I opened with QGIS the shapefile in the following archive http://data.openstreetmapdata.com/coastlines-split-4326.zip and I want to convert this shapefile to a list of latitude and longitude values for every coastline point. To do so, I opened the .shp file with QGIS, then clicked on 'lines' on the layer panel, selected 'Save as...', selected the following options enter image description here, and clicked on 'OK'.

I obtain a .csv file that looks like this

"LINESTRING (-4.94237 55.725449,-4.941922 55.725585, ... " 

May you please confirm that the pairs of numbers (e.g. -4.94237 55.725449) correspond to the GEODETIC latitude of a point and to its longitude (both in degrees), respectively?


3 Answers 3


Pasting the coordinates in Google Maps does plot a point somewhere in the ocean, and since you are using the coastline shapefile I will assume it's correct. OSM shows thisenter image description here

  • There must be something wrong here, if you zoom in to that point on Google Maps, there is no coastline...
    – James
    Commented Feb 22, 2016 at 12:36
  • Google doesn't show anything there but you are using the osm coastline data, I am updating the image to one of osm Commented Feb 22, 2016 at 12:54
  • But if you switch them for lat/lon you get google.co.uk/maps/place/…
    – Ian Turton
    Commented Feb 22, 2016 at 12:55
  • @iant the point still doesn't fall on a boundary, I would think that coastlines would either fall on the boundary between land and water or somewhere in the ocean, not inland, but I'm exactly sure how OSM coastlines work. Commented Feb 22, 2016 at 13:02

iant, I now remember that the first number is longitude, while the second one is latitude: if you swap the numbers and plot on Google Earth rather than google maps, you obtain that you are right on the boudnary

enter image description here


QGIS hasn't done anything to the numbers, so they are probably whatever they claim to be, which is lat-long points using EPSG:4326, which is a lat-long coordinate system based on the WGS84 spheroid.

If you really just want the points, there's probably a "Lines to points" option somewhere in QGIS that will convert your line features to point features, then you can save as CSV with one point per line.

I can't recall if WKT is lat-long or long-lat, but you can easily test this with a few samples...

  • There indeed is a lines to points tool. If the coastlines are polygons you would have to convert to lines before use though.
    – Kingfisher
    Commented Feb 22, 2016 at 13:18

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