Masking / clipping raster

JuanPeralta_ESRIES

I am working with the latest iOS SDK (100.11).

I have a web map with a raster layer. I also have an area of interest, which actually is a farm lot (irregular polygon) and I would like to mask/clip the raster with that geometry so the raster is only visible for the AOI. Any ideas where to start?

The image would look like this one: 

Thanks!

Ting

Hi Juan,

We are aware of this question and currently I'm drafting a reply. Runtime SDK iOS provides limited support for Raster Functions: https://developers.arcgis.com/ios/layers/add-raster-data/#create-a-raster-from-a-raster-function and it is possible to clip a raster with a raster function.

Update 210814:

According to our core team, currently Runtime only support rectangular clipping. If you would like to request the clip raster with polygon feature in the future version of Runtime, I'd like to pass along your request to @DiveshGoyal .

 

Meanwhile, if you want to try out clipping with a rectangular box, here is a snippet that might help.

func clipRasterJSONString() {
    let rasterFunctionJSON = """
    {
      "raster_function_arguments":
      {
        "minx":{"double":2250000,"type":"Raster_function_variable"},
        "miny":{"double":-4100000,"type":"Raster_function_variable"},
        "maxx":{"double":2350000,"type":"Raster_function_variable"},
        "maxy":{"double":-3900000,"type":"Raster_function_variable"},
        "dx":{"double":100000,"type":"Raster_function_variable"},
        "dy":{"double":100000,"type":"Raster_function_variable"},
        "raster":{"name":"raster","is_raster":true,"type":"Raster_function_variable"},
        "type":"Raster_function_arguments"
      },
      "raster_function":{"type":"Clip_function"},
      "type":"Raster_function_template"
    }
    """
    let rasterFunction = AGSRasterFunction.fromJSON(rasterFunctionJSON, error: nil) as! AGSRasterFunction
    if let rasterFunctionArguments = rasterFunction.arguments {
        let rasterNames = rasterFunctionArguments.rasterNames
        rasterFunctionArguments.setRaster(raster, withName: rasterNames.first!)
        let newRaster = AGSRaster(rasterFunction: rasterFunction)
        let newRasterLayer = AGSRasterLayer(raster: newRaster)
        mapView.map?.operationalLayers.add(newRasterLayer)
    } else {
        print("Clip raster failed")
    }
}

You can either define the clipping box in a local Raster Function JSON file or in a JSON string, as shown above. Then, create a new raster with the raster function and add the layer to the map.

 

Attached is a demo app for clipping a raster. Please see the reference doc for the raster function JSON template.

 

References:

- https://developers.arcgis.com/ios/layers/add-raster-data/#raster-functions-supported-by-arcgis-runtime

- https://developers.arcgis.com/documentation/common-data-types/raster-function-objects.htm#ESRI_SECTION1_5A27A22F451A4DFF99B16FB6A7A0636A 

- https://developers.arcgis.com/ios/api-reference/interface_a_g_s_raster_function.html

 

Demo App Raster Clipping.zip