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
- Create a
RasterFunctionusing the path to a local raster function JSON file. - Set the raster function arguments as required by the function used.
- Use the raster function to create a new
Raster. - Set the raster to a
RasterLayerand display it in theMap.
Relevant API
- Raster
- RasterFunction
- RasterLayer
Offline Data
Read more about how to set up the sample's offline data here.
| 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
// [WriteFile Name=RasterFunctionFile, 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] #ifdef PCH_BUILD #include "pch.hpp" #endif // PCH_BUILD // sample headers #include "RasterFunctionFile.h" // ArcGIS Maps SDK headers #include "Basemap.h" #include "Envelope.h" #include "Error.h" #include "LayerListModel.h" #include "Map.h" #include "MapQuickView.h" #include "MapTypes.h" #include "Raster.h" #include "RasterFunction.h" #include "RasterFunctionArguments.h" #include "RasterLayer.h" #include "Viewpoint.h" // Qt headers #include <QFileInfo> #include <QStandardPaths> #include <QtCore/qglobal.h> using namespace Esri::ArcGISRuntime; // helper method to get cross platform data path namespace { QString defaultDataPath() { QString dataPath; #ifdef Q_OS_IOS dataPath = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation); #else dataPath = QStandardPaths::writableLocation(QStandardPaths::HomeLocation); #endif return dataPath; } } // namespace RasterFunctionFile::RasterFunctionFile(QQuickItem* parent /* = nullptr */): QQuickItem(parent), m_dataPath(defaultDataPath() + "/ArcGIS/Runtime/Data/raster/") { } void RasterFunctionFile::init() { // Register the map view for QML qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView"); qmlRegisterType<RasterFunctionFile>("Esri.Samples", 1, 0, "RasterFunctionFileSample"); } void RasterFunctionFile::componentComplete() { QQuickItem::componentComplete(); // get data path m_rasterPath = m_dataPath + "Shasta_Elevation.tif"; // find QML MapView component m_mapView = findChild<MapQuickView*>("mapView"); // Create a map using the imagery basemap m_map = new Map(BasemapStyle::ArcGISImageryStandard, this); // Add the Raster Layer m_raster = new Raster(m_rasterPath, this); RasterLayer* rasterLayer = new RasterLayer(m_raster, this); rasterLayer->setOpacity(0.5); connect(rasterLayer, &RasterLayer::doneLoading, this, &RasterFunctionFile::readyChanged); m_map->operationalLayers()->append(rasterLayer); // Set initial Extent Envelope env = geometry_cast<Envelope>(Envelope::fromJson("{\"spatialReference\": {\"latestWkid\": 3857, \"wkid\": 102100 },\"xmax\": -13591503.517810356,\"xmin\": -13606233.44023646,\"ymax\": 4982810.138527592,\"ymin\": 4971762.696708013}")); m_map->setInitialViewpoint(Viewpoint(env)); // Set map to map view m_mapView->setMap(m_map); } void RasterFunctionFile::applyRasterFunction() { // create raster function RasterFunction* rasterFunction = createRasterFunction(); // check for valid raster function if (!rasterFunction) return; // create the raster from the raster function Raster* raster = new Raster(rasterFunction, this); // create raster layer from raster RasterLayer* rasterLayer = new RasterLayer(raster, this); rasterLayer->setOpacity(0.5); // add raster to map m_map->operationalLayers()->clear(); m_map->operationalLayers()->append(rasterLayer); } RasterFunction* RasterFunctionFile::createRasterFunction() { // Check if the raster function json exists QFileInfo colorJson(m_dataPath + "/color.json"); if (!colorJson.exists()) return nullptr; // create a RasterFunction RasterFunction* rasterFunction = new RasterFunction(m_dataPath + "/color.json", this); // check for valid raster function if (!rasterFunction) return nullptr; // set the number of rasters required - 2 in this case rasterFunction->arguments()->setRaster("raster", m_raster); rasterFunction->arguments()->setRaster("raster", m_raster); return rasterFunction; } bool RasterFunctionFile::ready() const { return m_raster && m_raster->loadStatus() == LoadStatus::Loaded; }