Global Mapper v25.0

Loading Las - checking Las file with point formats 1-5 has classes over 31


I am hoping someone can simply explain to me the Bolded wording below which is taken from when I load a Las dataset:

I have a set of Las data that does not show a particular classification (#150 in my dataset) even if I select 'show all classifications' when loading the file. The data is not in my viewer and if I select the pixels and look under statistic classifications, #150 it is not listed.

However, if I click the option 'Las/Laz file with point format 1-5 classes over 31' then I see the data (#150 in this case) classified in my view.

In both instances I get the attached message before GM loads the data



Why can't I see the classified files unless I choose the bolded option above? Is the 150 classifications somehow embedded in the first 5 classifications - is that what this means?


Thank you!

Answers

  • It seems classifications disabled on the configuration screen configuration. Enable all and you won't see this message.

  • When you import a point cloud, you'll be presented with this dialogue. This will control what is actually loaded in to global mapper from your file:


    After those points are loaded in, you have the option to filter the classes & returns (assuming you imported them in the first dialogue) using this option:


    To summarize, one dialogue is everything you're importing, the other dialogue is everything you're currently displaying/filtering from the imported file once it's loaded.



    Lastly (and I'm guessing here), the reason the option exists to restrict import to classes 1-31 is because those are industry/file format standards. In just about any point cloud software you use, "2" will be ground, "17" will be bridge, etc. Any classification outside of the standard classicization could be any number of things, depending on the person preparing it. A team working on one project might decide that classification 130 is for wolverines and classification 131 is for meercats. On another project, they might decide that 130=sedans and 131=SUVs. Think of them as variables set by the person/people preparing & processing the lidar dataset.