topic Create a point where line direction change exceeds specified angle in Geoprocessing Questions

Create a point where line direction change exceeds specified angle

MichaelWallis — Wed, 02 Jan 2013 10:53:09 GMT

Hi All,

I have a problem i'm trying to solve and was hoping the combined wisdom of the many would prevent me banging my head in frustration!

I have a line shapfile that contains 242 lines.
The lines represent streams & rivers.

What i'm looking to do is find all the points along the river/streams where the angle changes by a set value. I see there is a 'set representation control point by angle' tool. However i'm not overly familiar with the cartography tools and am just looking to create a point shapefile at each 'bend' in the river that exceeds a certain angle.

If possible i'd also like to know add a field that contains the actual angle change. But its not essential.

Hopefully that makes sense!

Cheers

Mike

Re: Create a point where line direction change exceeds specified angle

BruceHarold — Thu, 03 Jan 2013 14:45:46 GMT

Hi Mike

You can't work with shapefiles and the cartographic representation tools.

In the attached Python script is code that calculates the azimuth change at vertices along any line, you may be able to extract what you need from the approach.

Regards

Re: Create a point where line direction change exceeds specified angle

FerdinandRatum — Fri, 08 Feb 2013 00:10:44 GMT

Hello!,

It seems we have a similar problem with Mike though we're dealing w/ a
represented RoadCasement_L (line feature class).

We are creating fillet in every corner of the road to make it look better
in a large scale map and we're trying to detect corners that are missed
by the editor (no fillet). We figured the Set Representation Control
Point By Angle would detect angles that are equal or less than 120
degrees so that we will find the missed corners.

The tool worked without errors. We were able to distinguish the control
points (rotated vertex) over the normal vertex (square). The problem is
that we would like to export the control points to a point feature class
so we can correct and audit the errors one by one.

Is there a way to do this? Ideas are much appreciated.

Ferdinand Ratum
Engineer II, Mapping and Geodesy Department
National Mapping and Resource Information Authority
Philippines