1 | """ |
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2 | WMS controller for OGC Web Services (OWS). |
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3 | |
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4 | @author: Stephen Pascoe |
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5 | """ |
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6 | |
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7 | import re |
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8 | import math |
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9 | from cStringIO import StringIO |
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10 | from sets import Set |
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11 | from matplotlib.cm import get_cmap |
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12 | from pylons import request, response, c |
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13 | |
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14 | import logging |
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15 | log = logging.getLogger(__name__) |
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16 | |
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17 | import Image |
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18 | from genshi.template import NewTextTemplate |
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19 | |
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20 | from cows.model.wms import WmsDatasetSummary, Dimension |
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21 | from cows.model import PossibleValues, WGS84BoundingBox, BoundingBox, Contents |
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22 | from cows.pylons import ows_controller |
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23 | from cows.exceptions import * |
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24 | from cows import bbox_util |
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25 | |
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26 | class WMSController(ows_controller.OWSController): |
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27 | """ |
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28 | Subclass this controller in a pylons application and set the layerMapper |
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29 | class attribute to implement a WMS. |
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30 | |
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31 | @cvar layerMapper: an cows.service.wms_iface.ILayerMapper object. |
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32 | |
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33 | """ |
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34 | layerMapper = None |
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35 | #layers = {} |
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36 | _pilImageFormats = { |
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37 | 'image/png': 'PNG', |
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38 | 'image/jpg': 'JPEG', |
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39 | 'image/gif': 'GIF', |
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40 | 'image/tiff': 'TIFF' |
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41 | } |
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42 | _layerSlabCache = {} |
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43 | |
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44 | #------------------------------------------------------------------------- |
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45 | # Attributes required by OWSController |
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46 | |
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47 | service = 'WMS' |
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48 | owsOperations = (ows_controller.OWSController.owsOperations + |
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49 | ['GetMap', 'GetContext', 'GetLegend', 'GetFeatureInfo', 'GetInfo']) |
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50 | validVersions = ['1.1.1', '1.3.0'] |
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51 | |
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52 | #------------------------------------------------------------------------- |
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53 | |
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54 | def __before__(self, **kwargs): |
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55 | """ |
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56 | This default implementation of __before__() will pass all routes |
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57 | arguments to the layer mapper to retrieve a list of layers for |
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58 | this WMS. |
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59 | |
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60 | It will be called automatically by pylons before each action method. |
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61 | |
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62 | @todo: The layer mapper needs to come from somewhere. |
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63 | |
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64 | """ |
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65 | #self.updateSequence = "hello" |
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66 | print "loading layers" |
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67 | #print self.layers |
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68 | self.layers = self.layerMapper.map(**kwargs) |
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69 | |
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70 | #------------------------------------------------------------------------- |
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71 | # Methods implementing stubs in OWSController |
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72 | |
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73 | def _renderCapabilities(self, version, format): |
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74 | if format == 'application/json': |
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75 | t = ows_controller.templateLoader.load('wms_capabilities_json.txt', |
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76 | cls=NewTextTemplate) |
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77 | elif version == '1.1.1': |
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78 | t = ows_controller.templateLoader.load('wms_capabilities_1_1_1.xml') |
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79 | elif version == '1.3.0': |
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80 | t = ows_controller.templateLoader.load('wms_capabilities_1_3_0.xml') |
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81 | else: |
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82 | # We should never get here! The framework should raise an exception before now. |
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83 | raise RuntimeError("Version %s not supported" % version) |
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84 | |
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85 | return t.generate(c=c).render() |
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86 | |
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87 | def _loadCapabilities(self): |
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88 | """ |
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89 | @note: Assumes self.layers has already been created by __before__(). |
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90 | |
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91 | """ |
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92 | ows_controller.addOperation('GetMap', formats=self._pilImageFormats.keys()) |
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93 | ows_controller.addOperation('GetContext') |
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94 | ows_controller.addOperation('GetLegend', |
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95 | formats=['image/png']) |
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96 | ows_controller.addOperation('GetInfo') |
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97 | |
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98 | featureInfoFormats = Set() |
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99 | |
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100 | log.debug('Loading capabilities contents') |
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101 | c.capabilities.contents = Contents() |
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102 | for layerName, layer in self.layers.items(): |
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103 | print layerName |
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104 | log.debug('Loading layer %s' % layerName) |
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105 | |
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106 | wgs84BBox = WGS84BoundingBox(layer.wgs84BBox[:2], |
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107 | layer.wgs84BBox[2:]) |
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108 | # Get CRS/BBOX pairs |
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109 | bboxObjs = [] |
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110 | for crs in layer.crss: |
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111 | bbox = layer.getBBox(crs) |
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112 | bboxObjs.append(BoundingBox(bbox[:2], bbox[2:], crs=crs)) |
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113 | # Get dimensions |
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114 | dims = {} |
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115 | for dimName, dim in layer.dimensions.items(): |
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116 | dimParam = self._mapDimToParam(dimName) |
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117 | dims[dimParam] = Dimension(valuesUnit=dim.units, |
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118 | unitSymbol=dim.units, |
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119 | possibleValues= |
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120 | PossibleValues.fromAllowedValues(dim.extent)) |
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121 | # Does the layer implement GetFeatureInfo? |
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122 | if layer.featureInfoFormats: |
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123 | queryable = True |
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124 | featureInfoFormats.union_update(layer.featureInfoFormats) |
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125 | else: |
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126 | queryable = False |
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127 | |
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128 | # Create the cows object |
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129 | ds = WmsDatasetSummary(identifier=layerName, |
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130 | titles=[layer.title], |
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131 | CRSs=layer.crss, |
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132 | wgs84BoundingBoxes=[wgs84BBox], |
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133 | boundingBoxes=bboxObjs, |
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134 | abstracts=[layer.abstract], |
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135 | dimensions=dims, |
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136 | queryable=queryable) |
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137 | |
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138 | # Stuff that should go in the capabilities tree eventually |
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139 | ds.legendSize = layer.legendSize |
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140 | ds.legendFormats = ['image/png'] |
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141 | |
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142 | c.capabilities.contents.datasetSummaries.append(ds) |
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143 | |
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144 | # Add this operation here after we have found all formats |
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145 | ows_controller.addOperation('GetFeatureInfo', |
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146 | formats = list(featureInfoFormats)) |
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147 | |
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148 | def _getLayerParamInfo(self, paramName='layers'): |
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149 | """ |
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150 | Retrieve the layers parameter enforcing the rule of only |
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151 | selecting one layer. |
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152 | |
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153 | @param paramName: Overrides the query string parameter name to |
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154 | look for. This is usefull for implementing GetFeatureInfo. |
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155 | |
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156 | """ |
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157 | layerName = self.getOwsParam(paramName) |
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158 | |
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159 | # Select the first layer if several are requested. |
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160 | # This plays nicer with mapClient. |
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161 | if ',' in layerName: |
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162 | #layerName = layerName.split(',')[0] |
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163 | raise InvalidParameterValue( |
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164 | 'Multi-layer GetLegend requests are not supported', 'layers') |
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165 | try: |
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166 | layerObj = self.layers[layerName] |
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167 | except KeyError: |
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168 | raise InvalidParameterValue('Layer %s not found' % layerName, |
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169 | paramName) |
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170 | |
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171 | return layerName, layerObj |
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172 | |
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173 | def _getLayerParam(self, paramName='layers'): |
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174 | """ |
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175 | Retrieve the layers parameter enforcing the rule of only |
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176 | selecting one layer. |
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177 | |
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178 | @param paramName: Overrides the query string parameter name to |
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179 | look for. This is usefull for implementing GetFeatureInfo. |
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180 | |
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181 | """ |
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182 | #print self.getOwsParam(paramName) |
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183 | layers = {} |
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184 | layerNames = self.getOwsParam(paramName) |
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185 | |
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186 | # Select the first layer if several are requested. |
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187 | # This plays nicer with mapClient. |
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188 | #if ',' in layerName: |
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189 | layerNames = layerNames.split(',') |
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190 | #raise InvalidParameterValue( |
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191 | # 'Multi-layer GetMap requests are not supported', 'layers') |
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192 | for layerName in layerNames: |
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193 | try: |
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194 | layerObj = self.layers[layerName] |
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195 | layers[layerName] = layerObj |
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196 | except KeyError: |
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197 | raise InvalidParameterValue('Layer %s not found' % layerName, |
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198 | paramName) |
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199 | |
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200 | #return layerName, layerObj |
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201 | return layers |
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202 | |
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203 | def _getFormatParam(self): |
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204 | format = self.getOwsParam('format', default='image/png') |
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205 | if format not in self._pilImageFormats: |
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206 | raise InvalidParameterValue( |
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207 | 'Format %s not supported' % format, 'format') |
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208 | |
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209 | return format |
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210 | |
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211 | _escapedDimNames = ['width', 'height', 'version', 'request', |
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212 | 'layers', 'styles', 'crs', 'srs', 'bbox', |
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213 | 'format', 'transparent', 'bgcolor', |
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214 | 'exceptions'] |
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215 | |
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216 | def _getDimValues(self, layerObj): |
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217 | dimValues = {} |
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218 | for dimName, dim in layerObj.dimensions.items(): |
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219 | defaultValue = dim.extent[0] |
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220 | escapedDimName=self._mapDimToParam(dimName) |
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221 | dimValues[escapedDimName] = self.getOwsParam(escapedDimName, |
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222 | default=defaultValue) |
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223 | return dimValues |
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224 | |
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225 | def _mapDimToParam(self, dimName): |
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226 | """ |
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227 | Dimension names might clash with WMS parameter names, making |
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228 | them inaccessible in WMS requests. This method maps a |
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229 | dimension name to a parameter name that appears in the |
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230 | capabilities document and WMS requests. |
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231 | |
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232 | """ |
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233 | if dimName.lower() in self._escapedDimNames: |
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234 | return dimName+'_dim' |
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235 | else: |
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236 | return dimName |
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237 | |
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238 | def _mapParamToDim(self, dimParam): |
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239 | """ |
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240 | Maps a dimension parameter name to it's real dimension name. |
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241 | |
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242 | @see: _mapDimToParam() |
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243 | |
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244 | """ |
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245 | try: |
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246 | dimName = re.match(r'(.*)_dim$', dimParam).group(1) |
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247 | if dimName.lower() in self._escapedDimNames: |
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248 | return dimName |
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249 | else: |
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250 | return dimParam |
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251 | except AttributeError: |
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252 | return dimParam |
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253 | |
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254 | |
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255 | def _retrieveSlab(self, layerObj, srs, dimValues, renderOpts): |
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256 | # Find the slab in the cache first |
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257 | cacheKey = layerObj.getCacheKey(srs, dimValues) |
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258 | |
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259 | slab = self._layerSlabCache.get(cacheKey) |
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260 | if slab is None: |
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261 | slab = layerObj.getSlab(srs, dimValues, renderOpts) |
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262 | if cacheKey is not None: |
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263 | self._layerSlabCache[cacheKey] = slab |
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264 | |
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265 | return slab |
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266 | |
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267 | #------------------------------------------------------------------------- |
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268 | # OWS Operation methods |
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269 | |
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270 | def GetMap(self): |
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271 | |
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272 | # Housekeeping |
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273 | version = self.getOwsParam('version', default=self.validVersions[0]) |
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274 | if version not in self.validVersions: |
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275 | raise InvalidParameterValue('Version %s not supported' % version, |
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276 | 'version') |
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277 | styles = self.getOwsParam('styles', default='') |
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278 | transparent = self.getOwsParam('transparent', default='FALSE') |
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279 | bgcolor = self.getOwsParam('bgcolor', default='0xFFFFFF') |
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280 | |
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281 | # Layer handling |
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282 | #layerName, layerObj = self._getLayerParam() |
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283 | layers = self._getLayerParam() |
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284 | # Coordinate parameters |
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285 | bbox = tuple(float(x) for x in self.getOwsParam('bbox').split(',')) |
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286 | width = int(self.getOwsParam('width')) |
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287 | height = int(self.getOwsParam('height')) |
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288 | |
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289 | if version == '1.1.1': |
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290 | srs = self.getOwsParam('srs') |
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291 | else: |
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292 | srs = self.getOwsParam('crs') |
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293 | |
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294 | #if srs not in layerObj.crss: |
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295 | # raise InvalidParameterValue('Layer %s does not support SRS %s' % (layerName, srs)) |
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296 | |
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297 | # Get format |
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298 | format = self.getOwsParam('format') |
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299 | if format not in self._pilImageFormats: |
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300 | raise InvalidParameterValue( |
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301 | 'Format %s not supported' % format, 'format') |
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302 | |
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303 | finalImg = Image.new('RGBA', (width, height), (0,0,0,0)) |
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304 | |
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305 | # Multiple Layers handling.. |
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306 | for layerName, layerObj in layers.iteritems(): |
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307 | if srs not in layerObj.crss: |
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308 | raise InvalidParameterValue('Layer %s does not support SRS %s' % (layerName, srs)) |
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309 | |
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310 | dimValues = self._getDimValues(layerObj) |
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311 | |
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312 | #now need to revert modified dim values (e.g. height_dim) back to dim values the layerMapper understands (e.g. height) |
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313 | restoredDimValues={} |
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314 | for dim in dimValues: |
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315 | restoredDim=self._mapParamToDim(dim) |
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316 | restoredDimValues[restoredDim]=dimValues[dim] |
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317 | |
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318 | #------------------------------------------------------- |
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319 | # The real work |
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320 | #!TODO: Minimum and maximum values |
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321 | |
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322 | slab = self._retrieveSlab(layerObj, srs, restoredDimValues, |
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323 | dict(minValue=0, maxValue=100)) |
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324 | |
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325 | # We must request a bbox within the layer's bbox. |
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326 | lbbox = layerObj.getBBox(srs) |
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327 | ibbox = bbox_util.intersection(bbox, lbbox) |
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328 | |
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329 | log.debug('bbox = %s' % (bbox,)) |
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330 | log.debug('lbbox = %s' % (lbbox,)) |
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331 | log.debug('ibbox = %s' % (ibbox,)) |
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332 | |
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333 | # If bbox is not within layerObj.bbox then we need to calculate the |
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334 | # pixel offset of the inner bbox, request the right width/height |
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335 | # and paste the image into a blank background |
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336 | if bbox == ibbox: |
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337 | img = slab.getImage(bbox, width, height) |
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338 | log.debug('slab image.size = %s' % (img.size,)) |
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339 | |
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340 | else: |
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341 | |
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342 | ix0, iy0 = bbox_util.geoToPixel(ibbox[0], ibbox[3], bbox, width, height, |
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343 | roundUpY=True) |
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344 | ix1, iy1 = bbox_util.geoToPixel(ibbox[2], ibbox[1], bbox, width, height, |
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345 | roundUpX=True) |
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346 | iw = ix1-ix0 |
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347 | ih = iy1-iy0 |
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348 | log.debug('Deduced inner image: %s, (%d x %d)' % ((ix0, iy0, ix1, iy1), iw, ih)) |
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349 | img1 = slab.getImage(ibbox, iw, ih) |
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350 | |
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351 | img = Image.new('RGBA', (width, height)) |
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352 | img.paste(img1, (ix0, iy0)) |
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353 | |
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354 | finalImg = Image.composite(finalImg, img, finalImg) |
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355 | |
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356 | |
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357 | |
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358 | |
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359 | # IE < 7 doesn't display the alpha layer right. Here we sniff the |
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360 | # user agent and remove the alpha layer if necessary. |
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361 | try: |
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362 | ua = request.headers['User-Agent'] |
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363 | except: |
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364 | pass |
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365 | else: |
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366 | if 'MSIE' in ua and 'MSIE 7' not in ua: |
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367 | finalImg = finalImg.convert('RGB') |
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368 | |
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369 | buf = StringIO() |
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370 | finalImg.save(buf, self._pilImageFormats[format]) |
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371 | |
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372 | response.headers['Content-Type'] = format |
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373 | response.write(buf.getvalue()) |
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374 | |
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375 | return request |
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376 | |
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377 | def GetContext(self): |
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378 | """ |
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379 | Return a WebMap Context document for a given set of layers. |
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380 | |
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381 | """ |
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382 | # Parameters |
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383 | layers = self.getOwsParam('layers', default=None) |
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384 | |
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385 | # Filter self.layers for selected layers |
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386 | if layers is not None: |
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387 | newLayerMap = {} |
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388 | for layerName in layers.split(','): |
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389 | try: |
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390 | newLayerMap[layerName] = self.layers[layerName] |
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391 | except KeyError: |
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392 | raise InvalidParameterValue('Layer %s not found' % layerName, |
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393 | 'layers') |
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394 | |
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395 | self.layers = newLayerMap |
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396 | |
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397 | # Automatically select the first bbox/crs for the first layer |
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398 | aLayer = self.layers.values()[0] |
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399 | crs = aLayer.crss[0] |
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400 | bb = aLayer.getBBox(crs) |
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401 | c.bbox = BoundingBox(bb[:2], bb[2:], crs) |
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402 | |
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403 | # Initialise as if doing GetCapabilities |
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404 | ows_controller.initCapabilities() |
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405 | self._loadCapabilities() |
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406 | |
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407 | response.headers['Content-Type'] = 'text/xml' |
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408 | t = ows_controller.templateLoader.load('wms_context_1_1_1.xml') |
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409 | return t.generate(c=c).render() |
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410 | |
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411 | def GetFeatureInfo(self): |
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412 | # Housekeeping |
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413 | version = self.getOwsParam('version', default=self.validVersions[0]) |
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414 | if version not in self.validVersions: |
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415 | raise InvalidParameterValue('Version %s not supported' % version, |
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416 | 'version') |
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417 | |
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418 | # Coordinate parameters |
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419 | bbox = tuple(float(x) for x in self.getOwsParam('bbox').split(',')) |
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420 | width = int(self.getOwsParam('width')) |
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421 | height = int(self.getOwsParam('height')) |
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422 | |
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423 | # Get pixel location |
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424 | i = int(self.getOwsParam('i')) |
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425 | j = int(self.getOwsParam('j')) |
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426 | |
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427 | # Translate to geo-coordinates |
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428 | x, y = bbox_util.pixelToGeo(i, j, bbox, width, height) |
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429 | #start preparing GetFeatureInfo response. Assumes "HTML" output format |
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430 | |
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431 | htmlResponse = "<html><body><p> <b>Feature Information about pixel position: "+self.getOwsParam('i')+","+self.getOwsParam('j')+"/geo position: "+str(x)+","+str(y) +"<b/></p>" |
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432 | |
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433 | |
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434 | layers = self._getLayerParam('query_layers') |
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435 | #Adjusts response for multiple layers |
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436 | if len(layers) > 1: |
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437 | htmlResponse = htmlResponse+" Multiple possible features found as follows:" |
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438 | |
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439 | htmlResponse = htmlResponse+"<ul>" |
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440 | |
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441 | format = self.getOwsParam('info_format', default='text/html') |
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442 | for layerName, layerObj in layers.iteritems(): |
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443 | print format |
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444 | print layerObj.title |
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445 | print layerObj.featureInfoFormats |
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446 | if format not in layerObj.featureInfoFormats: |
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447 | raise InvalidParameterValue('Layer %s does not support GetFeatureInfo in format %s' %(layerName, format), 'info_format') |
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448 | |
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449 | if version == '1.1.1': |
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450 | srs = self.getOwsParam('srs') |
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451 | else: |
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452 | srs = self.getOwsParam('crs') |
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453 | |
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454 | if srs not in layerObj.crss: |
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455 | raise InvalidParameterValue('Layer %s does not support SRS %s' % |
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456 | (layerName, srs)) |
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457 | |
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458 | # Dimension handling |
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459 | dimValues = {} |
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460 | for dimName, dim in layerObj.dimensions.items(): |
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461 | defaultValue = dim.extent[0] |
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462 | dimValues[dimName] = self.getOwsParam(dimName, default=defaultValue) |
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463 | |
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464 | htmlResponse = htmlResponse+"<li> Layer Name: "+layerName+" <br />" |
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465 | # Call the layer |
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466 | htmlResponse =htmlResponse+layerObj.getFeatureInfo(format, srs, (x, y), dimValues)+"</li>" |
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467 | |
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468 | htmlResponse = htmlResponse+"</ul></body></html>" |
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469 | |
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470 | response.headers['Content-Type'] = format |
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471 | response.write(htmlResponse) |
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472 | |
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473 | def GetLegend(self): |
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474 | """ |
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475 | Return an image of the legend. |
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476 | |
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477 | """ |
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478 | # Parameters |
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479 | layerName, layerObj = self._getLayerParamInfo() |
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480 | format = self._getFormatParam() |
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481 | |
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482 | img = layerObj.getLegendImage() |
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483 | |
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484 | buf = StringIO() |
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485 | img.save(buf, self._pilImageFormats[format]) |
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486 | |
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487 | response.headers['Content-Type'] = format |
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488 | response.write(buf.getvalue()) |
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489 | |
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490 | |
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491 | def GetInfo(self): |
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492 | from pprint import pformat |
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493 | request.headers['Content-Type'] = 'text/ascii' |
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494 | response.write('Some info about this service\n') |
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495 | for layer in model.ukcip02.layers: |
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496 | response.write('Layer %s: %s\n' % (layer, pformat(g.ukcip02_layers[layer].__dict__))) |
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497 | |
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498 | |
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