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