CODEWITHSUNDEEP
swifthere-apiwms
Norman
Norman

Reputation: 51

Add a WMS Layer to Here Maps in Swift

I am trying to add a WMS Layer to Here Maps, but I do not find any starting point for doing that within their documentation...Also I did not find anything related to that here.

Has anyone expereience with WMS Layers in Here Map? So far I managed to work with WMS Layers in MapKit and OpenLayers. But the client is also interested in a HereMaps based approach.

My assumption is, that i need to setup the URL to my geoserver from here:

func mapTileLayer(_ mapTileLayer: NMAMapTileLayer, urlForTileAtX x: UInt, y: UInt, zoomLevel: UInt) -> String

But how can I transform x y to a bounding box?

Any help greatly appreciated!

Upvotes: 2

Views: 892

Answers (1)

lexicore
lexicore

Reputation: 43671

I have no idea about Swift, MapKit and Here Maps, so I'm best qualified to give an answer. :)
And here it is.

Since you're using a GeoServer, configure it to publish your layer as a WMTS/tile layer and use the tile set configuration which matches whatever you use in Here Maps (most probably Spherical Mercator/EPSG:900913). That should be more or less standard setting (last time I looked).

In this case it is trivial to create an URL from x, y and z, Will be just something like http://some-base.url/mygeoserver/.../${z}/${x}/${y}.png - something along the lines.

You can also turn on tile caching and pre-render tiles on upper zoom levels for better performance.

If you for some reason can't or don't want to configure the tile layer, I'd like to know the reason. :)

In this case you still can calculate the bounding box for your tiles coordinates. See the following links:

http://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/ https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Tile_bounding_box

To quote the OSM Wiki:

func tileToLatLon(tileX : Int, tileY : Int, mapZoom: Int) -> (lat_deg : Double, lon_deg : Double) {
    let n : Double = pow(2.0, Double(mapZoom))
    let lon = (Double(tileX) / n) * 360.0 - 180.0
    let lat = atan( sinh (.pi - (Double(tileY) / n) * 2 * Double.pi)) * (180.0 / .pi)

    return (lat, lon)
}

That results in EPSG:4326. If you need a different coordinate system, things get much more complicated.

Also you target coordinate system must "match" the original coordinate system in a sense that the resulting bounding box is not "rotated".

Upvotes: 1

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