Converting grid corners from UTM to degrees, minutes, and second in QGIS

Question

I have a shapefile of a 10km grid that is in UTM projection but I would like to convert all coordinates to Degrees, Minutes, and Seconds. The attribute table has corners (Top, Bottom, left, and right). These are the ones I would like to convert to DMS. How can I do that in QGIS?

I tried to save as CSV but I did not get the coordinates of all corners. I have also used 'add geometry attribute' but it also did not give the DMS coordinates.

Here is how the grid looks like:

Answer 1

You can use these expressions:

left:

to_dms(x_min(transform($geometry,layer_property(@layer,'crs'),'EPSG:4326')),'x',3)

top:

to_dms(y_max(transform($geometry,layer_property(@layer,'crs'),'EPSG:4326')),'y',3)

right:

to_dms(x_max(transform($geometry,layer_property(@layer,'crs'),'EPSG:4326')),'x',3)

bottom:

to_dms(y_min(transform($geometry,layer_property(@layer,'crs'),'EPSG:4326')),'y',3)

• The last number (3 in my example) specifies the coordinate precision. Change that if you want to.
• You can also add ,'aligned' or ,'suffix' behind the coordinate precision to format your output. E.g. to_dms(y_min(transform($geometry,layer_property(@layer,'crs'),'EPSG:4326')),'y',3,'suffix')
• Note that your output field must be of type string

Further explanation: First we get the geometry by using $geometry and transform() it from the layers source CRS (layer_property(@layer,'crs')) to WGS84 ('EPSG:4326'). Then we get the max or min coordinates by using x_min(), y_max() and so on, which are equal to left, top, etc.. Finally we convert the transformed coordinate to degree, minute and second by using to_dms(). See QGIS docs for information about this expression: https://docs.qgis.org/3.16/en/docs/user_manual/working_with_vector/functions_list.html#to-dms