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# Copyright (c) 2003, 2004 by Intevation GmbH |
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# Authors: |
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# Jan-Oliver Wagner <[email protected]> |
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# Martin Schulze <[email protected]> |
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# |
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# This program is free software; you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 2 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program; if not, write to the Free Software |
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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|
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""" |
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Graphic Layer via OGC WMS. |
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|
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class WMSLayer: |
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__init__() |
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|
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LatLongBoundingBox() |
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BoundingBox() |
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|
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getFormat(format) |
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calcFormat(formats) |
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|
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GetMapImg(width, height, bbox) |
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|
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Requirements: |
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- PyOGCLib <http://www.sourceforge.net/projects/pyogclib> |
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|
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Requires the ogclib installed regularily on the system or checked out |
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next to the Thuban checkout. Or set the PYTHONPATH to the PyOGCLib |
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directory before starting Thuban. |
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|
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""" |
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|
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__version__ = "$Revision$" |
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# $Source$ |
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# $Id$ |
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|
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|
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from Thuban.Model.layer import BaseLayer |
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from Thuban.Model.resource import get_system_proj_file, EPSG_PROJ_FILE, \ |
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EPSG_DEPRECATED_PROJ_FILE |
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from Thuban.UI.common import ThubanBeginBusyCursor, ThubanEndBusyCursor |
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|
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from capabilities import WMSCapabilities |
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|
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from ogclib.WMSClient import WMSClient |
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|
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|
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def epsg_code_to_projection(epsg): |
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"""Find the projection for the given epsg code. |
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|
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epsg -- EPSG code as string |
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""" |
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proj_file, warnings = get_system_proj_file(EPSG_PROJ_FILE) |
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|
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for proj in proj_file.GetProjections(): |
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if proj.EPSGCode() == epsg: |
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return proj |
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proj_file, warnings = get_system_proj_file(EPSG_DEPRECATED_PROJ_FILE) |
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for proj in proj_file.GetProjections(): |
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if proj.EPSGCode() == epsg: |
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return proj |
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return None |
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|
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|
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class WMSLayer(BaseLayer): |
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""" |
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WMS Layer |
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|
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This layer incorporates all methods from the Thuban BaseLayer and |
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adds specific methods for operating with a WMS server. |
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""" |
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|
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def __init__(self, title, url): |
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"""Initializes the WMSLayer. |
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|
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title -- Title of this layer. |
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url -- URL of the WMS-Server wich must contain '?' |
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|
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If an error occured, self.error_msg is a string describing |
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the problem(s). Else, self.error_msg is None. |
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""" |
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BaseLayer.__init__(self, title, visible = True, projection = None) |
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self.url = url |
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self.bbox = None |
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self.latlonbbox = None |
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self.error_msg = None |
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self.layer_name = None |
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self.capabilities = None |
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|
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# Change the cursor to demonstrate that we're busy but working |
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ThubanBeginBusyCursor() |
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self.capabilities = WMSCapabilities(url) |
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ThubanEndBusyCursor() |
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|
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# name of the top layer of the remote map |
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foo = self.capabilities.getLayers() |
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if len(foo) == 0: |
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self.error_msg = _('No layers found in remote resource:\n'\ |
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'%s') % url |
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return |
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top_layer = foo[0] |
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self.layer_name = top_layer |
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|
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# first projection of the top layer |
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foo = self.capabilities.getLayerSRS(top_layer) |
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if len(foo) == 0: |
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self.error_msg = _('No LatLonBoundingBox found for top layer %s')\ |
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% top_layer |
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return |
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top_srs = foo[0] |
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|
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# BoundingBox of the top layer |
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bbox = self.capabilities.getLayerBBox(top_layer, top_srs) |
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if len(bbox) == 0: |
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self.error_msg = _('No BoundingBox found for layer %s and EPSG:')\ |
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% (top_layer, top_srs) |
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return |
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self.bbox = (float(bbox['minx']), |
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float(bbox['miny']), |
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float(bbox['maxx']), |
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float(bbox['maxy'])) |
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|
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# LatLonBox of the top layer |
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bbox = self.capabilities.getLayerLatLonBBox(top_layer) |
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self.latlonbbox = (float(bbox['minx']), |
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float(bbox['miny']), |
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float(bbox['maxx']), |
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float(bbox['maxy'])) |
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|
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# get projection |
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p = epsg_code_to_projection(top_srs) |
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self.SetProjection(p) |
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|
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if p is None: |
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self.error_msg = _('EPSG projection code %s not found!\n'\ |
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'Setting projection to "None".\n'\ |
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'Please set an appropriate projection yourself.'\ |
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% top_srs) |
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|
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# pre-determine the used format |
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self.wmsformat, self.format = \ |
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self.calcFormat(self.capabilities.getFormats()) |
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if self.wmsformat is None: |
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self.error_msg = \ |
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_('No supported image format found in remote resource') |
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return |
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|
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# get and set the title |
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self.SetTitle(self.capabilities.getTitle().encode('latin1', 'replace')) |
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|
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|
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def LatLongBoundingBox(self): |
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""" |
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Return the layer's bounding box in lat-lon |
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""" |
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return self.latlonbbox |
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|
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|
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def BoundingBox(self): |
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""" |
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Return the layer's bounding box in the intrinsic coordinate system |
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""" |
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return self.bbox |
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|
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|
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def getFormat(self, format): |
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""" |
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Return the image format for the render engine |
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|
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format -- format as returned by the WMS server |
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|
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If no mapping was found, None is returned. |
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|
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This routine uses a simple heuristic in order to find the |
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broken down image format to be used with the internal render |
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engine. |
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|
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An exception rule is implemented in order to not accept |
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image/wbmp or WBMP which refers to WAP bitmap format and is |
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not supported by the included render engine. |
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""" |
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fmap = {'png' : "PNG", |
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'jpeg': "JPEG", |
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'jpg' : "JPEG", |
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'tif' : "TIFF", |
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'gif' : "GIF", |
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'wbmp': None, |
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'bmp' : "BMP"} |
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|
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for f in fmap.keys(): |
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if format.lower().find(f) > -1: |
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return fmap[f] |
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return None |
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|
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|
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def calcFormat(self, formats): |
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""" |
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Calculate the preferred image format |
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|
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formats -- list of formates as returned by the WMS server |
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|
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The following priority is used: |
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- PNG |
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- JPEG |
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- TIFF |
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- GIF |
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- BMP |
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|
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If no matching format was found, None, None will be returned. |
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|
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An exception rule is implemented in order to not accept |
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image/wbmp or WBMP which refers to WAP bitmap format and is |
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not supported by the included render engine. |
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""" |
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prio = ['jpeg', 'bmp'] |
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for p in prio: |
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for f in formats: |
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if f.lower().find(p) > -1: |
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if f.lower().find('wbmp') == -1: |
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return f, self.getFormat(f) |
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return None, None |
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|
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|
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def GetMapImg(self, width, height, bbox): |
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""" |
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Retrieve a new map from the WMS server and return it |
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width -- width in pixel of the desired image |
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height -- height in pixel of the desired image |
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bbox -- array of min(x,y) max(x,y) in the given SRS |
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|
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SRS and used image format will be retrieved from within the |
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layer itself. |
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""" |
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bbox_dict = { 'minx': bbox[0], 'miny': bbox[1], |
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'maxx': bbox[2], 'maxy': bbox[3] } |
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|
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# Change the cursor to demonstrate that we're busy but working |
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ThubanBeginBusyCursor() |
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|
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wmsclient = WMSClient() |
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|
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epsg_id = int(self.GetProjection().EPSGCode()) |
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|
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wms_response = wmsclient.getMap(self.url, self.wmsformat, width, height, |
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epsg_id, bbox_dict, |
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[self.layer_name], version = self.capabilities.getVersion()) |
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ThubanEndBusyCursor() |
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return wms_response, self.format |
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