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I am trying to measure the distances from points in the ocean to land and these distances need to be measure from the point at different compass bearings (i.e. every 5 degrees).

I am using QGIS V2.18.21

I am working from an estimated central location of London array, Longitude 1.4950, Latitude 51.6270. I would like to understand how to measure the distances from this point to the coastline, which I have as a vector polygon layer, at a every 5 degrees on a compass.

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    Welcome to GIS Stackexchange. You'll be more likely to get helpful responses to your question if you describe some of the steps you've tried and where you've got stuck. Even better if you provide a concrete example that people can help you solve. In this case the lat long of your ocean point and the bearings to measure from.
    – RoperMaps
    Commented Jul 20, 2018 at 10:08
  • Thank you @Kazuhito it has worked and I am getting the information I needed. Commented Jul 20, 2018 at 13:13
  • If Kazuhito's suggestion has worked then click the little grey tick to the left of the answer to indicate a correct answer. Commented Jul 20, 2018 at 13:36
  • Thanks for the help, I'm new to the site so didn't know that. Commented Jul 20, 2018 at 13:41
  • Thank you Ed @EdRollason and Greg, much appreciated. Will try to answer the comment soon, too.
    – Kazuhito
    Commented Jul 20, 2018 at 13:55

1 Answer 1

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You can use Shape Tools plugin - Azimuth, Distance Tool, so that you can draw lines and calculate their distances on the geographic coordinate system (i.e. latlong).

(1) Before starting the tool, please prepare a blank line layer (CRS WGS84 - EPSG:4326). Click on this layer to start Editing mode. Keep this layer selected and highlighted.

(2) Click on the Shape Tools Azimuth Distance Digitizer icon.

(3) Click on the starting point, in London. This will activate the window (4).

(4) Enter Azimuth and give an appropriate distance (enough length to reach the coast). Click OK. A line will be drawn toward the designated azimuth.

enter image description here

(5) Repeat (3) -(4) until you get all required lines.

enter image description here

(6) Clip the Line layer (Greg_Lines in the above example) by the coastline polygon.

(7) Calculate the length of clipped lines by the Field Calculator ($length).

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  • Would this give the length in meters or another unit? Commented Jul 20, 2018 at 13:39
  • @GregPalmer To see the current measurement settings, please go to Project | Project Properties | General (tab). You will find Measurements.
    – Kazuhito
    Commented Jul 20, 2018 at 13:59

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