Perform spatial operations

View inJavaKotlin
View on GitHub
Sample viewer app

Find the union, intersection, or difference of two geometries.

Image of perform spatial operations

Use case

The different spatial operations (union, difference, symmetric difference, and intersection) can be used for a variety of spatial analyses. For example, government authorities may use the intersect operation to determine whether a proposed road cuts through a restricted piece of land such as a nature reserve or a private property.

When these operations are chained together, they become even more powerful. An analysis of food deserts within an urban area might begin by union-ing service areas of grocery stores, farmer's markets, and food co-ops. Taking the difference between this single geometry of all services areas and that of a polygon delineating a neighborhood would reveal the areas within that neighborhood where access to healthy, whole foods may not exist.

How to use the sample

Select a spatial operation from the overflow menu. When an operation is selected, the resulting geometry is shown in red.

How it works

  1. Create two GraphicsOverlays, one to show polygons and another to show the relationships between them.
  2. Define a PointCollection of each Geometry.
  3. Add the overlapping polygons to a graphics overlay.
  4. Perform spatial relationships between the polygons by using the appropriate operation:

    • GeometryEngine.union(geometry1, geometry2) - This method returns the two geometries united together as one geometry.
    • GeometryEngine.difference(geometry1, geometry2) - This method returns any part of Geometry2 that does not intersect Geometry1.
    • GeometryEngine.symmetricDifference(geometry1, geometry2) - This method returns any part of Geometry1 or Geometry2 which do not intersect.
    • GeometryEngine.intersection(geometry1, geometry2) - This method returns the intersection of Geometry1 and Geometry2.
  5. Add the resultant geometry to a new Graphic and display it by adding it to the second GraphicsOverlay.

Relevant API

  • Geometry
  • GeometryEngine
  • GeometryEngine.difference
  • GeometryEngine.intersection
  • GeometryEngine.symmetricDifference
  • GeometryEngine.union
  • Graphic
  • GraphicsOverlay

Tags

analysis, combine, difference, geometry, intersection, merge, polygon, union

Sample Code

MainActivity.kt
                                                                                                                                                                                                                                
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
/*
 * Copyright 2020 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.performspatialoperations

import android.graphics.Color
import android.os.Bundle
import android.view.Menu
import android.view.MenuItem
import androidx.appcompat.app.AppCompatActivity
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment
import com.esri.arcgisruntime.geometry.Geometry
import com.esri.arcgisruntime.geometry.GeometryEngine
import com.esri.arcgisruntime.geometry.Part
import com.esri.arcgisruntime.geometry.PartCollection
import com.esri.arcgisruntime.geometry.Point
import com.esri.arcgisruntime.geometry.PointCollection
import com.esri.arcgisruntime.geometry.Polygon
import com.esri.arcgisruntime.geometry.SpatialReferences
import com.esri.arcgisruntime.mapping.ArcGISMap
import com.esri.arcgisruntime.mapping.BasemapStyle
import com.esri.arcgisruntime.mapping.view.Graphic
import com.esri.arcgisruntime.mapping.view.GraphicsOverlay
import com.esri.arcgisruntime.mapping.view.MapView
import com.esri.arcgisruntime.sample.performspatialoperations.databinding.ActivityMainBinding
import com.esri.arcgisruntime.symbology.SimpleFillSymbol
import com.esri.arcgisruntime.symbology.SimpleLineSymbol

class MainActivity : AppCompatActivity() {

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

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

  private val inputGeometryGraphicsOverlay: GraphicsOverlay by lazy { GraphicsOverlay() }
  private val resultGeometryGraphicsOverlay: GraphicsOverlay by lazy { GraphicsOverlay() }

  // simple black line symbol for outlines
  private val lineSymbol = SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, Color.BLACK, 1f)
  private val resultFillSymbol = SimpleFillSymbol(
    SimpleFillSymbol.Style.SOLID, Color.RED, lineSymbol
  )
  private lateinit var inputPolygon1: Polygon
  private lateinit var inputPolygon2: Polygon

  // the spatial operation switching menu items.
  private var noOperationMenuItem: MenuItem? = null
  private var intersectionMenuItem: MenuItem? = null
  private var unionMenuItem: MenuItem? = null
  private var differenceMenuItem: MenuItem? = null
  private var symmetricDifferenceMenuItem: MenuItem? = null

  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)

    mapView.apply {
      // create an ArcGISMap with a light gray basemap
      map = ArcGISMap(BasemapStyle.ARCGIS_LIGHT_GRAY)

      // create graphics overlays to show the inputs and results of the spatial operation
      graphicsOverlays.add(inputGeometryGraphicsOverlay)
      graphicsOverlays.add(resultGeometryGraphicsOverlay)

    }

    // create input polygons and add graphics to display these polygons in an overlay
    createPolygons()

    // center the map view on the input geometries
    val envelope = GeometryEngine.union(inputPolygon1, inputPolygon2).extent
    mapView.setViewpointGeometryAsync(envelope, 20.0)
  }

  private fun showGeometry(resultGeometry: Geometry) {
    // add a graphic from the result geometry, showing result in red (0xFFE91F1F)
    val graphic = Graphic(resultGeometry, resultFillSymbol).also {
      // select the result to highlight it
      it.isSelected = true
    }

    resultGeometryGraphicsOverlay.graphics.add(graphic)
  }

  private fun createPolygons() {
    // create input polygon 1
    inputPolygon1 = Polygon(PointCollection(SpatialReferences.getWebMercator()).apply {
      add(Point(-13160.0, 6710100.0))
      add(Point(-13300.0, 6710500.0))
      add(Point(-13760.0, 6710730.0))
      add(Point(-14660.0, 6710000.0))
      add(Point(-13960.0, 6709400.0))

    })

    // create and add a blue graphic to show input polygon 1
    val blueFill = SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.BLUE, lineSymbol)
    inputGeometryGraphicsOverlay.graphics.add(Graphic(inputPolygon1, blueFill))

    // outer ring
    val outerRing = Part(PointCollection(SpatialReferences.getWebMercator()).apply {
      add(Point(-13060.0, 6711030.0))
      add(Point(-12160.0, 6710730.0))
      add(Point(-13160.0, 6709700.0))
      add(Point(-14560.0, 6710730.0))
      add(Point(-13060.0, 6711030.0))
    })

    // inner ring
    val innerRing = Part(PointCollection(SpatialReferences.getWebMercator()).apply {
      add(Point(-13060.0, 6710910.0))
      add(Point(-12450.0, 6710660.0))
      add(Point(-13160.0, 6709900.0))
      add(Point(-14160.0, 6710630.0))
      add(Point(-13060.0, 6710910.0))
    })

    // add both parts (rings) to a part collection and create a geometry from it
    PartCollection(outerRing).run {
      add(innerRing)
      inputPolygon2 = Polygon(this)
    }

    // create and add a green graphic to show input polygon 2
    val greenFill = SimpleFillSymbol(SimpleFillSymbol.Style.SOLID, Color.GREEN, lineSymbol)
    inputGeometryGraphicsOverlay.graphics.add(Graphic(inputPolygon2, greenFill))

  }

  override fun onCreateOptionsMenu(menu: Menu?): Boolean {
    // inflate the menu; this adds items to the action bar if it is present.
    menuInflater.inflate(R.menu.menu_main, menu)

    // Get the menu items that perform spatial operations.
    noOperationMenuItem = menu?.getItem(0)
    intersectionMenuItem = menu?.getItem(1)
    unionMenuItem = menu?.getItem(2)
    differenceMenuItem = menu?.getItem(3)
    symmetricDifferenceMenuItem = menu?.getItem(4)

    // set the 'no-op' menu item checked by default
    noOperationMenuItem?.isChecked = true

    return true
  }

  override fun onOptionsItemSelected(item: MenuItem): Boolean {
    // handle menu item selection
    val itemId = item.itemId

    // clear previous operation result
    resultGeometryGraphicsOverlay.graphics.clear()

    // perform spatial operations and add results as graphics, depending on the option selected
    when (itemId) {
      R.id.action_no_operation -> {
        // no spatial operation - graphics have been cleared previously
        noOperationMenuItem?.isChecked = true
        return true
      }
      R.id.action_intersection -> {
        intersectionMenuItem?.isChecked = true
        showGeometry(GeometryEngine.intersection(inputPolygon1, inputPolygon2))
        return true
      }
      R.id.action_union -> {
        unionMenuItem?.isChecked = true
        showGeometry(GeometryEngine.union(inputPolygon1, inputPolygon2))
        return true
      }
      R.id.action_difference -> {
        differenceMenuItem?.isChecked = true
        // note that the difference method gives different results depending on the order of input geometries
        showGeometry(GeometryEngine.difference(inputPolygon1, inputPolygon2))
        return true
      }
      R.id.action_symmetric_difference -> {
        symmetricDifferenceMenuItem?.isChecked = true
        showGeometry(GeometryEngine.symmetricDifference(inputPolygon1, inputPolygon2))
        return true
      }
      else -> {
        return super.onOptionsItemSelected(item)
      }
    }
  }

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

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

  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.