Points to Line

ShiminCai

Hi,

Does anybody get any idea of converting points to line please? I'm thinking to construct a line json from point jsons and then create a line geometry with the method initWithJSON of AGSPolyline... If this is correct, what would be the best way of constructing the line json from the points jsons?

Thanks in Advance.

Shimin

ShiminCai

Hi All,

The line json constructed from points worked. It only took 3 seconds to draw lines for 22000 points.

Here is the function in case anybody else needs it:

@IBAction func convertTrackPointToLine(sender: UIBarButtonItem)

    {

        if self.trackPointLineOn

        {

            self.trackPointLineOn = false

            self.trackPointToLineButton.tintColor = nil

            self.mapView.removeMapLayerWithName(TRACKPOINTLINELAYERNAME)

            self.trackPointLineGraphicLayer = nil

        }

        else

        {

            let query = AGSQuery()

            query.outFields = ["TrackID", "TrackPointNo", "Description", "Contractor", "Operation", "OperationDetail"]

            query.orderByFields = ["TrackID ASC", "TrackPointNo ASC"]

            query.geometry = self.mapView.visibleArea()

            query.spatialRelationship = AGSSpatialRelationship.Intersects

            query.returnGeometry = true

           

            let trackPointsFeatureTable = self.trackPointsLayer.table

            trackPointsFeatureTable.queryResultsWithParameters(query)

            {

                (features: [AnyObject]!, error: NSError!) -> Void in

                if error != nil

                {

                    logAppStatus("Error querying the TrackPoints layer: " + "\(error)", newLine: "\n")

                    FCNSWUtils.showAlertWithTitle("Query Error", andMessage: "Error querying the TrackPoints layer: " + "\(error).")

                }

                else

                {

                    let featureSet = AGSFeatureSet(features: features)

                   

                    let lineJsonPart1 = "{\"paths\":[["

                    var lineJsonPart2 = ""

                    let lineJsonPart3 = "]],\"spatialReference\":{\"wkid\":3308}}"

                   

                    var count = 0

                    for feature: AGSGDBFeature in featureSet.features as! [AGSGDBFeature]

                    {

                        let point : AGSPoint = feature.geometry as! AGSPoint

                        let pointJsonValue = point.encodeToJSON() as NSDictionary

                        let x: Double = pointJsonValue.valueForKey("x") as! Double

                        let y: Double = pointJsonValue.valueForKey("y") as! Double

                        let pointXY = "[\(x),\(y)]"

                        if count == 0

                        {

                            lineJsonPart2 += pointXY

                        }

                        else

                        {

                            lineJsonPart2 += "," + pointXY

                        }

                       

                        count++

                    }

                   

                    let lineJson = lineJsonPart1 + lineJsonPart2 + lineJsonPart3

                    let lineJsonValue = (lineJson as NSString).ags_JSONValue() as! NSDictionary

                    let lineGeometry = AGSPolyline(JSON: lineJsonValue as [NSObject : AnyObject], spatialReference: self.mapView.spatialReference)

                   

                    self.trackPointLineGraphicLayer = AGSGraphicsLayer.graphicsLayer() as! AGSGraphicsLayer

                    self.mapView.addMapLayer(self.trackPointLineGraphicLayer, withName: TRACKPOINTLINELAYERNAME)

                   

                    let blueSimpleLineSymbol = AGSSimpleLineSymbol.init(color: UIColor.blueColor())

                    let blueSimpleLineGraphic = AGSGraphic.graphicWithGeometry(lineGeometry, symbol: blueSimpleLineSymbol, attributes: nil) as! AGSGraphic

                    self.trackPointLineGraphicLayer.addGraphic(blueSimpleLineGraphic)

                   

                    self.trackPointLineOn = true

                    self.trackPointToLineButton.tintColor = UIColor.cyanColor()

                }

            }

        }

    }

Cheers,

Shimin