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ArcGIS Runtime SDK for Qt

Raster function (file)

Sample Viewer View Sample on GitHub

Apply a raster function to a local raster file and display the output with a raster layer.

Use case

Raster functions allow processing operations that can be applied to one or more rasters on the fly. A land survey agency may apply hillshade and aspect functions to rasters with elevation data in order to better determine the topography of a landscape and to make further planning decisions.

How to use the sample

Load the sample to see a raster function applied to a raster.

How it works

  1. Create a RasterFunction using the path to a local raster function JSON file.
  2. Set the raster function arguments as required by the function used.
  3. Use the raster function to create a new Raster.
  4. Set the raster to a RasterLayer and display it in the Map.

Relevant API

  • Raster
  • RasterFunction
  • RasterLayer

Offline data

Link Local Location
Shasta.tif raster <userhome>/ArcGIS/Runtime/Data/raster/Shasta_Elevation.tif
color.json raster function <userhome>/ArcGIS/Runtime/Data/raster/color.json

About the data

The raster function in the provided JSON file blends a color image with a greyscale image (in this case, a raster image containing elevation data), to add a hillshade effect to the input raster.

Additional information

Learn more about raster functions in the ArcGIS Pro documentation.

Tags

analysis, function, image, layer, processing, raster, raster function, transformation

Sample Code

import QtQuick 2.6
import Esri.ArcGISRuntime 100.9
import Esri.ArcGISExtras 1.1

Rectangle {
    id: rootRectangle
    clip: true
    width: 800
    height: 600

    property real scaleFactor: 1
    property url dataPath: System.userHomePath + "/ArcGIS/Runtime/Data/raster"
    property url rasterPath: dataPath + "/Shasta_Elevation.tif"

    MapView {
        id: mapView
        anchors.fill: parent

        Map {
            BasemapImagery {}

            RasterLayer {
                id: rasterLayer
                opacity: 0.5

                Raster {
                    id: theRaster
                    path: rasterPath
                }
            }

            ViewpointExtent {
                Envelope {
                    json: {
                        "spatialReference": {
                            "latestWkid": 3857,
                            "wkid": 102100
                        },
                        "xmax": -13591503.517810356,
                        "xmin": -13606233.44023646,
                        "ymax": 4982810.138527592,
                        "ymin": 4971762.696708013
                    }
                }
            }
        }
    }

    // Create a button to apply the raster function
    Rectangle {
        id: button
        enabled: theRaster.loadStatus === Enums.LoadStatusLoaded
        property bool pressed: false

        anchors {
            right: parent.right
            bottom: parent.bottom
            rightMargin: 20 * scaleFactor
            bottomMargin: 40 * scaleFactor
        }

        width: 45 * scaleFactor
        height: width
        color: pressed ? "#959595" : "#D6D6D6"
        radius: 100
        border {
            color: "#585858"
            width: 1 * scaleFactor
        }

        Image {
            anchors {
                centerIn: parent
                verticalCenterOffset: -3 * scaleFactor
            }
            width: 26 * scaleFactor
            height: width
            source: "qrc:/Samples/Layers/RasterFunctionFile/color.png"
        }

        MouseArea {
            anchors.fill: parent
            onPressed: button.pressed = true
            onReleased: button.pressed = false
            onClicked: applyRasterFunction()
        }
    }

    //! [RasterFunctionFile qml raster from function]
    function applyRasterFunction() {
        // create raster function
        const rasterFunction = createRasterFunction();

        // check for valid raster function
        if (!rasterFunction)
            return;

        // create the raster from the raster function
        const raster = ArcGISRuntimeEnvironment.createObject("Raster", { rasterFunction: rasterFunction });

        // create raster layer from raster
        const newRasterLayer = ArcGISRuntimeEnvironment.createObject("RasterLayer", { raster: raster });
        newRasterLayer.opacity = 0.5;

        // add raster to map
        mapView.map.operationalLayers.clear();
        mapView.map.operationalLayers.append(newRasterLayer);
    }

    function createRasterFunction() {
        // Check if the raster function json exists
        if (!colorJson.exists)
          return;

        // create the raster function
        const rasterFunction = ArcGISRuntimeEnvironment.createObject("RasterFunction", {path: dataPath + "/color.json"});

        // check for valid raster function
        if (!rasterFunction)
          return;

        rasterFunction.arguments.setRaster("raster", theRaster);
        rasterFunction.arguments.setRaster("raster", theRaster);

        return rasterFunction;
    }

    FileInfo {
        id: colorJson
        url: dataPath + "/color.json"
    }
    //! [RasterFunctionFile qml raster from function]
}