Raster rendering rule

View inJavaKotlin
View on GitHub
Sample viewer app

Display a raster on a map and apply different rendering rules to that raster.

Image of raster rendering rule

Use case

Raster images whose individual pixels represent elevation values can be rendered in a number of different ways, including representation of slope, aspect, hillshade, and shaded relief. Applying these different rendering rules to the same raster allows for a powerful visual analysis of the data. For example, a geologist could interrogate the raster image to map subtle geological features on a landscape, which may become apparent only through comparing the raster when rendered using several different rules.

How to use the sample

Run the sample and use the drop-down menu at the top to select a rendering rule.

How it works

  1. Create an ImageServiceRaster using a URL to an online image service.
  2. After loading the raster, use imageServiceRaster.serviceInfo.renderingRuleInfos to get a list of RenderingRuleInfo supported by the service.
  3. Choose a rendering rule info to apply and use it to create a RenderingRule.
  4. Create a new ImageServiceRaster using the same URL.
  5. Apply the rendering rule to the new raster using imageServiceRaster.renderingRule(renderingRuleInfo).
  6. Create a RasterLayer from the raster for display.

Relevant API

  • ImageServiceRaster
  • RasterLayer
  • RenderingRule

About the data

This raster image service contains 9 LAS files covering Charlotte, North Carolina's downtown area. The lidar data was collected in 2007. Four Raster Rules are available for selection: None, RFTAspectColor, RFTHillshade, and RFTShadedReliefElevationColorRamp.

Additional information

Image service rasters of any type can have rendering rules applied to them; they need not necessarily be elevation rasters. See the list of raster function objects and syntax for rendering rules in the ArcGIS REST API documentation.

Tags

raster, rendering rules, visualization

Sample Code

MainActivity.kt
Use dark colors for code blocks
                                                                                                                                                  
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
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/* 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.
 *
 */

package com.esri.arcgisruntime.sample.rasterrenderingrule

import android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.AdapterView
import android.widget.ArrayAdapter
import android.widget.Spinner
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment
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.RenderingRule
import com.esri.arcgisruntime.sample.rasterrenderingrule.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

  private val TAG = this::class.java.simpleName

  private val activityMainBinding by lazy {
    ActivityMainBinding.inflate(layoutInflater)
  }

  private val mapView: MapView by lazy {
    activityMainBinding.mapView
  }

  private val spinner: Spinner by lazy {
    activityMainBinding.spinner
  }

  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(activityMainBinding.root)

    // authentication with an API key or named user is required to access basemaps and other
    // location services
    ArcGISRuntimeEnvironment.setApiKey(BuildConfig.API_KEY)

    // create image service raster as raster layer and add to map
    val imageServiceRaster = ImageServiceRaster(getString(R.string.image_service_url))
    val imageRasterLayer = RasterLayer(imageServiceRaster)

    // create a Streets BaseMap
    val map = ArcGISMap(BasemapStyle.ARCGIS_STREETS).apply {
      operationalLayers.add(imageRasterLayer)
    }

    // set the map to be displayed in this view
    mapView.map = map

    val renderRulesList = mutableListOf<String>()
    val spinnerAdapter = ArrayAdapter(this, android.R.layout.simple_list_item_1, renderRulesList)
    spinner.adapter = spinnerAdapter
    // zoom to the extent of the raster service
    imageRasterLayer.addDoneLoadingListener {
      if (imageRasterLayer.loadStatus == LoadStatus.LOADED) {
        // zoom to extent of raster
        mapView.setViewpointGeometryAsync(imageServiceRaster.serviceInfo.fullExtent)
        // get the predefined rendering rules and add to spinner
        val renderingRuleInfos = imageServiceRaster.serviceInfo.renderingRuleInfos
        for (renderRuleInfo in renderingRuleInfos) {
          val renderingRuleName = renderRuleInfo.name
          renderRulesList.add(renderingRuleName)
          // update array adapter with list update
          spinnerAdapter.notifyDataSetChanged()
        }
      } else {
        val error = "Error loading raster: " + imageRasterLayer.loadError.message
        Log.e(TAG, error)
        Toast.makeText(this, error, Toast.LENGTH_LONG).show()
      }
    }

    // listen to the spinner
    spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
      override fun onNothingSelected(parent: AdapterView<*>?) {  }

      override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) =
        applyRenderingRule(imageServiceRaster, position)
    }
  }

  /**
   * Apply a rendering rule on a Raster and add it to the map
   *
   * @param imageServiceRaster image service raster to apply rendering on
   * @param index spinner selected position representing the rule to apply
   */
  fun applyRenderingRule(imageServiceRaster: ImageServiceRaster, index: Int) {

    // get the rendering rule info at the selected index
    val renderRuleInfo = imageServiceRaster.serviceInfo.renderingRuleInfos[index]
    // create a rendering rule object using the rendering rule info
    val renderingRule = RenderingRule(renderRuleInfo)
    // create a new image service raster
    val appliedImageServiceRaster = ImageServiceRaster(getString(R.string.image_service_url))
    // apply the rendering rule
    appliedImageServiceRaster.renderingRule = renderingRule
    // create a raster layer using the image service raster
    val rasterLayer = RasterLayer(appliedImageServiceRaster)

    mapView.map.operationalLayers.let {
      // clear all rasters
      it.clear()
      // add the raster layer to the map
      it.add(rasterLayer)
    }
  }

  override fun onPause() {
    mapView.pause()
    super.onPause()
  }

  override fun onResume() {
    super.onResume()
    mapView.resume()
  }

  override fun onDestroy() {
    mapView.dispose()
    super.onDestroy()
  }
}

Your browser is no longer supported. Please upgrade your browser for the best experience. See our browser deprecation post for more details.