Make coordinates optional in `extr_map.nc`

Preparing for a non-uniform longitude latitude grid.

Common/Tests/write_extr_map.f90

@@ -11,8 +11,8 @@ contains
          nf95_def_var, nf95_put_att, nf95_enddef
 
     integer, intent(in):: extr_map(:, :) ! map of extrema
-    real, intent(in):: longitude(:) ! in degrees
-    real, intent(in):: latitude(:) ! in degrees
+    real, intent(in), optional:: longitude(:) ! in degrees
+    real, intent(in), optional:: latitude(:) ! in degrees
 
     ! Local:
     integer ncid, varid_lat, varid_lon, varid_extr_map, dimid_lat, dimid_lon
@@ -24,21 +24,25 @@ contains
     call nf95_def_dim(ncid, "lat", size(extr_map, 2), dimid_lat)
     call nf95_def_dim(ncid, "lon", size(extr_map, 1), dimid_lon)
 
-    call nf95_def_var(ncid, "lat", NF90_FLOAT, dimid_lat, varid_lat)
-    call nf95_put_att(ncid, varid_lat, "standard_name", "latitude")
-    call nf95_put_att(ncid, varid_lat, "units", "degrees_north")
+    if (present(latitude)) then
+       call nf95_def_var(ncid, "lat", NF90_FLOAT, dimid_lat, varid_lat)
+       call nf95_put_att(ncid, varid_lat, "standard_name", "latitude")
+       call nf95_put_att(ncid, varid_lat, "units", "degrees_north")
+    end if
 
-    call nf95_def_var(ncid, "lon", NF90_FLOAT, dimid_lon, varid_lon)
-    call nf95_put_att(ncid, varid_lon, "standard_name", "longitude")
-    call nf95_put_att(ncid, varid_lon, "units", "degrees_east")
+    if (present(longitude)) then
+       call nf95_def_var(ncid, "lon", NF90_FLOAT, dimid_lon, varid_lon)
+       call nf95_put_att(ncid, varid_lon, "standard_name", "longitude")
+       call nf95_put_att(ncid, varid_lon, "units", "degrees_east")
+    end if
 
     call nf95_def_var(ncid, "extr_map", NF90_INT, [dimid_lon, dimid_lat], &
          varid_extr_map)
 
     call nf95_enddef(ncid)
 
-    call nf95_put_var(ncid, varid_lon, longitude)
-    call nf95_put_var(ncid, varid_lat, latitude)
+    if (present(longitude)) call nf95_put_var(ncid, varid_lon, longitude)
+    if (present(latitude)) call nf95_put_var(ncid, varid_lat, latitude)
     call nf95_put_var(ncid, varid_extr_map, extr_map)
 
     call nf95_close(ncid)