Calculate Flattened Site Plan Grid from Selected Area(s)

946
946 Global Mapper UserTrusted User
in Elevation Data

Hello,

Is there a way to control the output resolution for "Calculate Flattened Site Plan Grid from Selected Area(s)"?

I am calculating some filed of view area using this tool and I would like to create areas from output elevation grids. The resolutions seems to be connected to the length of area used in computation as you can see in the print attached. Base DTM is 10m pixel.

GM.jpg


Thanks,

R

Best Answer

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User
    Answer ✓

    I took a look in the code and found that the resolution of the flattened grid will try and default to the resolution of the terrain data being used, but also tries to clamp the pixel size of the full grid (before shrinking to the flattened area) to a range of 1024-8192 pixels in either dimension.

    I think the long-skinny nature of your flattened areas is causing those pixel limits to initially be hit, resulting in lower resolution.

    We do internally support using a specific spacing, but that doesn't seem to be exposed anywhere in the user interface. So we would have to make a software update to allow specifying the resolution to sample at.

    Thanks,

    Mike

    Global Mapper Guru

Answers

  • 946
    946 Global Mapper User Trusted User

    Thanks for your answer, Mike.

    Just to add some context, the tool is not used for it s main purpose but instead to check the covered area at ground level for a projected flight line (lidar,photo mission). I am creating a small buffer of the the line at a specific height and using the system field of view angle for fill and cut slope around to obtain in the end an elevation grid that will intersect the terrain, giving the limit of the covered area for one flight line. Doing this for adiacent flight lines I can notice possible gaps, due to the relief, before the real flight mission.

    It will be nice if for a future version to have the option to create separate grids for separated areas. At this point, if I select all areas (representing buffers of flight lines) the elevation grid will be created "in the air" by combining the resulted grids before touching the ground.

    In case exist already a better way to do this please let me know.

    GAPS.jpg


    Thanks,

    Robert

  • CarrickCon
    CarrickCon

    Hi Guys,

    I for one would vote 100% 👍️if you were to "make a software update to allow specifying the resolution to sample at". I use GM lots for 3D design of civil/mining earthworks and being able to control the pixel size would be awesome!

    My workaround is to create a "TERRAIN" first as the "Create Flattened Site Plan Grid" seems to default to the resolution of Terrain and the TERRAIN tool allows the user to "Manually Specify the Grid Spacing".

    Thanks,

    /al

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User

    I've created an internal ticket (GM-20859) for adding this option to an upcoming release of Global Mapper.

    Thanks,

    Mike

    Global Mapper Guru

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