Sorry, had problems with sending this. Gerd _____
From: Gerd Dowideit [mailto:[EMAIL PROTECTED] Sent: Sunday, June 17, 2007 1:58 PM To: '[email protected]' Subject: OpenLayers Beginners Questions Hi All, I am exploring OpenLayers since a few days and encounter typical beginners problems: 1. Trying to make use of "Class Documentation" (http://dev.openlayers.org/docs/overview-tree.html <blocked::http://dev.openlayers.org/docs/overview-tree.html> ): the docu is fine, but I do miss information about 'what each entry is good for' and brief examples about 'how to make use'. A list ordered by purpose of classes and functions would also be good. Is there such a list which I have not found yet? 2. Problem with "var pointLayer = new OpenLayers.Layer.Vector("Point Layer");" and similar (Line and Polygon): All draw controls seem to draw points and vertices south-east of where the mouse-click occurred by about 1/2 of the diameter of the drawn Point-Circle. That means all drawn features are miss-placed. Is this a bug or is it just that I do use the draw feature wrongly? Source attached below. The website is at this stage not public for administrative reasons; sorry. Cheers, Gerd __________-___________ <html> <head> <style type="text/css"> p { width: 512px; } #map { width: 100%; height: 100%; border: 3px solid gray; } #controlToggle li { list-style: none; } } </style> <script src="./lib/OpenLayers.js"></script> <script src="Labels.js"></script> <script type="text/javascript"> <!-- var map, mymouse; function init(){ // The Map map = new OpenLayers.Map('map', {controls: [new OpenLayers.Control.MouseDefaults()] , maxResolution: 'auto', numZoomLevels: 4, maxExtent: new OpenLayers.Bounds(463934.22,6881911.1,468114.22,6885091.1)}); // ================ Layers ============================== // The image Base Layer var topomap = new OpenLayers.Layer.Image( 'Topo Map', 'http://10.0.0.1/www/OL-2-4/Maroon.jpg', new OpenLayers.Bounds(463934.22,6881911.1,468114.22,6885091.1), new OpenLayers.Size(1313, 1001), options); map.addLayers([topomap]); // Drawing Layers var pointLayer = new OpenLayers.Layer.Vector("Point Layer"); map.addLayers([pointLayer]); var lineLayer = new OpenLayers.Layer.Vector("Line Layer"); map.addLayers([lineLayer]); var polygonLayer = new OpenLayers.Layer.Vector("Polygon Layer"); map.addLayers([polygonLayer]); markers = new OpenLayers.Layer.Markers("markers", options); map.addLayers([markers]); add_markers(); markers.setVisibility(false); //=================== Controls ================= map.addControl(new OpenLayers.Control.MousePosition()); map.addControl(new OpenLayers.Control.LayerSwitcher()); map.addControl( new OpenLayers.Control.PanZoomBar() ); // =================== Options ================== var options = {handlerOptions: {freehand: true}}; drawControls = { point: new OpenLayers.Control.DrawFeature(pointLayer, OpenLayers.Handler.Point), line: new OpenLayers.Control.DrawFeature(lineLayer, OpenLayers.Handler.Path,options), polygon: new OpenLayers.Control.DrawFeature(polygonLayer, OpenLayers.Handler.Polygon,options) }; for(var key in drawControls) { map.addControl(drawControls[key]); } //=================== Zoom to screen =================== map.zoomToMaxExtent(); } //==================================== Functions ============================== function toggleControl(element) { for(key in drawControls) { var control = drawControls[key]; if(element.value == key && element.checked) { control.activate(); } else { control.deactivate(); } } } function q11_is(thisform) { var Q1_1 with(thisform) { Q1_1=value if(Q1_1==0) { Q11_Answer.innerHTML= "<br><br>" } else if(Q1_1==1) { Q11_Answer.innerHTML= "<br><center><table cellpadding=5 border=1><tr><td>Tool</td><td>Purpose</td></tr><tr><td><img src='Nav_1.jpg'></td><td valign=top><b>Pan</b><br>North-South<br>East-West<br><br><b>Zoom</b><br>In<b r>OUT</td></tr><tr><td><img src='Nav_2.jpg'></td><td><b>Zoom</b> to Area<br>Shift + drag mouse<br><b>Pan</b><br>Drag with mouse</td></tr><tr><td colspan=2>Tool active when on light-blue background</td></tr><tr><td colspan=2>Default: <br><B>Pan</b> by dragging with mouse<br><b>Zoom In</b>: Double-click on map</td></tr></table></center><br>" } else if(Q1_1==2) { Q11_Answer.innerHTML= "<br>Click on <img src='img/layer-switcher-maximize.png'> at the right of the map and select/deselect layer(s).<br>" } else if(Q1_1==3) { Q11_Answer.innerHTML= "<br>Feature digitizing is in freehand mode by default. In freehand mode, the mouse is treated as a pen. Drawing begins on mouse down, continues with every mouse move, and ends with mouse up.<br><br>To turn freehand mode off, hold down the shift key while digitizing. With freehand mode off, one vertex is added with each click and double-clicks finish drawing. Freehand mode can be toggled on and off at any time while drawing.<br>" } } } // --> </script> </head> <body onload="init()" bgcolor=#ddf9f9> <table border=1 cellpadding=5 width=99%> <tr> <td colspan=2><center> <strong><font face="arial" size="5">Maroon Dam</font></strong></center> </td> </tr> <tr> <td width=70% height=370 valign=top> <div id="map"></div> </td> <td valign=top> <center><b>Help</b> <SELECT Name="Q1_1" onchange="return q11_is(this)"> <OPTION Value=0>Select a Topic</OPTION> <OPTION Value=1>Navigate</OPTION> <OPTION Value=2>Layers</OPTION> <OPTION Value=3>Draw</OPTION> </select> <br> </center> <span id="Q11_Answer"><br><br></span></font> <hr> <center><b>Drawing Options</b></center> <ul id="controlToggle"> <li> <input type="radio" name="type" value="none" id="noneToggle" onclick="toggleControl(this);" checked="checked" /> <label for="noneToggle">navigate</label> </li> <li> <input type="radio" name="type" value="point" id="pointToggle" onclick="toggleControl(this);" /> <label for="pointToggle">draw point</label> </li> <li> <input type="radio" name="type" value="line" id="lineToggle" onclick="toggleControl(this);" /> <label for="lineToggle">draw line</label> </li> <li> <input type="radio" name="type" value="polygon" id="polygonToggle" onclick="toggleControl(this);" /> <label for="polygonToggle">draw polygon</label> </li> </ul> <hr> </td> </tr> <tr> <td> <b> <img src="img/marker.png" width="15" alt="" border="0"> Research Projects <img src="img/marker-blue.png" width="15" alt="" border="0"> Student Projects, Field Study Sites<br> <img src="img/marker-gold.png" width="15" alt="" border="0"> Institutions &nbs p; <img src="img/marker-green.png" width="15" alt="" border="0"> Miscellanious </b> <hr> <center> <strong><font face="arial" color="#808080" size="-2"> School of Geography, Planning and Architecture, The University of Queensland </font></strong> </center> </td> <td> <b>Commands:</b> Click to ... <div style="background-color:#e3fdf8" onclick="add_labels()"> <center><b>add Lables</b></center></div> <div style="background-color:#edfe9c" onclick="markers.setVisibility(true)"> <center><b>show Markers</b></center></div> <div style="background-color:#edfe9c" onclick="markers.setVisibility(false)"> <center><b>hide Markers</b></center></div> </td> </tr> </table> </body> </html> ___________________________________________ Dr Gerd R Dowideit School of Geography, Planning and Architecture The University of Queensland Chamberlain Building, Room 508 phone (07) 3365 3538 (work) (07) 3289 2325 (home) e-mail: [EMAIL PROTECTED] ________________________________________________ Dr Gerd R Dowideit 10 Atanie Court Wights Mountain, QLD 4520 phone: (07) 3289 2325 e-mail: [EMAIL PROTECTED] ________________________________________________ Dr Gerd R Dowideit 10 Atanie Court Wights Mountain, QLD 4520 phone: (07) 3289 2325 e-mail: [EMAIL PROTECTED]
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