Global Mapper v24.0

Huge difference between laserscan (DSM) and photogrammetry (DSM)

Hello,

I use laser scanning as well as photogrammetry. Now I compared a DSM from Global Mapper (generated from a point cloud) and a DSM from Agisoft Metashape and the difference is huge. Since I am not that experienced in using this technique I wanted to ask if this is the normal difference between the two approaches or if there is something I can do differently with Global Mapper?


DSM Metashape


DSM Global Mapper


Settings Grid Creation


Answers

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User

    It looks like the AGISoft DSM may have been generated at a higher resolution than the Global Mapper DSM. Try reducing the 'Automatic Spacing Multiple' setting in Global Mapper to 1 or even 0.5 point spacings and see how that looks. Or, if you know the spacing in meters that AGISoft is using, enter that value.

    AGISoft may also be using some kind of smoothing to display the grid. You can try using different resampling methods on the generated grid layer in Global Mapper. These are on the Display tab of the Options dialog for a layer. The Gaussian Blur or Filter/Noise/Median resampling options might work well.

    Thanks,

    Mike

    Global Mapper Guru

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