Counting Points in area

gregleongregleon Global Mapper UserPosts: 30Trusted User
I have created an area grid of x columns and y rows. My intent is to count the number of points in each grid cell. However, it seems that this function does not work well with large datasets, is there a known scaling problem here? Any better way to do accomplish this other than running a density grid? I would also like to do an attribute function in place of just counts, ie for each point, sum the point's attribute of interest and then tally that in the grid cell.
Thanks

Answers

  • bmg_bobbmg_bob Global Mapper Programmer Posts: 2,032
    What version of Global Mapper are you using? If you are using v16, have you updated to the latest released version?

    If the problem persists in the latest version, please send a description of your workflow, a copy of your data (if possible), and the results to Blue Marble Geographics Support (geohelp@bluemarblegeo.com). Please be specific about what you mean by "does not work well with large datasets." This will ensure that the support team sees the problem.
  • gregleongregleon Global Mapper User Posts: 30Trusted User
    I was running 16.1, upgraded to 16.2. I have a grid about 60x40km at 100m cells, 1.25M pts distributed in area. Previously I let it run for a long time and it seemed like it finished but then I could not save teh project or interact with GM in anyway. When I tried to save, it popped up hte save dialog and then disappeared..I had to esc out to get the invisible dialog to close. I eventually just had to kill in the instance. I am trying 16.2 now and will let you know how it goes.

    As a feature request, same function I am doing now but be able to do an attribute function for the points in the area..ie sum all of attribute x for each point in each cell and then add that summed attribute to the area.
  • gregleongregleon Global Mapper User Posts: 30Trusted User
    Yeah, the system continues to crash out after completing the run. I can't provide the data but it is simple to recreate the scenario based on the earlier description.
  • Jasmine_BMGJasmine_BMG BMG Staff Posts: 174
    Hello Gregleon,

    I have not been able to recreate the issue running a quick test with some Lidar data and a 100 cell grid, it took a few minutes to process, but completed successfully with a point count attribute added for each cell.

    If you would like to log a support ticket for the crash you are experiencing when running this operation, please contact Blue Marble Application Support directly at geohelp@bluemarblegeo.com.

    Regards,

    Jasmine B.
    Blue Marble Application Support
    http://www.bluemarblegeo.com/support/support.php

  • gregleongregleon Global Mapper User Posts: 30Trusted User
    Thanks for testing, please try a 250k cell grid with 1M points(lidar should have that many), that should exhibit the lock up behavior.
    Greg
  • Jasmine_BMGJasmine_BMG BMG Staff Posts: 174
    Hi Greg,

    If you need any further assistance, or would like us to log a Support Ticket for additional testing of this issue, please contact Blue Marble Application Support directly at geohelp@bluemarblegeo.com.

    Regards,

    Jasmine B.
    Blue Marble Application Support
    http://www.bluemarblegeo.com/support/support.php
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