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So I am trying to calculate the distance of several points to a coastline, using hub distance (mmqgis plugin) in Qgis Dufour 2.01. I am using the default coordinate system (WGS84) and I, already, transform the land in nodes in order to not get the centroid distance.

Problem is, I am not allowed to select the units. Please I need help with this. Normally I use ArcGIS but I realy want start to use freeware. (see the print-screens)

Coordinate system

Coastline nodes

Project settings

hub distance attempt (locked units)

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1 Answer 1

WGS84 always has degrees as units. It has little use to change the unit to metres in the Setttings, general tab. That will not perform a transformation to any projected CRS.

If you want metres, you can

  • set the project CRS to the UTM zone of your study area. This might not work for all use cases, when calculations are done with the original shapefile data.

or

  • reproject the data to that CRS (or any other projected CRS that is used in the target area)
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I have the same issue as mentioned above even when using a projected CRS. Can you explain a little more because when using ArcGIS it is perfectly possible to calculate distances with WGS84 World Mercator. –  Dspanes Nov 26 '13 at 10:05
1  
WGS84 World Mercator is not the same as WGS84. That Projection (as used by Google) has only real metres as units at the equator. The more to the poles you come , the greater the difference is. And it uses a sphere instead of an ellipsoid. That's why I don't trust measurements in World Mercator. –  Andre Joost Nov 26 '13 at 10:39

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