Global Mapper v25.0

Assign DEM heights to waypoints

Aquaflow
Aquaflow Global Mapper User
edited December 2007 in Technical Support
Using Global Mapper to create contours from SRTM DEM data
We have also loaded waypoints via a kml file
We want to assign the elevation height from the DEM file to the waypoints
How do we do this?



I see we can manually change the heights via the info tool.
It lists elevations as an attribute and then the height.
However - we want to automatically assign the elevations to a number of waypoints.

We will then take our kml file into other programs to utilise the data.

Note: The KML file contains a proposed pipeline route.
We have used kml (Google Earth) format - but could utilise others if necessary

The Contour creation and 3D is handy - althouh we are really interested in just getting elevation heights attached to these waypoints.

Regards Frank

Comments

  • global_mapper
    global_mapper Administrator
    edited December 2007
    Frank,

    What you can do after loading your KML and DEM files is switch to the Digitizer Tool, use the Edit->Select All menu command to select all of the point features, then right-click and select the edit option then remove the ELEVATION and/or HEIGHT attributes. Then, do an export to a format like a Shapefile or Simple ASCII Text file and choose to include elevations with the export. This will cause the elevation value from the underlying DEM to be used as the new file is created. Finally, load that newly created back into Global Mapper and export it to a new KML file.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Aquaflow
    Aquaflow Global Mapper User
    edited December 2007
    Mike

    We have another existing program where you simply:
    1: Select all waypoints
    2: Tools|Set Altitude from DEM

    That's it -it is that simple.

    Your suggested workaround - well it didn't quite work - it didn't bring elevations back in with it.

    In any event - there are too many steps.

    I have a number of clients who I am helping with site plan preparation.
    Global mapper can obviously provide contours from the DEM file.
    This function is quick and simple.
    However - for some - they will not want contours - rather spot heights to their waypoints.
    Unfortunately - the suggested workaround will not work in the real world
    i.e potential users would not use such a method - just too messy and too many steps.

    Not sure how easy it would be to include something in a future release.

    Regards Frank
  • Aquaflow
    Aquaflow Global Mapper User
    edited December 2007
    Mike

    I got the waypoint elevation to work via using Export Simple ASCII txt

    However - would sure like to reduce the number of steps!

    See below

    5: After you have set points for the pipeline, GPSU will open with a list of Pipeline Route Waypoints.
    • Firstly – Save the Pipeline Waypoints as a *.txt file
    • Then Save it as a *.kml file
    • (The kml file MUST contain 0 heights in the elevation column
    • Click on the Map page then left click on the middle of the Map.
    • Click on DEM icon to download the DEM Altitude data for the area.
    • Click on Get File (s). Note downloaded file name, eg S20E145.hgt
    • When Download has finished – click on Close then Close the Map.

     6: Select all waypoints via – then select TOOLS | INSERT IN ROUTE, then click on ALL

     7: Go to My Documents\Aquaflow Projects – locate the *.kml file, right click on it and select Open With: Global Mapper. (If you double left click on it, it will open in Google Earth)

     8: Go to File|Open Data File(s) and find C:\Documents and Settings\Administrator\My Documents\My GPSU\DEM and select the appropriate DEM file, example: S20E145.hgt

     9: Go to File|Export Vector Data|Export Simple ASCII text file

     10: In the Options screen, ensure “Export Elevations for Each Vertex” Box is Checked, then Click OK

     11: Save the file as a *.xyz in C:\Documents and Settings\Administrator\My Documents\Aquaflow Projects

     12: Open Tools|Control Centre, Select your KML file, then Click “Close Overlay”, then Click “YES” to the Close Overlay Message”, then click “Close” to close the Control Centre

     13: Go to File|Open Data File(s) and find C:\Documents and Settings\Administrator\My Documents\Aquaflow projects and select the *.xyz file you previously saved then click “Open”

     14: Click “Okay” x 3 Times for the Messages that appear.

     15: Go to File|Export Vector Data|Export KML/KMZ, Click “Okay” on Message, then Save as *.kmz file in C:\Documents and Settings\Administrator\My Documents\Aquaflow projects.

     16: Open this *.kmz file with GPSU and your waypoint s will now have elevations updated from the DEM data.

    Note: Your first waypoint has been renamed W000 from 001 and all subsequent waypoints have had their number reduced by one. (We will look for a solution for this).

    Note: Whilst in Global Mapper – you can also add contours then view the pipeline route in 3D to ensure the route is appropriate. Close Global Mapper when complete
  • global_mapper
    global_mapper Administrator
    edited December 2007
    You are right, that is too many steps. I have gone ahead and added an option in the Digitizer/Edit Tool to apply/update the ELEVATION attribute of selected point features using the loaded terrain data from directly within Global Mapper. Now you simply need to load your terrain and waypoint data, then select the waypoints with the Digitizer/Edit Tool, then right-click and select the option to add elevation attributes from the loaded terrain data. You can then export that directly to a new KML file.

    I have placed a new build at http://www.globalmapper.com/global_mapper9.zip with the change for you to try. Simply download that file and extract the contents into your existing v9.xx installation folder to give it a try.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Aquaflow
    Aquaflow Global Mapper User
    edited December 2007
    Mike

    Thanks - that is much easier.

    Two other issues:

    1: Can we have a zoom previous.

    2: If one has waypoints and a route - when using the digitiser tool - it can be hard to select the waypoints.

    In a CAD program I have, when there are several items with the same position, if the wrong one is selected, simply press ENTER, and in will select the next item. Simply keep pressing ENTER to scroll through the items.

    Wanting something similar - maybe a SELECT NEXT ITEM on the MODIFY FEATURE INFO menu screen

    Regards Frank
  • global_mapper
    global_mapper Administrator
    edited December 2007
    If you are using the Zoom Tool you can Ctrl+Right Click to restore your previous zoom level.

    You can disable selection of lines on the Vector Display tab of the Configuration dialog, making it easier to select waypoints when you have both routes and waypoints loaded.

    If you are using the Feature Info tool to select features, you can right-click to cycle through the features that were near your clicked location.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Aquaflow
    Aquaflow Global Mapper User
    edited December 2007
    Mike

    It will still be handy to have a Zoom Previus icon on the menu bar. Saves having to remember if it was control, or alt, or shift plus left click - or was that right.

    Another suggestion.
    I have 2 files to load, one is a kml, the other a hgt (DEM).

    It is better to load the kml first - because when you then load the DEM, the screen is still zoomed in on the kml waypoints.

    If you load the hgt first - the screen zooms to cover the whole DEM. When you then load the kml - the screen zoom doesn't change. Then you manually zoom in.

    With the above - no issues or changes required re the zoom.

    However - what would be handy is an additinal option in the menu
    "Suggest and load DEM files required for KML files"

    In addition - you might want to allow the user to set a default path were the DEM files are located - it could even load them automatically

    So if a user loads a KML file and the above option is checked,
    it will suggest the DEM file required - and take the user to the folder where the DEM is located.

    I am planning to have all DEM files for Australia located on my computer.

    Regards Frank
  • global_mapper
    global_mapper Administrator
    edited December 2007
    Frank,

    What I would suggest is using the File->Create New Map Catalog menu command to create a map catalog for all of your DEM files. You can then just load this map catalog file into Global Mapper and the underlying DEMs will automatically be loaded and unloaded as needed for display and export.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com