From b155e49ccbcb395b05da53e7f046651e3c758bc3 Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Tue, 11 Nov 2025 13:33:25 +0800
Subject: [PATCH 1/3] pygmt.grdproject: Migrate the 'center' parameter to the
 alias system

---
 pygmt/src/grdproject.py | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/pygmt/src/grdproject.py b/pygmt/src/grdproject.py
index 2bf82e83dc6..e7e02b63398 100644
--- a/pygmt/src/grdproject.py
+++ b/pygmt/src/grdproject.py
@@ -7,7 +7,7 @@
 
 import xarray as xr
 from pygmt._typing import PathLike
-from pygmt.alias import AliasSystem
+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, use_alias
@@ -17,7 +17,6 @@
 
 @fmt_docstring
 @use_alias(
-    C="center",
     D="spacing",
     E="dpi",
     F="scaling",
@@ -25,10 +24,11 @@
     M="unit",
     n="interpolation",
 )
-@kwargs_to_strings(C="sequence", D="sequence")
+@kwargs_to_strings(D="sequence")
 def grdproject(
     grid: PathLike | xr.DataArray,
     outgrid: PathLike | None = None,
+    center: Sequence[float | str] | bool = False,
     projection: str | None = None,
     region: Sequence[float | str] | str | None = None,
     registration: Literal["gridline", "pixel"] | bool = False,
@@ -57,6 +57,7 @@ def grdproject(
     Full GMT docs at :gmt-docs:`grdproject.html`.
 
     {aliases}
+       - C = center
        - J = projection
        - R = region
        - V = verbose
@@ -71,13 +72,12 @@ def grdproject(
         [Default is ``False``].
     {projection}
     {region}
-    center : str or list
-        [*dx*, *dy*].
-        Let projected coordinates be relative to projection center [Default
-        is relative to lower left corner]. Optionally, add offsets in the
-        projected units to be added (or subtracted when ``inverse`` is set) to
-        (from) the projected coordinates, such as false eastings and
-        northings for particular projection zones [Default is ``[0, 0]``].
+    center
+        If ``True``, let projected coordinates be relative to projection center [Default
+        is relative to lower left corner]. Optionally, set offsets (*dx*, *dy*) in the
+        projected units to be added (or subtracted when ``inverse`` is set) to (from)
+        the projected coordinates, such as false eastings and northings for particular
+        projection zones [Default is ``(0, 0)``].
     {spacing}
     dpi : int
         Set the resolution for the new grid in dots per inch.
@@ -120,7 +120,9 @@ def grdproject(
         msg = "Parameter 'projection' must be specified."
         raise GMTInvalidInput(msg)
 
-    aliasdict = AliasSystem().add_common(
+    aliasdict = AliasSystem(
+        C=Alias(center, name="center", sep="/", size=2),
+    ).add_common(
         J=projection,
         R=region,
         V=verbose,

From e2c0eb2989486e51ec7e3e46b14a23ef854e6494 Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Tue, 11 Nov 2025 16:21:14 +0800
Subject: [PATCH 2/3] Update pygmt/src/grdproject.py
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Yvonne Fröhlich <94163266+yvonnefroehlich@users.noreply.github.com>
---
 pygmt/src/grdproject.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygmt/src/grdproject.py b/pygmt/src/grdproject.py
index e7e02b63398..a65fea23e23 100644
--- a/pygmt/src/grdproject.py
+++ b/pygmt/src/grdproject.py
@@ -73,8 +73,8 @@ def grdproject(
     {projection}
     {region}
     center
-        If ``True``, let projected coordinates be relative to projection center [Default
-        is relative to lower left corner]. Optionally, set offsets (*dx*, *dy*) in the
+        If ``True``, let the projected coordinates be relative to the projection center [Default
+        is relative to the lower left corner]. Optionally, set offsets (*dx*, *dy*) in the
         projected units to be added (or subtracted when ``inverse`` is set) to (from)
         the projected coordinates, such as false eastings and northings for particular
         projection zones [Default is ``(0, 0)``].

From 57463a2ff0eeea6f74eb2f910fd29b004a85b8db Mon Sep 17 00:00:00 2001
From: Dongdong Tian <seisman.info@gmail.com>
Date: Tue, 11 Nov 2025 16:23:49 +0800
Subject: [PATCH 3/3] Fix styling

---
 pygmt/src/grdproject.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/pygmt/src/grdproject.py b/pygmt/src/grdproject.py
index a65fea23e23..7678ab42d63 100644
--- a/pygmt/src/grdproject.py
+++ b/pygmt/src/grdproject.py
@@ -73,11 +73,11 @@ def grdproject(
     {projection}
     {region}
     center
-        If ``True``, let the projected coordinates be relative to the projection center [Default
-        is relative to the lower left corner]. Optionally, set offsets (*dx*, *dy*) in the
-        projected units to be added (or subtracted when ``inverse`` is set) to (from)
-        the projected coordinates, such as false eastings and northings for particular
-        projection zones [Default is ``(0, 0)``].
+        If ``True``, let the projected coordinates be relative to the projection center
+        [Default is relative to the lower left corner]. Optionally, set offsets
+        (*dx*, *dy*) in the projected units to be added (or subtracted when ``inverse``
+        is set) to (from) the projected coordinates, such as false eastings and
+        northings for particular projection zones [Default is ``(0, 0)``].
     {spacing}
     dpi : int
         Set the resolution for the new grid in dots per inch.