Global Mapper Pro

combine numeric attributes when copying attributes to area

JSL
JSL Global Mapper UserTrusted User
edited September 2014 in Vector Data
Hi, is it possible to have all the length attributes of streams be added up into a total length when copying to a polygon at their juncture? I've attached an example. I could do it by creating a separate csv file for the streams, adding all the stream lengths and joining that figure in another csv to the polygon, but I'm wondering if there's a more streamlined way to do this in GM. It would be nice to be able to do the same with any dimensional attribute, such as stream flow or area.

Thanks for any help.

Comments

  • DMcKittrick
    DMcKittrick Global Mapper Trainer Trusted User
    edited September 2014
    There is no automated function in Global Mapper for assigning the sum of the values in an attribute field to an adjacent polygon however there are a couple of tools that come close.

    Select all of the streams with the Digitizer tool, right-click and choose Analysis/Measurement > MEASURE - Display Feature Measurements. At the bottom of the resulting dialog box, you will see the total length for all of the selected lines.

    With the stream layer visible on the screen and all other layers removed or unchecked in the Overlay Control Center, click the Search button in the toolbar. In the Search Vector Data dialog box, right-click on a numeric field and choose STATS - Report Statistics for Values of [field name]. This will create statistical summary of the values in that field.

    - David McKittrick
    Senior Applications Specialist
    Blue Marble Geographics
  • JSL
    JSL Global Mapper User Trusted User
    edited September 2014
    Thank you for that information--I was unaware of the STATS feature. In my workspace, however, I've got several hundred different watersheds around the world, each with a with a custom dot polygon at their mouths into which the watershed streams feed. I'm trying to sum the length of the streams per watershed and use that figure to modify the size of the dot, so it will probably be more efficient to use my previous method:

    1. Copy the name of the polygon as an attribute to each of the streams in its watershed
    2. Export all the streams as a csv using Display Feature Measurements
    3. Create a pivot table in excel that sums the stream lengths by the polygon name
    4. Export the pivot table as a separate csv
    5. Join the pivot table with the summed lengths by the polygon name to the polygon layer, and use that figure to modify the dot size

    Thank you for your help.
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