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I am trying calculate elevations of points (which I collected via GPS on phone) to save as a base line of study area. Here is what I did: First, input the points as geotagged images to QGIS. Second, load the Digital Elevation Model (the link I have sent in last mail) via WMS Service to QGIS. But I can't calculate elevations of points from DEM which loaded. Is there any solution to that?

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  • Can you give an example of your GPS data from your phone - normally the elevation is available *NMEA format gpsworld.com/what-exactly-is-gps-nmea-data
    – Mapperz
    Commented Mar 19 at 21:20
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    WMS is usually delivering a rendered image of DEM, not the real DEM data. Acquire the DEM from WCS or as file download. Then you can use some of the point sampling tools luisalucchese.com/post/sampling-raster-values-points.
    – user30184
    Commented Mar 19 at 22:02
  • GPS data from my phone gives Lat, Long and Altitude but I want to know the exact number above sea level.
    – Hanna
    Commented Mar 20 at 11:17
  • Easiest to download the surface model like user30184 says, then use the point sampling tool. Still, this elevation is unlikely to be expressed in a tidal vertical datum. You could try using vDatum to convert the phone's WGS84 elevation values to the tidal datum of your choice.
    – GBG
    Commented Mar 20 at 14:22

2 Answers 2

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WMS layers are generally rendered images and seldom contain raw data. Instead of using WMS, download freely available DEM data like ASTER, SRTM or Cartosat. Load this in your project along with your point layer. Then inside the Processing Toolbox, select Raster Analysis > Sample Raster Values . Choose your point layer as Input layer and DEM layer as Raster Layer. Add output column prefix [optional] and then click Run. Now a new point layer having an additional column of elevation values is generated. This algorithm basically samples the raster layer along all points in the point layer.

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As others have stated, obtaining elevation raster datasets is your best bet (and I would say fastest option). Depending on the region of the world you are working in, there are a variety of elevation surfaces available on Google Earth Engine. Here is a curated list of elevation datasets.

In case you go down that route, here is a tutorial for exporting images such as this to your Google Drive.

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