I have created a DEM file, which I am using to draw a cross section along a line to see the variation of height from point A to point B along land seen below. enter image description here

When it use the Profile tool on the DEM file, it produces a cross-sectional area as seen below. enter image description here

I noticed from the profile that the elevation variation is correct, but my distance is out massively. A, because it doesn't give me units along the x-axis. B, because when I measure the same distance line from point A to point B on Google Maps, it gives me an accurate data which is massively out from the scale provided from using the profile tool.

Does anyone know why this is happening or how to fix it?

The steps I have taken to get to where I am now is..

  1. Downloaded 'OSTerrain 50' ESRI shapefile from https://www.ordnancesurvey.co.uk/opendatadownload/products.html#TERR50

  2. I converted the Contours from line.data to point.data as seen in the answer given in Creating DEM Contour files from shapefile line data in QGIS

  3. this allowed me to create a DEM file using the SAGA Triangulation tool. from this I created a cross-sectional profile.

The line I am requiring a cross-section profile of is starting at coordinates --> 60.471758, -1.291595 and ending 60.466071, -1.272155

I am using QGIS V 3.4

  • 2
    Please Edit the question to specify the spatial reference you are using to produce your cross-section.
    – Vince
    Commented Jul 31, 2019 at 15:08
  • What is the distance obtained from Google Maps? From the Profile Toole is 0,02? Commented Jul 31, 2019 at 15:58
  • It seems that the distance is in decimal degrees. Try using a CRS that define the coordinate measuring units are in meters or degrees, Commented Aug 1, 2019 at 1:03
  • why not use the DTM ASCII grid version of the dataset directly? Also your terrain data is in EPSG:27700 and metres so you may have missreprojected it somewhere
    – Ian Turton
    Commented Aug 1, 2019 at 7:44
  • I have downloaded the DTM ASCII grid version, but I am unable to upload the file to QGIS, do you know why this is the case, or how to upload a ASCII file?
    – Louis Tate
    Commented Aug 5, 2019 at 15:00


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