topic Re: Features within a geometry in Qt Maps SDK Questions

Features within a geometry

TaimoorKhan — Wed, 25 Jul 2018 14:44:15 GMT

Hi, I'm making a QML application where I want to see if the features of one feature layer (which are points) are within the bounds of another feature layer which is of geometryType esriGeometryPolygon (https://livefeeds.arcgis.com/arcgis/rest/services/LiveFeeds/Wildfire_Activity/MapServer/2 this is the actual layer if it helps). Currently I'm getting data on wildfires by doing a queryFeaturesWithFieldOptions on the Active Fire Report layer to gain info on wildfires in my current extent, but I want to see the points of the other feature which are within the polygon of the perimeter. Within my QueryParameters I see options for spatialRelationship, outSpatialReference, and geometry so I definitely think what I'm trying to do is possible, but from my testing I haven't gotten the results I want yet. Any help would be appreciated, and I can answer any questions if needed.

Re: Features within a geometry

LucasDanzinger — Fri, 10 Dec 2021 22:17:15 GMT

Sounds like you're on the right track. Here is an example of using a polygon to find points that are within it. Just click on a state and you can see what cities are within that state:

import QtQuick 2.6
import QtQuick.Controls 1.4
import Esri.ArcGISRuntime 100.3

ApplicationWindow {
    id: appWindow
    width: 800
    height: 600
    title: "SpatialQuery"

    // add a mapView component
    MapView {
        anchors.fill: parent
        // set focus to enable keyboard navigation
        focus: true

        // add a map to the mapview
        Map {
            // add the BasemapTopographic basemap to the map
            BasemapTopographic {}

            FeatureLayer {
                id: statesLayer
                ServiceFeatureTable {
                    id: statesTable
                    url: "http://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer/2"
                }
            }

            FeatureLayer {
                id: citiesLayer
                ServiceFeatureTable {
                    id: citiesTable
                    url: "http://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer/0"

                    onQueryFeaturesStatusChanged: {
                        if (queryFeaturesStatus !== Enums.TaskStatusCompleted)
                            return;

                        var resultIter = queryFeaturesResult.iterator;
                        while (resultIter.hasNext) {
                            var feat = resultIter.next();
                            citiesLayer.selectFeature(feat)
                            console.log("City:", feat.attributes.attributeValue("areaname"));
                        }
                    }
                }
            }
        }

        onMouseClicked: {
            // clear selection and identify layers
            statesLayer.clearSelection();
            citiesLayer.clearSelection();
            identifyLayerWithMaxResults(statesLayer, mouse.x, mouse.y, 10, false, 1)
        }

        onIdentifyLayerStatusChanged: {
            if (identifyLayerStatus !== Enums.TaskStatusCompleted)
                return;

            // select the state layer that was identified
            var result = identifyLayerResult.geoElements[0];
            statesLayer.selectFeature(result);

            // find all the cities in that polygon

            // create the params
            var queryParams = ArcGISRuntimeEnvironment.createObject("QueryParameters");
            queryParams.geometry = result.geometry;
            queryParams.spatialRelationship = Enums.SpatialRelationshipIntersects;

            // query the table
            citiesTable.queryFeatures(queryParams)
        }
    }
}
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Re: Features within a geometry

TaimoorKhan — Wed, 25 Jul 2018 17:46:04 GMT

Thank you for this example! This gives me a good place to start. Rather than clicking the state and then seeing the cities, the behavior I'm looking for is that the user clicks a city and then the state is logged, but this is a good example for me to work from and I'm sure I can tweak it so that I can get what I want. I'll post later if I have further questions, but I greatly appreciate your help!