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
RasterFunction
using 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
RasterLayer
and 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;
}