Land Sea Masking Scripts

Matlab: Land/Sea Masking Scripts

This page describes several Matlab scripts in the matlab/landmask repository sub-directory, which are used to process ROMS Land/Sea mask.

add_coastline.m

Adds coastline data to ROMS Grid NetCDF file. This is the coastline data used to facilitate Land/Sea masking editing.

add_coastline  (ncfile, Clon, Clat)

On Input:

ncfile:	ROMS Grid NetCDF file name (string)
Clon:	Coastline longitude (1D array, degree_east)
Clat:	Coastline latitude (1D array, degree_north)

editmask.m

GUI for manual editing of ROMS Land/Sea mask on RHO-points. To accelerate the processing, the Land/Sea mask is edited in (I,J) grid coordinates. If the (I,J) coordinates are not provided, it will compute and write them into a file. If called without one or both arguments, it will prompt for the needed file name(s). If the coastline data is in grid_file, it will read it and convert to (I,J) fractional coordinates.

editmask  (grid_file, coast_file)

On Input:

grid_file:	ROMS Grid NetCDF file name containing the grid and mask arrays (string)
coast_file:	Matlab file name containing the coastline (lon, lat) or (I,J) fractional coordinates (string; optional)

Mouse shortcuts:

double click:	zoom in
right click:	zoom out
middle click:	change editing mode

editscope.m

GUI for manual editing of ROMS adjoint sensitivity scope mask on RHO-points. To accelerate the processing, the Land/Sea mask is edited in (I,J) grid coordinates. If the (I,J) coordinates are not provided, it will compute and write them into a file. If called without one or both arguments, it will prompt for the needed file name(s). If the coastline data is in grid_file, it will read it and convert to (I,J) fractional coordinates.

editscope  (grid_file, coast_file)

On Input:

grid_file :	ROMS Grid NetCDF file name containing the grid and mask arrays (string)
coast_file:	Matlab file name containing the coastline (lon, lat) or (I,J) fractional coordinates (string; optional)

Mouse shortcuts:

double click:	zoom in
right click:	zoom out
middle click:	change editing mode

ijcoast.m

Converts coastline data to ROMS (I,J) fractional coordinates to facilitate Land/Sea masking editing with editmask.

C = ijcoast  (ncfile, coast_file)

On Input:

ncname:	ROMS grid NetCDF file name (string)
coast_file:	Coastline file name (string)

On Output:

C:	Coastline data (struct array)

C.grid	ROMS Grid NetCDF file name
C.coast	Coastline file name
C.indices	Coastline indices file name
C.lon	Coastline longitudes
C.lat	Coastline latitudes
C.Icst	Coastline I-grid coordinates, (0:L)
C.Jcst	Coastline J-grid coordinates, (0:M)

landsea.m

Computes the Land/Sea mask for an application grid atomatically and writes it into an input NetCDF file. The Land/Sea mask is computed from closed coastlines polygons extracted from the GSHHS data set if the (clon, clat) coastline data is not provided.

F = lansea  (ncfile, clon, clat)

On Input:

ncname:	ROMS grid NetCDF file name (string)
clon:	Coastline longitude (1D array; degrees_west)
clat:	Coastline latitude (1D array; degrees_north)

On Output:

F:	Land/Sea mask data (struct array)

F.mask_rho	Mask on ρ-points (2D array)
F.mask_psi	Mask on ψ-points (2D array)
F.mask_u	Mask on u-points (2D array)
F.mask_v	Mask on v-points (2D array)

read_mask.m

Reads in ROMS grid bathymetry and Land/Sea mask at ρ-point from NetCDF file.

[spherical, x, y, bath, rmask] = read_mask  (ncfile)

On Input:

ncname:

ROMS grid NetCDF file name (string)

On Output:

spherical:	Spherical switch (logical)
x:	X-location of ρ-points
y:	Y-location of ρ-points
bath:	Bathymetry at ρ-points
rmask:	Land/Sea mask at ρ-points

read_scope.m

Reads in ROMS grid bathymetry and adjoint sensitivity scope mask at ρ-points from NetCDF file.

[spherical, x, y, bath, rmask] = read_mask  (ncfile)

On Input:

ncname:

ROMS grid NetCDF file name (string)

On Output:

spherical:	Spherical switch (logical)
x:	X-location of ρ-points
y:	Y-location of ρ-points
bath:	Bathymetry at ρ-points
rmask:	Land/Sea mask at ρ-points

uvp_masks.m

Computes the Land/Sea masks at u-, v-, and ψ-points from the mask on ρ-points.

[umask, vmask, vmask] = uvp_masks  (rmask)

On Input:

rmask:

Land/Sea mask on ρ-points (2D array)

On Output:

umask:	Land/Sea mask on u-points (2D array)
vmask:	Land/Sea mask on v-points (2D array)
rmask:	Land/Sea mask on ψ-points (2D array)

uv_scope.m

Computes the adjoint sensitivity scope masks at u- and v-points from the scope mask on ρ-points.

[Uscope, Vscope] = uvp_masks  (Rscope)

On Input:

Rscope:

Scope mask on ρ-points (2D array)

On Output:

Uscope:	Scope mask on u-points (2D array)
Vscope:	Scope mask on v-points (2D array)

write_mask.m

Writes out Land/Sea mask data into ROMS Grid NetCDF file.

status = write_mask  (ncfile, rmask, umask, vmask, pmask)

On Input:

ncname:	ROMS grid NetCDF file name (string)
rmask:	Land/Sea mask on ρ-points (2D array)
umask:	Land/Sea mask on u-points (2D array)
vmask:	Land/Sea mask on v-points (2D array)
pmask:	Land/Sea mask on ψ-points (2D array)

On Output:

status:

Error flag

write_scope.m

Writes out adjoint sensitivity scope mask data into ROMS Grid NetCDF file.

status = write_mask  (ncfile, Rscope, Uscope, Vscope)

On Input:

ncname:	ROMS grid NetCDF file name (string)
Rscope:	Adjoint sensitivity scope mask on ρ-points (2D array)
Uscope:	Adjoint sensitivity scope mask on u-points (2D array)
Vscope:	Adjoint sensitivity scope mask on v-points (2D array)

On Output:

status:

Error flag