Global Mapper v25.0

Go from LAS preview to full data in limited area?

kfroese
kfroese Geotechnical EngineerTrusted User
edited June 2012 in Technical Support
I have a large LAS file (2.7Gb) I'm trying to process (64bit version, i7 with 8Gb RAM). I can't open it directly or via Batch Convert without a significant wait (I have given up at the 15% mark when GM seemed to hang with no further increase in progress). I did use the "preview" mode which allowed me to open the data quite nicely for a quick view. (Also saw this discussed in http://www.globalmapperforum.com/forums/suggestion-box/4621-quick-view-las-files.html).

What I am wondering, one I have the "preview" data, could I draw an area and then get GM to go get the full data for that limited area? As in this particular case, I know there is a definite subset of the area that I want full resolution and I don't care about the rest of the data.

Comments

  • global_mapper
    global_mapper Administrator
    edited May 2012
    There isn't a way currently to limit what you load to a box, but I am surprised that you are having problems like that in the 64-bit version. What version are you using? I presume you are loading as a point cloud, correct? If you go to Task Manager how much memory is it using?

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • kfroese
    kfroese Geotechnical Engineer Trusted User
    edited May 2012
    I'm using version 13.2.0 (May 16 2012 12:18:17) with 8 Gb RAM. GM is using about 6.4Gb (which is all that is left) of it when processing this file. My memory usage was at 99%.

    I noted in that other thread I alluded to that you stated it wasn't very difficult to selectively pick points out of the LAS data which is how the "preview" mode of every 10th point came to be. I was wondering if a similar strategy could be employed to select out an area: each point could be queried to see if it falls within a selected bounding box - if it does, then load it; if not, skip it.
  • global_mapper
    global_mapper Administrator
    edited May 2012
    Ok I guess you are just running out of memory. I have added a task list item to add a bounding box selection to the Lidar import options so you can restrict your area of interest and just load that in. I'll let you know when that is available.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • global_mapper
    global_mapper Administrator
    edited June 2012
    I added an option during the Lidar import do specify a filter rectangle so you can easily just load a portion of the data. I have placed a new build at http://www.globalmapper.com/global_mapper13.zip with the latest changes for you to try. Simply download that file and extract the contents into your existing v13.xx installation folder to give it a try. If you are using the 64-bit v13 version there is a new build at http://www.globalmapper.com/global_mapper13_64bit.zip .

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com