如何在OpenLayers中检查特定投影中的LonLat有效性

Question

I want to use the method isValidLonLat to check for coordinate validity.

Mostly, I insert the coordinates in EPSG:4326 projection, but the isValidLonLat method checks using the world bounds, that are in EPSG:900913.

For example:

map.isValidLonLat(new OpenLayers.LonLat(-8, 400)) // returns true

Maybe it should consider this as false, because the latitude is over 180º.

I know why it returns true. As I said before, I noticed that the check is made using the bounds in EPSG:900913.

The question is: Is there a way to tell the method that the check should be made using a given projection (here EPSG:4326)?

Thanks

Answer 1

You can convert you coordinates from EPSG:4326 to EPSG:900913 and then make the check. For this you can use the proj4js Library

See the example below:

var SourceProjection = new Proj4js.Proj('EPSG:4326');
var DestinationProjection = new Proj4js.Proj('EPSG:900913');

var Point = new Proj4js.Point(longitude, latitude);          
Proj4js.transform(SourceProjection, DestinationProjection, Point); 
map.isValidLonLat(new OpenLayers.LonLat(Point.x, Point.y));