Let's assume that I have selected some features in QGIS. Now all the features in that vector layer already has some style applied to it.
Now, I want to apply some new style to the selected features. Is this possible in QGIS?
QGIS Feature Style – How to Apply New Style to Selected Features in QGIS
featuresqgisstyle
Related Solutions
I attacked the problem from a different direction. Instead of trying to make it work using clone() or addFeatures I ended up using the WKT method. It probably isn't the best solution to the problem but it works. Here is the code I am using now:
function createSelectedFeatureLayer(selectItems) {
//GET THE NAME OF THE LAYER TO SELECT FROM
var mLayer = map.getLayersBy('name', 'Test Stands 4thQ 2012' );
//SET A VARIABLE TO THE LAYERS FEATURE ARRAY
var layerFeatureArray = mLayer[0].features;
//SET UP A STYLE MAP FOR THE FEATURES WE ARE GOING TO CREATE
var vctrStyleMap = new OpenLayers.StyleMap({
fillColor: '#FF0000',
fillOpacity: 0.5,
strokeColor: '#FF0000',
strokeWidth: 2.5
});
//CREATE A NEW VARIABLE TO HOLD A WELL KNOWN TEXT OBJECT
wkt = new OpenLayers.Format.WKT();
//CREATE A NEW EMPTY VECTOR LAYER TO HOLD THE FEATURES WE WILL CREATE - ASSIGN THE STYLEMAP VARIABLE TO IT
vectors = new OpenLayers.Layer.Vector("Search Results", { styleMap: vctrStyleMap });
//ADD THE NEW EMPTY VECTOR LAYER TO THE MAP OBJECT
map.addLayer(vectors);
//selectItems IS AN ARRAY OF VALUES I AM MATCHING AGAINST - LOOP THROUGH THIS LIST
for (a = 0; a < selectItems.length; a++) {
//LOOP THROUGH THE FEATURES ARRAY FROM THE LAYER WE ARE SELECTING FROM
for (x = 0; x < layerFeatureArray.length; x++) {
//IF THE UID OF THE FEATURE FROM THE SELECTION LAYER MATCHES THE VALUE FROM THE INPUT ARRAY
if (layerFeatureArray[x].attributes['UID'] == selectItems[a]) {
//SET A VARIABLE TO THE FEATURE
var searchFeature = layerFeatureArray[x];
//SET A VARIABLE TO THE WELL KNOWN TEXT VALUE OF THE FEATURE OBJECT - WRITE IT!
var str = wkt.write(searchFeature);
//READ THE WELL KNOWN TEXT STRING AND ASSIGN IT TO THE features VARIABLE
var features = wkt.read(str);
//ADD THE FEATURE TO THE VECTOR LAYER WE CREATED EARLIER
vectors.addFeatures(features);
break;
}//END if
} //END feature array FOR LOOP
} //END selItems array FOR LOOP
vectors.redraw();//REDRAW THE LAYER
map.zoomToExtent(vectors.getDataExtent()); //ZOOM TO THE NEW LAYERS
map.setLayerZIndex(vectors, 100); //PUT THE SELECTION LAYER ON TOP
}
Best Answer
If you selected your features by some attribute, then simply set that as a rule for the style (under Layer Properties), or use the attribute to adjust the global style by using the data-driven capabilities of the style manager.
If you selection was just a bunch of features you selected by hand that have no common, defining attribute, then I suggest, since you have a need to style them differently, you create a new attribute and give it a value for your selected features and then do as above.