1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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2 | * full list of contributors). Published under the Clear BSD license. |
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3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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4 | * full text of the license. */ |
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5 | |
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6 | /** |
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7 | * @requires OpenLayers/Control.js |
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8 | */ |
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9 | |
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10 | /** |
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11 | * Class: OpenLayers.Control.Graticule |
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12 | * The Graticule displays a grid of latitude/longitude lines reprojected on |
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13 | * the map. |
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14 | * |
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15 | * Inherits from: |
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16 | * - <OpenLayers.Control> |
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17 | * |
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18 | */ |
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19 | OpenLayers.Control.Graticule = OpenLayers.Class(OpenLayers.Control, { |
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20 | |
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21 | /** |
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22 | * APIProperty: autoActivate |
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23 | * {Boolean} Activate the control when it is added to a map. Default is |
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24 | * true. |
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25 | */ |
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26 | autoActivate: true, |
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27 | |
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28 | /** |
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29 | * APIProperty: intervals |
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30 | * {Array(Float)} A list of possible graticule widths in degrees. |
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31 | */ |
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32 | intervals: [ 45, 30, 20, 10, 5, 2, 1, |
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33 | 0.5, 0.2, 0.1, 0.05, 0.01, |
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34 | 0.005, 0.002, 0.001 ], |
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35 | |
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36 | /** |
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37 | * APIProperty: displayInLayerSwitcher |
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38 | * {Boolean} Allows the Graticule control to be switched on and off by |
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39 | * LayerSwitcher control. Defaults is true. |
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40 | */ |
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41 | displayInLayerSwitcher: true, |
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42 | |
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43 | /** |
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44 | * APIProperty: visible |
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45 | * {Boolean} should the graticule be initially visible (default=true) |
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46 | */ |
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47 | visible: true, |
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48 | |
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49 | /** |
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50 | * APIProperty: numPoints |
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51 | * {Integer} The number of points to use in each graticule line. Higher |
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52 | * numbers result in a smoother curve for projected maps |
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53 | */ |
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54 | numPoints: 50, |
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55 | |
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56 | /** |
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57 | * APIProperty: targetSize |
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58 | * {Integer} The maximum size of the grid in pixels on the map |
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59 | */ |
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60 | targetSize: 200, |
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61 | |
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62 | /** |
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63 | * APIProperty: layerName |
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64 | * {String} The name to be displayed in the layer switcher, default is set |
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65 | * by {<OpenLayers.Lang>}. |
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66 | */ |
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67 | layerName: null, |
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68 | |
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69 | /** |
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70 | * APIProperty: labelled |
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71 | * {Boolean} Should the graticule lines be labelled?. default=true |
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72 | */ |
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73 | labelled: true, |
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74 | |
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75 | /** |
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76 | * APIProperty: labelFormat |
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77 | * {String} the format of the labels, default = 'dm'. See |
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78 | * <OpenLayers.Util.getFormattedLonLat> for other options. |
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79 | */ |
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80 | labelFormat: 'dm', |
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81 | |
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82 | /** |
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83 | * APIProperty: lineSymbolizer |
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84 | * {symbolizer} the symbolizer used to render lines |
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85 | */ |
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86 | lineSymbolizer: { |
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87 | strokeColor: "#333", |
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88 | strokeWidth: 1, |
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89 | strokeOpacity: 0.5 |
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90 | }, |
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91 | |
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92 | /** |
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93 | * APIProperty: labelSymbolizer |
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94 | * {symbolizer} the symbolizer used to render labels |
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95 | */ |
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96 | labelSymbolizer: {}, |
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97 | |
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98 | /** |
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99 | * Property: gratLayer |
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100 | * {OpenLayers.Layer.Vector} vector layer used to draw the graticule on |
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101 | */ |
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102 | gratLayer: null, |
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103 | |
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104 | /** |
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105 | * Constructor: OpenLayers.Control.Graticule |
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106 | * Create a new graticule control to display a grid of latitude longitude |
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107 | * lines. |
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108 | * |
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109 | * Parameters: |
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110 | * options - {Object} An optional object whose properties will be used |
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111 | * to extend the control. |
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112 | */ |
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113 | initialize: function(options) { |
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114 | options = options || {}; |
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115 | options.layerName = options.layerName || OpenLayers.i18n("graticule"); |
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116 | OpenLayers.Control.prototype.initialize.apply(this, [options]); |
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117 | |
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118 | this.labelSymbolizer.stroke = false; |
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119 | this.labelSymbolizer.fill = false; |
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120 | this.labelSymbolizer.label = "${label}"; |
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121 | this.labelSymbolizer.labelAlign = "${labelAlign}"; |
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122 | this.labelSymbolizer.labelXOffset = "${xOffset}"; |
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123 | this.labelSymbolizer.labelYOffset = "${yOffset}"; |
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124 | }, |
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125 | |
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126 | /** |
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127 | * APIMethod: destroy |
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128 | */ |
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129 | destroy: function() { |
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130 | this.deactivate(); |
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131 | OpenLayers.Control.prototype.destroy.apply(this, arguments); |
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132 | if (this.gratLayer) { |
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133 | this.gratLayer.destroy(); |
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134 | this.gratLayer = null; |
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135 | } |
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136 | }, |
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137 | |
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138 | /** |
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139 | * Method: draw |
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140 | * |
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141 | * initializes the graticule layer and does the initial update |
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142 | * |
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143 | * Returns: |
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144 | * {DOMElement} |
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145 | */ |
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146 | draw: function() { |
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147 | OpenLayers.Control.prototype.draw.apply(this, arguments); |
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148 | if (!this.gratLayer) { |
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149 | var gratStyle = new OpenLayers.Style({},{ |
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150 | rules: [new OpenLayers.Rule({'symbolizer': |
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151 | {"Point":this.labelSymbolizer, |
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152 | "Line":this.lineSymbolizer} |
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153 | })] |
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154 | }); |
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155 | this.gratLayer = new OpenLayers.Layer.Vector(this.layerName, { |
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156 | styleMap: new OpenLayers.StyleMap({'default':gratStyle}), |
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157 | visibility: this.visible, |
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158 | displayInLayerSwitcher: this.displayInLayerSwitcher |
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159 | }); |
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160 | } |
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161 | return this.div; |
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162 | }, |
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163 | |
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164 | /** |
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165 | * APIMethod: activate |
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166 | */ |
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167 | activate: function() { |
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168 | if (OpenLayers.Control.prototype.activate.apply(this, arguments)) { |
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169 | this.map.addLayer(this.gratLayer); |
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170 | this.map.events.register('moveend', this, this.update); |
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171 | this.update(); |
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172 | return true; |
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173 | } else { |
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174 | return false; |
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175 | } |
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176 | }, |
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177 | |
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178 | /** |
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179 | * APIMethod: deactivate |
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180 | */ |
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181 | deactivate: function() { |
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182 | if (OpenLayers.Control.prototype.deactivate.apply(this, arguments)) { |
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183 | this.map.events.unregister('moveend', this, this.update); |
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184 | this.map.removeLayer(this.gratLayer); |
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185 | return true; |
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186 | } else { |
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187 | return false; |
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188 | } |
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189 | }, |
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190 | /** |
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191 | * Method: update |
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192 | * |
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193 | * calculates the grid to be displayed and actually draws it |
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194 | * |
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195 | * Returns: |
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196 | * {DOMElement} |
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197 | */ |
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198 | update: function() { |
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199 | //wait for the map to be initialized before proceeding |
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200 | var mapBounds = this.map.getExtent(); |
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201 | if (!mapBounds) { |
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202 | return; |
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203 | } |
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204 | |
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205 | //clear out the old grid |
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206 | this.gratLayer.destroyFeatures(); |
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207 | |
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208 | //get the projection objects required |
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209 | var llProj = new OpenLayers.Projection("EPSG:4326"); |
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210 | var mapProj = this.map.getProjectionObject(); |
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211 | var mapRes = this.map.getResolution(); |
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212 | |
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213 | //if the map is in lon/lat, then the lines are straight and only one |
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214 | //point is required |
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215 | if (mapProj.proj && mapProj.proj.projName == "longlat") { |
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216 | this.numPoints = 1; |
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217 | } |
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218 | |
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219 | //get the map center in EPSG:4326 |
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220 | var mapCenter = this.map.getCenter(); //lon and lat here are really map x and y |
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221 | var mapCenterLL = new OpenLayers.Pixel(mapCenter.lon, mapCenter.lat); |
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222 | OpenLayers.Projection.transform(mapCenterLL, mapProj, llProj); |
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223 | |
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224 | /* This block of code determines the lon/lat interval to use for the |
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225 | * grid by calculating the diagonal size of one grid cell at the map |
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226 | * center. Iterates through the intervals array until the diagonal |
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227 | * length is less than the targetSize option. |
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228 | */ |
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229 | //find lat/lon interval that results in a grid of less than the target size |
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230 | var testSq = this.targetSize*mapRes; |
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231 | testSq *= testSq; //compare squares rather than doing a square root to save time |
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232 | var llInterval; |
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233 | for (var i=0; i<this.intervals.length; ++i) { |
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234 | llInterval = this.intervals[i]; //could do this for both x and y?? |
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235 | var delta = llInterval/2; |
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236 | var p1 = mapCenterLL.offset(new OpenLayers.Pixel(-delta, -delta)); //test coords in EPSG:4326 space |
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237 | var p2 = mapCenterLL.offset(new OpenLayers.Pixel( delta, delta)); |
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238 | OpenLayers.Projection.transform(p1, llProj, mapProj); // convert them back to map projection |
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239 | OpenLayers.Projection.transform(p2, llProj, mapProj); |
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240 | var distSq = (p1.x-p2.x)*(p1.x-p2.x) + (p1.y-p2.y)*(p1.y-p2.y); |
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241 | if (distSq <= testSq) { |
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242 | break; |
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243 | } |
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244 | } |
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245 | //alert(llInterval); |
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246 | |
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247 | //round the LL center to an even number based on the interval |
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248 | mapCenterLL.x = Math.floor(mapCenterLL.x/llInterval)*llInterval; |
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249 | mapCenterLL.y = Math.floor(mapCenterLL.y/llInterval)*llInterval; |
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250 | //TODO adjust for minutses/seconds? |
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251 | |
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252 | /* The following 2 blocks calculate the nodes of the grid along a |
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253 | * line of constant longitude (then latitiude) running through the |
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254 | * center of the map until it reaches the map edge. The calculation |
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255 | * goes from the center in both directions to the edge. |
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256 | */ |
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257 | //get the central longitude line, increment the latitude |
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258 | var iter = 0; |
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259 | var centerLonPoints = [mapCenterLL.clone()]; |
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260 | var newPoint = mapCenterLL.clone(); |
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261 | var mapXY; |
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262 | do { |
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263 | newPoint = newPoint.offset(new OpenLayers.Pixel(0,llInterval)); |
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264 | mapXY = OpenLayers.Projection.transform(newPoint.clone(), llProj, mapProj); |
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265 | centerLonPoints.unshift(newPoint); |
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266 | } while (mapBounds.containsPixel(mapXY) && ++iter<1000); |
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267 | newPoint = mapCenterLL.clone(); |
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268 | do { |
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269 | newPoint = newPoint.offset(new OpenLayers.Pixel(0,-llInterval)); |
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270 | mapXY = OpenLayers.Projection.transform(newPoint.clone(), llProj, mapProj); |
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271 | centerLonPoints.push(newPoint); |
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272 | } while (mapBounds.containsPixel(mapXY) && ++iter<1000); |
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273 | |
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274 | //get the central latitude line, increment the longitude |
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275 | iter = 0; |
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276 | var centerLatPoints = [mapCenterLL.clone()]; |
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277 | newPoint = mapCenterLL.clone(); |
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278 | do { |
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279 | newPoint = newPoint.offset(new OpenLayers.Pixel(-llInterval, 0)); |
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280 | mapXY = OpenLayers.Projection.transform(newPoint.clone(), llProj, mapProj); |
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281 | centerLatPoints.unshift(newPoint); |
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282 | } while (mapBounds.containsPixel(mapXY) && ++iter<1000); |
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283 | newPoint = mapCenterLL.clone(); |
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284 | do { |
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285 | newPoint = newPoint.offset(new OpenLayers.Pixel(llInterval, 0)); |
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286 | mapXY = OpenLayers.Projection.transform(newPoint.clone(), llProj, mapProj); |
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287 | centerLatPoints.push(newPoint); |
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288 | } while (mapBounds.containsPixel(mapXY) && ++iter<1000); |
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289 | |
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290 | //now generate a line for each node in the central lat and lon lines |
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291 | //first loop over constant longitude |
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292 | var lines = []; |
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293 | for(var i=0; i < centerLatPoints.length; ++i) { |
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294 | var lon = centerLatPoints[i].x; |
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295 | var pointList = []; |
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296 | var labelPoint = null; |
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297 | var latEnd = Math.min(centerLonPoints[0].y, 90); |
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298 | var latStart = Math.max(centerLonPoints[centerLonPoints.length - 1].y, -90); |
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299 | var latDelta = (latEnd - latStart)/this.numPoints; |
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300 | var lat = latStart; |
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301 | for(var j=0; j<= this.numPoints; ++j) { |
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302 | var gridPoint = new OpenLayers.Geometry.Point(lon,lat); |
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303 | gridPoint.transform(llProj, mapProj); |
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304 | pointList.push(gridPoint); |
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305 | lat += latDelta; |
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306 | if (gridPoint.y >= mapBounds.bottom && !labelPoint) { |
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307 | labelPoint = gridPoint; |
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308 | } |
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309 | } |
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310 | if (this.labelled) { |
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311 | //keep track of when this grid line crosses the map bounds to set |
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312 | //the label position |
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313 | //labels along the bottom, add 10 pixel offset up into the map |
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314 | //TODO add option for labels on top |
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315 | var labelPos = new OpenLayers.Geometry.Point(labelPoint.x,mapBounds.bottom); |
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316 | var labelAttrs = { |
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317 | value: lon, |
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318 | label: this.labelled?OpenLayers.Util.getFormattedLonLat(lon, "lon", this.labelFormat):"", |
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319 | labelAlign: "cb", |
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320 | xOffset: 0, |
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321 | yOffset: 2 |
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322 | }; |
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323 | this.gratLayer.addFeatures(new OpenLayers.Feature.Vector(labelPos,labelAttrs)); |
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324 | } |
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325 | var geom = new OpenLayers.Geometry.LineString(pointList); |
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326 | lines.push(new OpenLayers.Feature.Vector(geom)); |
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327 | } |
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328 | |
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329 | //now draw the lines of constant latitude |
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330 | for (var j=0; j < centerLonPoints.length; ++j) { |
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331 | lat = centerLonPoints[j].y; |
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332 | if (lat<-90 || lat>90) { //latitudes only valid between -90 and 90 |
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333 | continue; |
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334 | } |
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335 | var pointList = []; |
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336 | var lonStart = centerLatPoints[0].x; |
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337 | var lonEnd = centerLatPoints[centerLatPoints.length - 1].x; |
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338 | var lonDelta = (lonEnd - lonStart)/this.numPoints; |
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339 | var lon = lonStart; |
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340 | var labelPoint = null; |
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341 | for(var i=0; i <= this.numPoints ; ++i) { |
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342 | var gridPoint = new OpenLayers.Geometry.Point(lon,lat); |
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343 | gridPoint.transform(llProj, mapProj); |
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344 | pointList.push(gridPoint); |
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345 | lon += lonDelta; |
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346 | if (gridPoint.x < mapBounds.right) { |
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347 | labelPoint = gridPoint; |
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348 | } |
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349 | } |
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350 | if (this.labelled) { |
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351 | //keep track of when this grid line crosses the map bounds to set |
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352 | //the label position |
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353 | //labels along the right, 30 pixel offset left into the map |
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354 | //TODO add option for labels on left |
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355 | var labelPos = new OpenLayers.Geometry.Point(mapBounds.right, labelPoint.y); |
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356 | var labelAttrs = { |
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357 | value: lat, |
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358 | label: this.labelled?OpenLayers.Util.getFormattedLonLat(lat, "lat", this.labelFormat):"", |
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359 | labelAlign: "rb", |
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360 | xOffset: -2, |
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361 | yOffset: 2 |
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362 | }; |
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363 | this.gratLayer.addFeatures(new OpenLayers.Feature.Vector(labelPos,labelAttrs)); |
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364 | } |
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365 | var geom = new OpenLayers.Geometry.LineString(pointList); |
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366 | lines.push(new OpenLayers.Feature.Vector(geom)); |
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367 | } |
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368 | this.gratLayer.addFeatures(lines); |
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369 | }, |
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370 | |
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371 | CLASS_NAME: "OpenLayers.Control.Graticule" |
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372 | }); |
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373 | |
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