GRDLANDMASK

Section: Misc. Reference Manual Pages (l)
Updated: DATE
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NAME

grdlandmask - Create "wet-dry" mask grdfile from shoreline data base.  

SYNOPSIS

grdlandmask -Gmask_grd_file] -Ixinc[m|c][/yinc[m|c]] -Rwest/east/south/north[r] [ -Amin_area/max_level ] [ -Dresolution ] [ -F ] [ -Nmaskvalues[o] ] [ -V ]  

DESCRIPTION

grdlandmask reads the selected shoreline database and uses that information to decide which nodes in the specified grid are over land or over water. The nodes defined by the selected region and lattice spacing will be set according to one of two criteria: (1) Lands vs water, or (2) the more detailed (hierarchial) ocean vs land vs lake vs island vs pond. The resulting mask grdfile may be used in subsequent operations involving grdmath to mask out data from land [or water] areas.
-G
Name of resulting output mask grd file.
-I
xinc [and optionally yinc] is the grid spacing. Append m to indicate minutes, c to indicate seconds. #include "explain_-R.txt"
 

OPTIONS

-A
Features with an area smaller than min_area in km^2 or of hierarchical level higher than max_level will be ignored [Default is 0/4 (all features)]. See DATABASE INFORMATION in the pscoast man-pages for more details.
-D
Selects the resolution of the data set to use ((f)ull, (h)igh, (i)ntermediate, (l)ow, or (c)rude). The resolution drops off by ~80% between data sets. [Default is l].
-F
Force pixel registration. [Default is grid registration].
-N
Sets the values that will be assigned to nodes. Values can be any number, including the textstring NaN. Append o to let nodes exactly on feature boundaries be considered outside [Default is inside]. Specify this information using 1 of 2 formats:
       -Nwet/dry.

       -Nocean/land/lake/island/pond.

[Default is 0/1/0/1/0 (i.e., 0/1)]. #include "explain_-V.txt"
 

EXAMPLES

To set all nodes on land to NaN, and nodes over water to 1, using the high resolution data set, do

grdlandmask -R-60/-40/-40/-30 -Dh -I5m -NNaN/1 -Gland_mask.grd -V

To make a 1x1 degree global grid with the hierarchical levels of the nodes based on the low resolution data, try

grdlandmask -R0/360/-90/90 -Dl -I1 -N0/1/2/3/4 -Glevels.grd -V
 

SEE ALSO

gmt, grdmath, grdclip, psmask, psclip, pscoast #include "refs.i"


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
SEE ALSO

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Time: 07:11:05 GMT, January 07, 2025