If you want to see all of the individual points in a grid as points with
elevation labels, what you can do is load the elevation layer, then export a
XYZ file using the File->Export Raster and Elevation->Export XYZ Grid menu
command. Then, load that XYZ file back in using the File->Open Generic ASCII
Data File menu command and select the "Point Only" import option. Of course
you can also always see the elevation at any given location in the status
The "edginess" of the contours generated in Global Mapper is dependent on
the source elevation data, the sample spacing the contours are generated at,
and the setting on the Simplification tab of the contour generation dialog.
The Simplification tab allows you to remove what Ozi terms "redundant
points". There is a slider allowing you to configure how far off a straight
line a point has to be before it is considered "redundant" and is removed.
There is not anything in Global Mapper that will allow you to artificially
add points to a contour line feature to enhance the curvature of the line
feature (this would probably be a spline curve or something of the sort).
Typically if your source elevation data is resolute enough you will get
sufficient curves though.
Global Mapper Support
From: Maurizio [mailto:mdf@...
Sent: Sunday, April 10, 2005 3:21 PM
Subject: [global_mapper] DEM value displayed in grid and contour lines
When comparing contours generated from a DEM over an image e.g. an aerial
photo, I have noticed that at times contour lines follow a path that is not
consistent with the underlying image. Obviously the process in which
contours are generated is purely a mathematical process which might not
take into account the presence of topographic features e.g. streams.
I was wondering if there is some sort of method which could be used to
"visualize" values in a grid. What I mean is if it is at all possible to
display the grid values in a numeric rather than a graphic format so that a
point in a certain position is labelled by its elevation value.
I am not sure if I have explained correctly what I am after.
A general observation is that GM generated contours are quite "edgy" when
compared with existing contour vectors of the same resolution. Also the
number of points is very much larger.
Could anyone suggest some good point reduction program which I could try? I
am aware that OziExplorer for apply a reduction routine so that "redundant
points" are deleted i.e. points which lay between start and end points of a
straight line. However I am looking for some form of reduction program on
its own, since Ozi is not able to handle efficiently large vector files.
I was told that there is an Arcview script for the purpose: does anyone know
the name and where to find it? Is there somewhere something which could
"round" curves eliminating that "edgy" feel?
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