Contours Generation - Discard Closed Contour Lines Shorter than IGNORED

hover

Whatever I try in terms of length, this option seems not to be respected (anymore). If I remember correctly, it used to work in earlier versionen, maybe v16 or 15.

Global Mapper v17.1.0 (64 bit).

hover

Earlier post found claiming exactly the same behavior.

bmg_bob

Hello,

First, I recommend that you try the latest version of Global Mapper 17.  I ran a quick contouring test, and the "Discard Closed Contour Lines Shorter than" options seems to be working fine.

If you are still having a problem with the latest release of Global Mapper, please provide a detailed description of your workflow so we can try to reproduce it here.

Cheers,

Bob

hover

Hi Bob

I updated to the most recent version but still have the same problem.
See the attached screenshots
- contour generation options
- contours, many very, very small and closed, down to 1 meter length

Am I missing something?

bmg_bob

Hello,

I still can't reproduce this problem.  What setting did you use on the Simplification tab?  Can you attach a zip archive containing your workspace and data?

Cheers,

Bob

hover

Simplification is set to 2 (1.99).

hover

Workspace is pretty small but data is huge. 

hover

I zipped everything but the result is almost 1gb of data ...
Does it make sense to try to upload it?

hover

Upload doesn't seem to work for this file size.

hover

Important note: There actually is a big difference in number of generated contours, if using this option. However, it seems that not all (closed) contour lines below that limit are suppressed...

Could it be that they look closed but actually aren't? How can I easily double-check?

hover

Or, as a workaround, is there a way to specifically select very short contour lines in order to delete them after generation?

bmg_bob

hover said:

I zipped everything but the result is almost 1gb of data ...
Does it make sense to try to upload it?

Probably not (as you discovered).  Can you export a smaller subset of your data that illustrates the problem?  

hover said:

Could it be that they look closed but actually aren't? How can I easily double-check?

If you look at the contour with the Feature Information tool, closed contours will have an attribute CLOSED_CONTOUR with a value of YES.

Or, as a workaround, is there a way to specifically select very short contour lines in order to delete them after generation?

Select all of the features in your contour layer, right-click, and choose Attribute/Style Functions | Add/Update the Measure Attributes of Selected Features.  Then you can use the Search by Attribute function to find short contours.

Cheers,

Bob

hover

I will look into this and get back. Thanks a lot already.

hover

Hi Bob
the contour I'm investigating looks "very closed" but the feature information has no CLOSED_CONTOUR attribute at all...
Am I wrong?

hennie

Try the Search function - you will most probable see attributes there that is not normally shown in the feature info window.

hover

Yet another contour supposed to be closed. Vertex 1 and vertex 9 have to the position... 

hover

Now I'm looking at the "Search by Attribute function", I sort all the generated contours by clicking on LENGTH. Everything looks fine except the two contours marked yellow. 

What's going on?

hover

hover said:

Now I'm looking at the "Search by Attribute function", I sort all the generated contours by clicking on LENGTH. Everything looks fine except the two contours marked yellow. 

What's going on?

Alphabetic rather than numeric sort order?

bmg_bob

hover said:

hover said:

Now I'm looking at the "Search by Attribute function", I sort all the generated contours by clicking on LENGTH. Everything looks fine except the two contours marked yellow. 

What's going on?

Alphabetic rather than numeric sort order?

Yes.  In the Search Criteria, under Compare Value, change the "as" value to "Number".  It is not obvious, but that field controls whether sorting is done as alphabetic or numeric.

hover said:

Yet another contour supposed to be closed. Vertex 1 and vertex 9 have to the position... 

This and the previous example both appear to be closed.  Do you see other contours that do have the CLOSED_CONTOUR attribute?  Have you determined whether or not you can export a subset of your data that can be used to reproduce this problem?

Cheers,

Bob

iaerobotics

I have this same issue and can export small area for reproducing if you can work on what might be going on? Also seems to be an issue with the search/sort of LENGTH for contour lines between ft, miles, etc.

bmg_bob

Hello,

I suggest that you contact Blue Marble Support directly via email (geohelp@bluemarblegeo.com) to address this issue. Please provide a detailed description of your workflow, including screen captures of the options screen, and the sample data that can be used to reproduce the problem. Thank you.

Cheers,
Bob

iaerobotics

Ok. Thanks for the suggestion. Does this point to issues not being tracked and worked through this forum any longer? That's understandable but just not sure if that's an official thing or nor?

Thanks.