From 716416376c01c8394a062037522b05ec6aa6343e Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Wed, 30 Jul 2025 19:14:01 +0800
Subject: [PATCH 1/2] pygmt.grdlandmask: Refactor to use the new alias system
 for bordervalues/maskvalues

---
 pygmt/src/grdlandmask.py | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/pygmt/src/grdlandmask.py b/pygmt/src/grdlandmask.py
index f2fdae251d9..6065424f621 100644
--- a/pygmt/src/grdlandmask.py
+++ b/pygmt/src/grdlandmask.py
@@ -7,13 +7,13 @@
 
 import xarray as xr
 from pygmt._typing import PathLike
+from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
 from pygmt.exceptions import GMTInvalidInput
 from pygmt.helpers import (
     build_arg_list,
     fmt_docstring,
     kwargs_to_strings,
-    sequence_join,
     use_alias,
 )
 from pygmt.src._common import _parse_coastline_resolution
@@ -25,9 +25,7 @@
 @use_alias(
     A="area_thresh",
     D="resolution-",
-    E="bordervalues-",
     I="spacing",
-    N="maskvalues-",
     R="region",
     V="verbose",
     r="registration",
@@ -55,6 +53,8 @@ def grdlandmask(
     Full GMT docs at :gmt-docs:`grdlandmask.html`.
 
     {aliases}
+       - E=bordervalues
+       - N=maskvalues
 
     Parameters
     ----------
@@ -119,11 +119,14 @@ def grdlandmask(
         raise GMTInvalidInput(msg)
 
     kwargs["D"] = kwargs.get("D", _parse_coastline_resolution(resolution))
-    kwargs["N"] = sequence_join(maskvalues, size=(2, 5), name="maskvalues")
-    kwargs["E"] = sequence_join(bordervalues, size=(1, 4), name="bordervalues")
+
+    aliasdict = AliasSystem(
+        N=Alias(maskvalues, name="maskvalues", sep="/", size=(2, 5)),
+        E=Alias(bordervalues, name="bordervalues", sep="/", size=(1, 4)),
+    ).merge(kwargs)
 
     with Session() as lib:
         with lib.virtualfile_out(kind="grid", fname=outgrid) as voutgrd:
-            kwargs["G"] = voutgrd
-            lib.call_module(module="grdlandmask", args=build_arg_list(kwargs))
+            aliasdict["G"] = voutgrd
+            lib.call_module(module="grdlandmask", args=build_arg_list(aliasdict))
             return lib.virtualfile_to_raster(vfname=voutgrd, outgrid=outgrid)

From 070d8e88c7b3fea9050715036b4216d6d124c6df Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Thu, 31 Jul 2025 16:42:29 +0800
Subject: [PATCH 2/2] bordervalues should be scalar or a sequence with 4 values

---
 pygmt/src/grdlandmask.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pygmt/src/grdlandmask.py b/pygmt/src/grdlandmask.py
index 6065424f621..53e4df5dc6e 100644
--- a/pygmt/src/grdlandmask.py
+++ b/pygmt/src/grdlandmask.py
@@ -122,7 +122,7 @@ def grdlandmask(
 
     aliasdict = AliasSystem(
         N=Alias(maskvalues, name="maskvalues", sep="/", size=(2, 5)),
-        E=Alias(bordervalues, name="bordervalues", sep="/", size=(1, 4)),
+        E=Alias(bordervalues, name="bordervalues", sep="/", size=4),
     ).merge(kwargs)
 
     with Session() as lib: