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I need to store the z value for hiking paths. I have the GPS coordinates (points) and the tracks (polylines). I know I can store elevation data easily with the points but are there any ways of storing elevation data with polylines?

I would like to avoid having to make a huge table of a gigantic collection of points so I would prefer to only store the tracks. I am using QGIS.

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If you add the GPS data to QGIS as a GPX file, it will load as a set of points with Z (elevation) values (PointZ).

Using the Points to Path tool from Processing (quickest access using ctrl-K or cmd-K to search), select the added layer: enter image description here The only challenge is getting the 'order' field correct (and it's not optional); many GPS units don't save a date/time to the 'time' field in the GPX, sometimes saving it in the 'cmt' or 'desc' fields, which are often overwritten with descriptive text. You may have to make a new version of the layer (select-all then Edit | Paste Features As | Temporary scratch layer) and add an 'order' column and add integer values to set the order you want to use.

The output will be a LineStringZ geometry with X, Y, Z where the Z value comes from the elevation at that point.

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  • I have done this, but where does the polyline store the elevation data? is it embedded in the geometry?
    – Hailey
    Jul 23 '20 at 15:24
  • See the updated answer! It's embedded. You might want to look into a python script like gpx2spatialite for storing track (line) and trackpoint (point) data from GPX files in a single spatialite database if you want to develop a better system for recording lots of GPS data.
    – Simbamangu
    Jul 24 '20 at 13:01
  • great advice! I am however using a SQL database and PostGIS. Do you know of any way to store GPS data using a similar method?
    – Hailey
    Jul 27 '20 at 9:26
  • There is. If it doesn't apply, ask a new question perhaps!
    – Simbamangu
    Jul 30 '20 at 16:50

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