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
Tap the "Apply Layer" button to apply the raster function and display the result.
How it works
Create the ImageServiceRaster referring to the image server URL.
Create the RasterFunction from a JSON string.
Get the arguments of the raster function with rasterFunction.getArguments().
Get the names of the raster arguments with rasterFunctionArguments.getRasterNames().
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
MainActivity.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
/* Copyright 2018 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.
*
*/package com.esri.arcgisruntime.sample.rasterfunctionservice;
import java.util.List;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.layers.RasterLayer;
import com.esri.arcgisruntime.loadable.LoadStatus;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.view.MapView;
import com.esri.arcgisruntime.raster.ImageServiceRaster;
import com.esri.arcgisruntime.raster.Raster;
import com.esri.arcgisruntime.raster.RasterFunction;
import com.esri.arcgisruntime.raster.RasterFunctionArguments;
publicclassMainActivityextendsAppCompatActivity{
privatefinal String TAG = MainActivity.class.getSimpleName();
private MapView mMapView;
private Button mRasterFunctionButton;
@OverrideprotectedvoidonCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// authentication with an API key or named user is required to access basemaps and other// location services ArcGISRuntimeEnvironment.setApiKey(BuildConfig.API_KEY);
// inflate views from layout mMapView = findViewById(R.id.mapView);
mRasterFunctionButton = findViewById(R.id.rasterButton);
mRasterFunctionButton.setEnabled(false);
// create a map with the BasemapType topographic ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_DARK_GRAY);
final ImageServiceRaster imageServiceRaster = new ImageServiceRaster(getString(R.string.image_service_raster_url));
final RasterLayer imageRasterLayer = new RasterLayer(imageServiceRaster);
map.getOperationalLayers().add(imageRasterLayer);
// zoom to the extent of the raster service imageRasterLayer.addDoneLoadingListener(() -> {
if (imageRasterLayer.getLoadStatus() == LoadStatus.LOADED) {
// get the center point Point centerPnt = imageServiceRaster.getServiceInfo().getFullExtent().getCenter();
mMapView.setViewpointCenterAsync(centerPnt, 55000000);
mRasterFunctionButton.setEnabled(true);
} else {
String error = "Error loading image raster layer: " + imageRasterLayer.getLoadError();
Log.e(TAG, error);
Toast.makeText(this, error, Toast.LENGTH_LONG).show();
}
});
// update the raster with simplified hillshade mRasterFunctionButton.setOnClickListener(v -> applyRasterFunction(imageServiceRaster));
// set the map to be displayed in this view mMapView.setMap(map);
}
privatevoidapplyRasterFunction(Raster raster){
// create raster function from json string RasterFunction rasterFuntionFromJson = RasterFunction.fromJson(getString(R.string.hillshade_simplified));
// get parameter name value pairs used by hillside RasterFunctionArguments rasterFunctionArguments = rasterFuntionFromJson.getArguments();
// get a list of raster names associated with the raster function List<String> rasterNames = rasterFunctionArguments.getRasterNames();
rasterFunctionArguments.setRaster(rasterNames.get(0), raster);
// create raster as raster layer raster = new Raster(rasterFuntionFromJson);
RasterLayer hillshadeLayer = new RasterLayer(raster);
mMapView.getMap().getOperationalLayers().add(hillshadeLayer);
}
@OverrideprotectedvoidonPause(){
super.onPause();
mMapView.pause();
}
@OverrideprotectedvoidonResume(){
super.onResume();
mMapView.resume();
}
@OverrideprotectedvoidonDestroy(){
super.onDestroy();
mMapView.dispose();
}
}