Converting coordinates from meters to decimal degrees in QGIS?

Question

I have a shapefile. The coordinates (Lat/Long) are projected as meter (555000, 155000). But, I want to re-project it to decimal degrees(51.523666, -0.07467).

How can I do it with QGIS?

Answer 1

In QGIS, it's very straightforward. First, ensure that you have the correct coordinate system for your original shapefile:

1. Add the layer to the map canvas;
2. Right-click on the layer and select "Set layer CRS";
3. Choose the correct coordinate reference system (CRS) from the list - it is probably in UTM (a metric grid) and you will have to know the zone and datum for the data; it may be already automatically selected!

After this:

1. You right-click on the layer and select "Save as ...":
2. Click 'Browse' near CRS in the resulting dialog and select WGS84 EPSG:4326 as the CRS for the new file - this will save it with decimal degrees as the coordinate system.

It's a very good idea to make sure you select a good name in the "Save as" dialog - appending the coordinate system to the name can be very helpful, e.g. my_shape_file_DD_WGS84 to remember that it's in degrees, WGS84.

Answer 2

I would just add as a step 3:

3) Once the layer is re-projected in WGS84 ESPG:4326, go to Vector > Geometry Tools > Add Geometry Attributes (Calculate Using Layer CRS)

• This will add an X_Field and Y_Field attribute column to your attribute table, that displays the coordinates in decimal degrees