Clip geometry

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Clip a geometry with another geometry.

Image of clip geometry

Use case

Create a new set of geometries for analysis (e.g. displaying buffer zones around abandoned coal mine shafts in an area of planned urban development) by clipping intersecting geometries.

How to use the sample

Tap the "Clip" button to clip the blue graphic with the red dashed envelopes.

How it works

  1. Use the static method GeometryEngine.clip() to generate a clipped Geometry, passing in an existing Geometry and an Envelope as parameters. The existing geometry will be clipped where it intersects an envelope.
  2. Create a new Graphic from the clipped geometry and add it to a GraphicsOverlay on the MapView.

Relevant API

  • Envelope
  • Geometry
  • GeometryEngine.clip
  • Graphic
  • GraphicsOverlay

Additional information

Note: the resulting geometry may be null if the envelope does not intersect the geometry being clipped.

Tags

analysis, clip, geometry

Sample Code

MainActivity.kt
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/* Copyright 2022 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.arcgismaps.sample.clipgeometry

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.DataBindingUtil
import com.arcgismaps.ApiKey
import com.arcgismaps.ArcGISEnvironment
import com.arcgismaps.Color
import com.arcgismaps.geometry.Envelope
import com.arcgismaps.geometry.GeometryEngine
import com.arcgismaps.geometry.Point
import com.arcgismaps.mapping.ArcGISMap
import com.arcgismaps.mapping.BasemapStyle
import com.arcgismaps.mapping.Viewpoint
import com.arcgismaps.mapping.symbology.SimpleFillSymbol
import com.arcgismaps.mapping.symbology.SimpleFillSymbolStyle
import com.arcgismaps.mapping.symbology.SimpleLineSymbol
import com.arcgismaps.mapping.symbology.SimpleLineSymbolStyle
import com.arcgismaps.mapping.view.Graphic
import com.arcgismaps.mapping.view.GraphicsOverlay
import com.esri.arcgismaps.sample.clipgeometry.databinding.ClipGeometryActivityMainBinding

class MainActivity : AppCompatActivity() {

    // graphics overlay along the Colorado state border
    private val coloradoOverlay: GraphicsOverlay by lazy { GraphicsOverlay() }

    // graphics overlay to contain the clipping envelopes
    private val envelopesOverlay: GraphicsOverlay by lazy { GraphicsOverlay() }

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

        // authentication with an API key or named user is
        // required to access basemaps and other location services
        ArcGISEnvironment.apiKey = ApiKey.create(BuildConfig.ACCESS_TOKEN)
        // set up data binding for the activity
        val activityMainBinding: ClipGeometryActivityMainBinding =
            DataBindingUtil.setContentView(this, R.layout.clip_geometry_activity_main)
        // get the MapView instance from the data binding
        val mapView = activityMainBinding.mapView
        lifecycle.addObserver(mapView)

        // create buttons to perform the clip and reset operations on the geometry
        val clipButton = activityMainBinding.clipButton
        val resetButton = activityMainBinding.resetButton

        // create and add a map with a topographic basemap style
        mapView.map = ArcGISMap(BasemapStyle.ArcGISTopographic)
        // set the viewpoint of the MapView
        mapView.setViewpoint(Viewpoint(40.0, -106.0, 10000000.0))

        // create a graphics overlay to contain the geometry to clip
        mapView.graphicsOverlays.add(coloradoOverlay)
        val (coloradoGraphic, fillSymbol) = createGraphics(coloradoOverlay)

        // create a graphics overlay to contain the clipping envelopes
        mapView.graphicsOverlays.add(envelopesOverlay)
        createEnvelope(envelopesOverlay)

        // create a graphics overlay to contain the clipped areas
        val clipAreasOverlay = GraphicsOverlay()
        mapView.graphicsOverlays.add(clipAreasOverlay)

        clipButton.setOnClickListener {
            // disable button
            clipButton.isEnabled = false
            resetButton.isEnabled = true
            // for each envelope, clip the Colorado geometry and show the result,
            // replacing the original Colorado graphic
            coloradoGraphic.isVisible = false
            for (graphic in envelopesOverlay.graphics) {
                val geometry =
                    coloradoGraphic.geometry?.let { coloradoGeometry ->
                        GeometryEngine.clipOrNull(coloradoGeometry, graphic.geometry as Envelope)
                    }
                val clippedGraphic = Graphic(geometry, fillSymbol)
                clipAreasOverlay.graphics.add(clippedGraphic)
            }
        }

        resetButton.setOnClickListener {
            // clear clipped graphic
            clipAreasOverlay.graphics.clear()

            // set the visibility of the colorado graphic to true
            coloradoGraphic.isVisible = true

            clipButton.isEnabled = true
            resetButton.isEnabled = false
        }
    }

    /**
     * Create colorado graphic.
     */
    private fun createGraphics(
        coloradoOverlay: GraphicsOverlay,
    ) : Pair<Graphic, SimpleFillSymbol>{
        // create a blue graphic of Colorado
        val colorado = Envelope(
            Point(-11362327.128340, 5012861.290274),
            Point(-12138232.018408, 4441198.773776)
        )
        val fillSymbol = SimpleFillSymbol(
            SimpleFillSymbolStyle.Solid,
            Color(R.color.transparentDarkBlue),
            SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.green, 2f)
        )
        val coloradoGraphic = Graphic(colorado, fillSymbol)
        coloradoOverlay.graphics.add(coloradoGraphic)
        return Pair(coloradoGraphic, fillSymbol)
    }

    /**
     * Create three envelopes, outside, inside and intersecting colorado graphic.
     */
    private fun createEnvelope(
        envelopesOverlay: GraphicsOverlay,
    ) {
        // create a dotted red outline symbol
        val redOutline = SimpleLineSymbol(SimpleLineSymbolStyle.Dot, Color.red, 3f)

        // create a envelope outside Colorado
        val outsideEnvelope = Envelope(
            Point(-11858344.321294, 5147942.225174),
            Point(-12201990.219681, 5297071.577304)
        )
        val outside = Graphic(outsideEnvelope, redOutline)
        envelopesOverlay.graphics.add(outside)

        // create a envelope intersecting Colorado
        val intersectingEnvelope = Envelope(
            Point(-11962086.479298, 4566553.881363),
            Point(-12260345.183558, 4332053.378376)
        )
        val intersecting = Graphic(intersectingEnvelope, redOutline)
        envelopesOverlay.graphics.add(intersecting)

        // create a envelope inside Colorado
        val containedEnvelope = Envelope(
            Point(-11655182.595204, 4741618.772994),
            Point(-11431488.567009, 4593570.068343)
        )
        val contained = Graphic(containedEnvelope, redOutline)
        envelopesOverlay.graphics.add(contained)
    }
}

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