Create buffers around points sample (#425)

Co-authored-by: Shubham Sharma <shubhamsharma@esri.com>

Author: rchintapalli

samples/create-buffers-around-points/README.md

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+# Create buffers around points
+
+Generate multiple individual buffers or a single unioned buffer around multiple points.
+
+![Image of create buffers around points](create-buffers-around-points.png)
+
+## Use case
+
+Creating buffers is a core concept in GIS proximity analysis that allows you to visualize and locate geographic features contained within a set distance of a feature. For example, consider an area where wind turbines are proposed. It has been determined that each turbine should be located at least 2 km away from residential premises due to noise pollution regulations, and a proximity analysis is therefore required. The first step would be to generate 2 km buffer polygons around all proposed turbines. As the buffer polygons may overlap for each turbine, unioning the result would produce a single graphic result with a neater visual output. If any premises are located within 2 km of a turbine, that turbine would be in breach of planning regulations.
+
+## How to use the sample
+
+Click/tap on the map to add points. Click the "Create Buffer(s)" button to draw buffer(s) around the points (the size of the buffer is determined by the value entered by the user). Check the check box if you want the result to union (combine) the buffers. Click the "Clear" button to start over. The red dashed envelope shows the area where you can expect reasonable results for planar buffer operations with the North Central Texas State Plane spatial reference.
+
+## How it works
+
+1. Use `GeometryEngine.bufferOrNull(point, radius)` to create a `Polygon` and `GeometryEngine.unionOrNull(polygons)` to union polygons. The parameter `points` are the points to buffer around, `distances` are the buffer distances for each point (in meters).
+2. Add the resulting polygons (if not unioned) or single polygon (if unioned) to the map's `GraphicsOverlay` as a `Graphic`.
+
+## Relevant API
+
+* Geometry
+* GeometryEngine.bufferOrNull
+* GeometryEngine.unionOrNull
+* SpatialReference
+
+## Additional information
+
+The properties of the underlying projection determine the accuracy of buffer polygons in a given area. Planar buffers work well when analyzing distances around features that are concentrated in a relatively small area in a projected coordinate system. Inaccurate buffers could still be created by buffering points inside the spatial reference's envelope with distances that move it outside the envelope. On the other hand, geodesic buffers consider the curved shape of the Earth's surface and provide more accurate buffer offsets for features that are more dispersed (i.e., cover multiple UTM zones, large regions, or even the whole globe). See the "Buffer" sample for an example of a geodesic buffer.
+
+For more information about using buffer analysis, see the topic [How Buffer (Analysis) works](https://pro.arcgis.com/en/pro-app/tool-reference/analysis/how-buffer-analysis-works.htm) in the *ArcGIS Pro* documentation.
+
+## Tags
+
+analysis, buffer, geometry, planar

samples/create-buffers-around-points/README.metadata.json

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+{
+    "category": "Analysis",
+    "description": "Generate multiple individual buffers or a single unioned buffer around multiple points.",
+    "formal_name": "CreateBuffersAroundPoints",
+    "ignore": false,
+    "images": [
+        "create-buffers-around-points.png"
+    ],
+    "keywords": [
+        "analysis",
+        "buffer",
+        "geometry",
+        "planar",
+        "Geometry",
+        "GeometryEngine.bufferOrNull",
+        "GeometryEngine.unionOrNull",
+        "SpatialReference"
+    ],
+    "language": "kotlin",
+    "redirect_from": "",
+    "relevant_apis": [
+        "Geometry",
+        "GeometryEngine.bufferOrNull",
+        "GeometryEngine.unionOrNull",
+        "SpatialReference"
+    ],
+    "snippets": [
+        "src/main/java/com/esri/arcgismaps/sample/createbuffersaroundpoints/components/CreateBuffersAroundPointsViewModel.kt",
+        "src/main/java/com/esri/arcgismaps/sample/createbuffersaroundpoints/MainActivity.kt",
+        "src/main/java/com/esri/arcgismaps/sample/createbuffersaroundpoints/screens/CreateBuffersAroundPointsScreen.kt"
+    ],
+    "title": "Create buffers around points"
+}

samples/create-buffers-around-points/build.gradle.kts

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+plugins {
+    alias(libs.plugins.arcgismaps.android.library)
+    alias(libs.plugins.arcgismaps.android.library.compose)
+    alias(libs.plugins.arcgismaps.kotlin.sample)
+    alias(libs.plugins.gradle.secrets)
+}
+
+secrets {
+    // this file doesn't contain secrets, it just provides defaults which can be committed into git.
+    defaultPropertiesFileName = "secrets.defaults.properties"
+}
+
+android {
+    namespace = "com.esri.arcgismaps.sample.createbuffersaroundpoints"
+    buildFeatures {
+        buildConfig = true
+    }
+}
+
+dependencies {
+    // Only module specific dependencies needed here
+}

samples/create-buffers-around-points/create-buffers-around-points.png

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application><activity
+            android:exported="true"
+            android:name=".MainActivity"
+            android:label="@string/create_buffers_around_points_app_name">
+            
+        </activity>
+    </application>
+
+</manifest>

samples/create-buffers-around-points/src/main/AndroidManifest.xml

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+/* Copyright 2025 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.createbuffersaroundpoints
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.runtime.Composable
+import com.arcgismaps.ApiKey
+import com.arcgismaps.ArcGISEnvironment
+import com.esri.arcgismaps.sample.sampleslib.theme.SampleAppTheme
+import com.esri.arcgismaps.sample.createbuffersaroundpoints.screens.CreateBuffersAroundPointsScreen
+
+class MainActivity : ComponentActivity() {
+
+    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)
+
+        setContent {
+            SampleAppTheme {
+                CreateBuffersAroundPointsApp()
+            }
+        }
+    }
+
+    @Composable
+    private fun CreateBuffersAroundPointsApp() {
+        Surface(color = MaterialTheme.colorScheme.background) {
+            CreateBuffersAroundPointsScreen(
+                sampleName = getString(R.string.create_buffers_around_points_app_name)
+            )
+        }
+    }
+}