Converting Point Data to Areas

gregleongregleon Global Mapper UserPosts: 30Trusted User
edited October 2014 in Technical Support
I have a shp file of pt data that defines a tree height/canopy area per pt. Is there a good way in GM to take each pt and create a circle or square polygon sized based on canopy sq area and also having the height mapped to the new polygon.

Comments

  • Jasmine_BMGJasmine_BMG BMG Staff Posts: 174
    edited July 2014
    Hello Gregleon,

    Do you have the canopy area as an attribute value in your shapefile? If so, it sounds like you would like to 'auto create' polygons from selected points - using an (canopy) area attribute value to define the polygon, and using the selected points as centroids for the polygons. Please let me know if this is what you are looking for.

    We have ways to add height or elevation to existing features - do you have a DEM loaded? There is an option on the right-click menu under Analysis/Measurement to Apply Elevations from terrain Layers to Selected features.

    Regards,

    Jasmine
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited July 2014
    If you can calculate an attribute named RING_RAD_M with the radius in meters for a circle centered on each point (try the CALC ATTR right-click option on the layer from the Control Center), you can select all of the points with the Digitizer Tool, then press the range ring button and select to create a ring centered on each point. The ring will use the radius from the RING_RAD_M attribute if there, so you can easily get a different radius for each point.

    Each ring should also get any other attributes from the points automatically, including the height, so you should have 3D areas at the specified height and radius just like that!

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation
  • Amanda McDermottAmanda McDermott Global Mapper User Posts: 69Trusted User
    edited October 2014
    Hello,

    I have a question that relates to this - I am trying to do something fairly similar, but I want to keep both the points and areas, and update attributes of both over time.

    Is there any way to create a hybrid point/area symbol, that would work so that if I changed an attribute of the point it would automatically change the same attribute of the linked area? Then I won't have to remember to go into each separately, and duplicate the action of updating the attribute?

    If I have to duplicate the attribute update for each of identical point and area symbols, it will take longer each time, and there is more potential for error!

    Otherwise I could delete all the areas, and re-generate the areas after updating the points each time, but I think it will be simpler if I can create an area at the same time as creating a new point, and link the attributes of the areas to the points so that the areas just auto-update?

    Thanks,
    Amanda
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