Load a raster from a service, then apply a function to it.
Use case
Raster functions allow processing operations that can be applied to one or more rasters on the fly. Functions can be applied to rasters that come from a service. 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
The raster function is applied automatically when the sample starts and the result is displayed.
How it works
Create the ImageServiceRaster referring to the image server URL.
Create the RasterFunction from a JSON string.
Set the raster argument with rasterFunction.setRaster(rasterName, imageServiceRaster).
Create a new Raster referring to the raster function.
Create a RasterLayer to visualize the computed raster.
Display the raster.
Relevant API
ImageServiceRaster
Raster
RasterFunction
RasterFunctionArguments
RasterLayer
About the data
The sample applies a hillshade function to a raster produced from the National Land Cover Database, NLCDLandCover2001. You can learn more about the hillshade function in the ArcMap documentation.
Additional information
The raster function computation happens locally on the client device.
Tags
function, layer, raster, raster function, service
Sample Code
RasterFunctionService.qml
Use dark colors for code blocksCopy
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// [WriteFile Name=RasterFunctionService, Category=Layers]// [Legal]// Copyright 2017 Esri.// Licensed under the Apache License, Version 2.0 (the "License");// you may not use this file except in compliance with the License.// You may obtain a copy of the License at// http://www.apache.org/licenses/LICENSE-2.0// Unless required by applicable law or agreed to in writing, software// distributed under the License is distributed on an "AS IS" BASIS,// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.// See the License for the specific language governing permissions and// limitations under the License.// [Legal]import QtQuick
import QtQuick.Controls
import Esri.ArcGISRuntime
import Esri.ArcGISExtras
Rectangle {
id: rootRectangleclip: truewidth: 800height: 600 readonly property url dataPath: {
Qt.platform.os === "ios" ?
System.writableLocationUrl(System.StandardPathsDocumentsLocation) + "/ArcGIS/Runtime/Data/raster/" :
System.writableLocationUrl(System.StandardPathsHomeLocation) + "/ArcGIS/Runtime/Data/raster/" }
MapView {
id: mapViewanchors.fill: parentComponent.onCompleted: {
// Set the focus on MapView to initially enable keyboard navigation forceActiveFocus();
}
Map {
// create a basemap from a tiled layer and add to the mapBasemap {
initStyle: Enums.BasemapStyleArcGISStreets
}
// create and add a raster layer to the mapRasterLayer {
// create the raster layer from an image service rasterImageServiceRaster {
id: imageServiceRasterurl: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/NLCDLandCover2001/ImageServer"// zoom to the extent of the raster once it's loadedonLoadStatusChanged: {
if (loadStatus === Enums.LoadStatusLoaded) {
const scale = 50000000;
mapView.setViewpointCenterAndScale(imageServiceRaster.serviceInfo.fullExtent.center, scale);
}
}
}
}
}
}
// Create a button to apply the raster functionRectangle {
id: buttonproperty bool pressed: falseanchors {
right: parent.right
bottom: parent.bottom
rightMargin: 20bottomMargin: 40 }
width: 45height: width
color: pressed ? "#959595" : "#D6D6D6"radius: 100border {
color: "#585858"width: 1 }
Image {
anchors {
centerIn: parent }
width: 26height: width
source: "qrc:/Samples/Layers/RasterFunctionService/RasterImageAnalysisHillshade.png" }
MouseArea {
anchors.fill: parentonPressed: button.pressed = trueonReleased: button.pressed = falseonClicked: applyRasterFunction()
}
}
functionapplyRasterFunction() {
if (!hillShadeJson.exists) {
console.log("JSON file for the raster function does not exist");
return;
}
//! [ImageServiceRaster Apply a raster function]// create raster functionconst rasterFunction = ArcGISRuntimeEnvironment.createObject("RasterFunction", {path: dataPath + "/hillshade_simplified.json"});
// get the argumentsconst rasterFunctionArguments = rasterFunction.arguments;
// set the raster rasterFunctionArguments.setRaster("raster", imageServiceRaster);
// create the raster from the raster functionconst raster = ArcGISRuntimeEnvironment.createObject("Raster", { rasterFunction: rasterFunction });
// create raster layer from rasterconst rasterLayer = ArcGISRuntimeEnvironment.createObject("RasterLayer", { raster: raster });
//! [ImageServiceRaster Apply a raster function]// add raster to map mapView.map.operationalLayers.clear();
//! [ImageServiceRaster qml add raster operational] mapView.map.operationalLayers.append(rasterLayer);
//! [ImageServiceRaster qml add raster operational] }
FileInfo {
id: hillShadeJsonurl: dataPath + "/hillshade_simplified.json" }
}