Compare/combine DEM and DWG

rotoview

Hello Mike and all others.
I have gotten a DWGfile with contours and measurepoints from my client. I have made a DEM from my last UAVflight.
My client wants to see if theres any differences now (my DEM) and the earlier measurement (DWG).

What would the most easy way be to do a comparison between the two layers/formats?
guess one of the layers needs to be converted in any way.
DEM_vs_DWG.jpg

global_mapper

If you create a grid from your DWG file (under Analysis menu), you can then use the Analysis menu command to Combine/Compare the terrain layers and create a new subtraction surface so you can easily visualize and quantify any differences.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation

rotoview

Hello and once again, thanx for a quick reply.
But im not nearly there yet.
It turns out like this:
DEM_vs_DWG2.jpg
Some areas have no hight as i interprate this image.
What checkboxes should i and not check when creating a grid?

Johan

global_mapper

Johan,

The areas with no height, were there features in those regions with a height value of 0? If so there is an option when gridding to ignore zero elevations. That may fix the issue.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation

rotoview

Hello again Mike!
When trying to make a grid out of the clients dwg-file it turns out like this:
Why? Suggestions?
dwg_gridding.jpg

rotoview

Vatterskoga-2008-2009.zipVatterskoga-2008-2009.zip

I have attached the dwg-file in question for you to test with.
I want to make a grid thats able to be subtracted from a DEM.
My goal is to make a differential map regarding heights / elevations.
Regars
Johan, Sweden.

global_mapper

Johan,

There are a lot of points in there with bad elevations. To just get the contours, first go to the Vector Display tab of the Configuration dialog and turn off area and point display, then right-click on the layer in the Control Center and select to generate an elevation grid. Once that creates, you can then turn point and area display back on.

Thanks,

Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation

rotoview

That solved my problem :-)
Thank you! Once again speedy support!
Johan