Why does not equal computing line in `OpenLayers` with `ArcGIS` when i use measure control?

Question

My map projection is: "EPSG:900913" ,Display projection is "EPSG:4326" and units is "m", however does not equal the length is calculated in OpenLayers with ArcGIS, in fact Openlayers show the length more than the actual length when i use measure control.

For example:

the calculation length in ArcGIS is:26,072.443575

and in OpenLayers is: 3.0757.

How to resolve this problem?

Please edit the question to provide the coordinates of the line. — Vince, Sep 29 '15 at 16:43
If you're just clicking on the screen, graphical representation issues around pixel size and "twips" could more than explain the difference. — Vince, Sep 30 '15 at 05:15
have you already set the option geodesic: true to your measure control? — Thomas B, Oct 06 '15 at 10:24
@ThomasB Yes. but i use DynamicMeasure too, that dont have geodesic property. — Samane, Oct 06 '15 at 10:32
do you mean https://github.com/jorix/OL-DynamicMeasure ? perhaps you can post a bit of your code... — Thomas B, Oct 06 '15 at 12:00
@ThomasB Yes, I mean the same thing, also i have this problem in insertDirectionLength,... — Samane, Oct 06 '15 at 12:18

score 1 · Accepted Answer · answered Oct 06 '15 at 13:01

1

As you are using DynamicMeasure( github.com/jorix/OL-DynamicMeasure ) you can also use geodesic:true to get better results:

var measureControls = {
        line: new OpenLayers.Control.DynamicMeasure(OpenLayers.Handler.Path)

    };

measureControls.line.geodesic=true;

measureControls.line.activate();

I just forked the repository and added an option to switch geodesic:true on interactively:

http://rawgit.com/neogis-de/OL-DynamicMeasure/geodesic/examples/measure-dynamic.html

answered Oct 06 '15 at 13:01

Thomas B

8,807
1
21
62

i have same problem in insertDirectionLength, How to resolve this problem??? – Samane Oct 07 '15 at 09:38
you better post this as a seperate question – Thomas B Oct 07 '15 at 09:42
I asked this question: http://gis.stackexchange.com/questions/167673/why-does-not-equal-length-of-line-in-direction-length-with-length-of-line-in-mea?noredirect=1#comment249639_167673, please reply it! – Samane Oct 27 '15 at 05:57

Why does not equal computing line in `OpenLayers` with `ArcGIS` when i use measure control?

1 Answers1