Scaling issues with the contour file when imported to AutoCAD from the file generated from WebODM

WebODM
#1

I’m new to WebODM and running it on Windows 10. I’ve successfully generated the map from the set of 61 images (300Mb in total). I’ve generated the contour file (in .dxf format). The problem I’m having is the scaling issues with the generated contour file when I import it into the AutoCAD. Below I’ve attached the image of the path measurement of the map in WebODM and AutoCAD. Can anyone help me to to figure out this problem?

Path Distance in WebODM - 245m (Left) and Path Distance in AutoCAD shows only 0.0022m (Right)

contour

Scaling issues in autocad
#2

Have you used Re-Cab to set the correct unit and scale before importing in to AutoCAD or Civil3D?

#3

@Alson_Prasai
Have you been able to figure out a work around for this issue? I’m having the same problem but do no have Recap like mentioned previously.

Thanks

#4

I am having the same issue. tried multiple resolutions to see if there was a problem with the export, and in all cases the dxf comes into AutoCAD exceptionally small. If it was just a matter of scaling it would be easy, but there seems to be something funky happening. Additionally the North-South direct seems to get squished, or the East-West direction is elongated. I’ve tried to use a known dimension to see if there was some common factor but was unable to find a correlation. I downloaded the trial of recap and it doesn’t support dxfs as far as I can tell. Any help would be much appreciated.

Image for reference: https://1drv.ms/u/s!AjBrUG9RUb7Fg6xXss48BKxVBa4EDg?e=hqflbx

#6

Hi SeanG,

Try changing CRS to UTM. You can use QGis for reprojection and then export again to a dxf file.

#7

Hi israelbar,

Forgive me I’m unfamiliar with what you are asking me to do. Is that a setting in WebODM? Are you asking me to use a different program to create DXFs?

Please advise.

#8

SeanG,

Probably the CRS in your dxf file is set to a latitude and longitude format. This means coordinates are shown in degrees with some decimal places to give some accuracy, something like DD.DDDDDDD.

What I’m proposing is to open this dxf file in QGis, reproject to a UTM coordinate system, so units can be handled as meters. Please note that units in UTM have some scale factor, but for some use cases this is not relevant.

Finally you can export this dxf file again but with a more appropriate scale.

I hope you will find this process amusing.

Saludos

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#9

Thank you israelbar! Was able to get it to work. I found that it was easier to export the contours as a GeoPackage, rather than trying to create a GeoPackage with the DXF. Changing the CRS in QGis was not straight forward but Google was able to help. Exporting to DXF was easy enough. Would like to see ODM add this ability directly rather than using a 3rd party software to accomplish the same task.

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