topic Re: Corner point coordinates of polygon in ArcObjects SDK Questions

Corner point coordinates of polygon

AysberqTundra — Tue, 17 May 2011 10:08:42 GMT

I have a layer, which consisting of several square polygons. I want to create an ArcEngine application, which displays corner points coordinates of selected polygon. Can anyone help me?

Re: Corner point coordinates of polygon

UjjwalNigam — Tue, 17 May 2011 10:27:15 GMT

Hi,
Are you stuck with the selection part or the corner point part of the problem?

In case of the corner points, get the envelope of the selected feature.
Once you have the envelope, you can directly get the Lower Left & Upper Right co-ordinates.

Cheers!

Re: Corner point coordinates of polygon

AysberqTundra — Tue, 17 May 2011 11:59:55 GMT

Thanks for your reply. I will try this.

Re: Corner point coordinates of polygon

AysberqTundra — Tue, 17 May 2011 12:43:03 GMT

Thanks you, Nigam. It really was a good idea.
I tried this and find coordinates. Is there any way to display these coordinates over the points?

Re: Corner point coordinates of polygon

UjjwalNigam — Fri, 20 May 2011 09:05:42 GMT

When you say "display", do you mean like labels?
Do you just want to show them as text just above the points, or is it okay with you to highlight the corner points by some overlapping, different colored points?

Re: Corner point coordinates of polygon

RuchiraWelikala — Fri, 20 May 2011 13:17:33 GMT

The envelope method only works if the selected polygons are perfectly square and have its sides parallel to the x and y axes right?

Re: Corner point coordinates of polygon

UjjwalNigam — Mon, 23 May 2011 06:45:22 GMT

The envelope method only works if the selected polygons are perfectly square and have its sides parallel to the x and y axes right?

The envelope method works irrespective of the shape of your polygons...

Re: Corner point coordinates of polygon

NeilClemmons — Mon, 23 May 2011 12:57:36 GMT

The envelope method works irrespective of the shape of your polygons...

This is not true. The OP wants the corner coordinates of square/rectangular polygons. Unless those polygons are exactly oriented to the x, y axes using the Envelope method will not return the corner vertex coordinates of that polygon. It will return the coordinates of the envelope that encompasses the polygon. See the examples in the developer help topic for IGeometry.Envelope. To get the coordinates of the vertices that make up the polygon, use the IPointCollection interface.

Re: Corner point coordinates of polygon

AysberqTundra — Tue, 24 May 2011 06:53:24 GMT

Nigam, I find coordinates. And now I want that, when I select any polygon, it's corner coordinates shown (as label or ...) over the corner points, and when I select another polygon cleared previous labels and shown next labels. (I can't speak in english well, so sorry for my grammatical mistakes).