Global Mapper v25.0

Need Length & Slope of Line Feature PLUS discrete segments

sengg
sengg Global Mapper User
edited February 2014 in Elevation Data
I am looking for a quick way to generate 3D length and slope (%) for a Line Feature which I have segmented using the ReSample/Split Selected Feature at Specified Spacing. I get the overall line details in Analysis/Measurement and Measure / Display Feature Measurements, and that is exportable by CSV (helpful). However, it would be even better if one could drill into this for the segment by segment breakdown of the same data. Thanks.

Comments

  • DMcKittrick
    DMcKittrick Global Mapper Trainer Trusted User
    edited February 2014
    Based on the description of your workflow, you should already be seeing the slope statistics for each line segment. I suspect there is one step in the Resample/Split process that you overlooked. By default, this procedure will insert vertices at the desired locations but it will maintain the line as one feature. In the Sample Spacing dialog box, make sure to check the box next to Split into New Features at New Vertices is checked. All of the new lines should now be selected. Simply right-click and choose Attribute/Style Functions > Calculate Elevation/Slope Stats for Selected Feature(s)... This should give you separate slope information for each line segment.

    -David McKittrick
    Senior Applications Specialist

    Blue Marble Geographics
  • sengg
    sengg Global Mapper User
    edited February 2014
    Thanks, David. That, together with being able to add more features with Ctrl button permitted me to do as you suggested. Good day,
  • sengg
    sengg Global Mapper User
    edited February 2014
    I need to take this a bit further now. I am drawing several line features on my elevation grid some of which are segmented at random positions. I have been able to use the PATH PROFILE to generate a nice profile with the vertices indicated. So far so good. Would it be feasible to place on that generated profile image an average slope (%) by segment and then by entire line feature? Thanks,
  • global_mapper
    global_mapper Administrator
    edited February 2014
    What you can do is select your line feature in the Digitizer Tool, then right-click and under the Crop/Combine/Split submenu select to create a new line feature for each segment. Then select each of those segments along with the original long-line, then right-click and under Analysis/Measurement select to calculate elevation/slope statistics. This will add attributes for the elev/slope stats to each line, including the individual segment lines and the original line. Then go to the Options dialog for the layer with the lines and specify that the labels should come from the AVG_SLOPE_DEG attribute. You should then have a label on each segment for the slope.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation