topic Re: draw line programmatically in ArcGIS Viewer for Flex Questions

draw line programmatically

LefterisKoumis — Tue, 04 Jun 2013 21:54:47 GMT

Similar to the polylines that google overlays on their map, I am looking for a similar functionality to draw a line on a map based on predefined sets of coordinates. The app for the hurricanes provides this functionality at http://www.arcgis.com/home/webmap/viewer.html?webmap=2f5a28f82f4d41ec8dbe6cf96375a970.

Any ideas?

Re: draw line programmatically

RhettZufelt — Wed, 05 Jun 2013 00:01:11 GMT

the hurricane map looks like it is consuming a feed with the track data so the line is pre-rendered.

Are you looking for a way to make a service that updates itself when the points of the line change (like from an event theme) or actually having someone enter two coordinates in the flexviewer, and having it draw the line?

R_

Re: draw line programmatically

RobertScheitlin__GISP — Sat, 11 Dec 2021 08:59:25 GMT

Lefteris,

Drawing a line programatically is quite simple you just create an array of points and add them to a polylines path.

                            var pA:Array;
                             pA = [];
                            //just some loop to add all your XYs for your lines points
                            for (m=0; m<gArrObj.length; m++){
                                pA.push(new MapPoint(X,Y,new SpatialReference(102100)));
                            }
                            var pLine:Polyline = new Polyline(null,new SpatialReference(102100));
                            pLine.addPath(pA);
                            var gra:Graphic = new Graphic(pLine);
                            graphicsLayer.add(gra);

Re: draw line programmatically

LefterisKoumis — Wed, 05 Jun 2013 14:30:40 GMT

the hurricane map looks like it is consuming a feed with the track data so the line is pre-rendered.

Are you looking for a way to make a service that updates itself when the points of the line change (like from an event theme) or actually having someone enter two coordinates in the flexviewer, and having it draw the line?

R_

Thanks for the reply. The second case, to enter two coordinates in the flexviewer, and having it draw the line.

Re: draw line programmatically

RhettZufelt — Wed, 05 Jun 2013 14:50:34 GMT

In that case, it looks like Robert has put you on the right track.

R_

Re: draw line programmatically

LefterisKoumis — Sat, 11 Dec 2021 08:59:28 GMT

Lefteris,

Drawing a line programatically is quite simple you just create an array of points and add them to a polylines path.

                            var pA:Array;
                             pA = [];
                            //just some loop to add all your XYs for your lines points
                            for (m=0; m<gArrObj.length; m++){
                                pA.push(new MapPoint(X,Y,new SpatialReference(102100)));
                            }
                            var pLine:Polyline = new Polyline(null,new SpatialReference(102100));
                            pLine.addPath(pA);
                            var gra:Graphic = new Graphic(pLine);
                            graphicsLayer.add(gra);

Thank you Robert. Very similar to the google javascript code. A challenging task is to overlay a section of a line from a line layer and following its path. Other than inserting multiple points on the line I don't see any other way to be done.

Re: draw line programmatically

RobertScheitlin__GISP — Wed, 05 Jun 2013 15:06:42 GMT

Lefteris,

I am not sure if there is question in your last post or not...?

Re: draw line programmatically

LefterisKoumis — Wed, 05 Jun 2013 15:06:45 GMT

In that case, it looks like Robert has put you on the right track.

R_

Yes. Thank you.

Re: draw line programmatically

LefterisKoumis — Wed, 05 Jun 2013 15:18:30 GMT

Lefteris,

I am not sure if there is question in your last post or not...?

Sorry for confusion....I was just throwing my thoughts out about overlay over a section of a line without the need of multiple points to establish the path of the overlay over the line. For example, if you need to overlay a section of a road to show the project limits, how can you do it other than inserting multiple points along the section? I don't think there is anything out there yet...