Hi Josh
I have a web site that reads in JSON to create a layer of crops. This layer can
be modified. I then write out the geometry of the selected features. Here are
the code snippets:
//declare the format
var geojson_format = new OpenLayers.Format.GeoJSON();
//add the layer
crops = new OpenLayers.Layer.Vector("Crop areas",
{isBaseLayer: false,
style: crop_style,
extractAttributes: true });
crops.addFeatures(geojson_format.read(cropsresponse.responseText));
map.addLayer(crops);
map.zoomToExtent(crops.getDataExtent());
//Select, Draw and Modify controls - these are specific to the layer
controls = {
select: new OpenLayers.Control.SelectFeature(crops, {callbacks:
{'over':feature_info}}),
dpolygon: new
OpenLayers.Control.DrawFeature(crops,OpenLayers.Handler.Polygon),
modify: new OpenLayers.Control.ModifyFeature(crops),
delf: new OpenLayers.Control.SelectFeature(crops, {onSelect:
function(feature) {crops.destroyFeatures([feature])}})
//delf: new OpenLayers.Control.SelectFeature(crops, {onSelect:
function(feature) {feature.geometry.destroy();crops.eraseFeatures([feature])}})
};
for(var key in controls) {
map.addControl(controls[key]);
}
}
//write out the geometry into a div
function feature_info(feature) {
var html = "<ul>";
OpenLayers.Util.getElement('crop').innerHTML =
"<strong>ID:</strong>" + feature.attributes.prop0 + " <strong>Area:</strong>" +
(Math.round(feature.geometry.getArea() / 100) / 100).toString() + " Ha";
var json = geojson_format.write(feature);
json = json.replace(/,/g, ', ');
document.getElementById('comments').innerHTML = json;
}
Hope that gives you some starters.
regards,
Robert S.
>>> "Josh S." <[email protected]> 23/05/2009 5:07 a.m. >>>
I need to export the geometries of multiple polygons a user draws, my plan is
to use json to export the geometries to another .js I'm using. Any
tips/help/code would be great.
-Josh
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