TransDEM Forum

In working with polylines to trace my track route, I've got 2 questions...

1) I like to keep my route in segments. Is there a way to tell the length of my current segment (distance from last point) as I'm tracing instead of the entire length of the whole polyline? I believe that's what shows in the status bar.

2) I made one long polyline as the track I'm working on is long and straight. I want to break the line into segments, especially where I know a junction will be. I right click and choose "Add Point", but if I'm not spot on with my click, the new point will pull the polyline off. What was once a straight polyline is now jagged. Other than zooming way in, is there a way to keep the point I'm adding directly on the existing polyline?

Thank you for your time.

Andrew

SharkNose wrote:Is there a way to tell the length of my current segment (distance from last point) as I'm tracing instead of the entire length of the whole polyline? I believe that's what shows in the status bar.

There is a basic tool for this: "Measure distance" (Route menu and toolbar). It works like a volatile polyline. If set to imperial (General settings), it shows length in miles and feet.

Another option is the coordinate grid. Except for geographic (lat/lon), all coordinate systems are in metres. The grid is often quite helpful to estimate the size of a segment/module without explicit measurement. So, if one grid line is labelled 360000 and the next one 370000, the difference in 10000 metres or a good 6 mi.

Other than zooming way in, is there a way to keep the point I'm adding directly on the existing polyline?

I'm afraid not. The "Simple Route Editor" was never intended to be a fully-fledged vector editing tool. You would need an external tool for more advanced editing functions. JOSM, for instance, the offline editor for Open Street Map, does have such features. You can exchange data between TransDEM and JOSM in GPX format. See here for more JOSM usage: http://forum.transdem.de/viewtopic.php?f=6&t=158

Thanks for the reply, geophil. I'll check JOSM out! As far as polyline segment lengths go, I'm sure the more I practice, the better I'll get at trying to make them somewhat equal in length.