KML sources."
ret = []
@ -45,18 +39,17 @@ def _build_kml_sources():
class KMLNotFound(Exception):
pass
def kml(request, label, field_name):
placemarks = []
klass = get_model(*label.split('.'))
if not klass:
raise KMLNotFound("You must supply a valid app.model label. Got %s" % label)
#FIXME: GMaps apparently has a limit on size of displayed kml files
# check if paginating w/ external refs (i.e. linked list) helps.
placemarks.extend(list(klass._default_manager.kml(field_name)[:100]))
#FIXME: other KML features?
t = get_template('gis/kml.xml')
c = Context({'places':placemarks})
return render_to_kml('gis/kml/placemarks.kml', {'places' : placemarks})
return HttpResponse(t.render(c), mimetype='application/vnd.google-earth.kml+xml')

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django/contrib/gis/templates/gis/google/js/google-map.js Normal file
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{% block vars %}var map;{% for kml_url in kml_urls %}var kml{{ forloop.counter }};{% endfor %}{% endblock %}
{% block functions %}{% endblock %}
{% block load %}function {{ load_func }}(){
if (GBrowserIsCompatible()) {
map = new GMap2(document.getElementById("{{ dom_id }}"));
map.addControl(new GSmallMapControl());
map.addControl(new GMapTypeControl());
map.setCenter(new GLatLng({{ center_lat }}, {{ center_lon }}), {{ zoom }});
{% for kml_url in kml_urls %}kml{{ forloop.counter }} = new GGeoXml("{{ kml_url }}");
map.addOverlay(kml{{ forloop.counter }});{% endfor %}
{% block load_extra %}{% endblock %}
}else {
alert("Sorry, the Google Maps API is not compatible with this browser.");
}
}
{% endblock %}

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django/contrib/gis/templates/gis/kml.xml
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<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.1">
{% for place in places %}
<Placemark>
<name>{{ place.name|escape }}</name>
<description>{{ place.description|escape }}</description>
{{ place.kml }}
</Placemark>
{% endfor %}
</kml>

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django/contrib/gis/templates/gis/kml/base.kml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/{% block kml_version %}2.1{% endblock %}">
<Document>{% block name %}{% endblock %}
{% block placemarks %}{% endblock %}
</Document>
</kml>

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django/contrib/gis/templates/gis/kml/placemarks.kml Normal file
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{% extends "gis/kml/base.kml" %}
{% block placemarks %}{% for place in places %}
<Placemark>
<name>{{ place.name|escape }}</name>
<description>{{ place.description|escape }}</description>
{{ place.kml }}
</Placemark>{% endfor %}{% endblock %}