Handle image kind in _load_remote_dataset function

Special case `earth_day` to be loaded as GMT_IMAGE rather than GMT_GRID. Need to use `GMT_OUT|GMT_IS_REFERENCE` in virtualfile_out to avoid segfault, xref #3115.

Author: weiji14

pygmt/clib/session.py

@@ -1697,7 +1697,9 @@ def virtualfile_from_data(
 
     @contextlib.contextmanager
     def virtualfile_out(
-        self, kind: Literal["dataset", "grid"] = "dataset", fname: str | None = None
+        self,
+        kind: Literal["dataset", "grid", "image"] = "dataset",
+        fname: str | None = None,
     ):
         r"""
         Create a virtual file or an actual file for storing output data.
@@ -1754,8 +1756,11 @@ def virtualfile_out(
             family, geometry = {
                 "dataset": ("GMT_IS_DATASET", "GMT_IS_PLP"),
                 "grid": ("GMT_IS_GRID", "GMT_IS_SURFACE"),
+                "image": ("GMT_IS_IMAGE", "GMT_IS_SURFACE"),
             }[kind]
-            with self.open_virtualfile(family, geometry, "GMT_OUT", None) as vfile:
+            with self.open_virtualfile(
+                family, geometry, "GMT_OUT|GMT_IS_REFERENCE", None
+            ) as vfile:
                 yield vfile
 
     def inquire_virtualfile(self, vfname: str) -> int:

pygmt/datasets/load_remote_dataset.py

@@ -427,14 +427,20 @@ def _load_remote_dataset(
         )
 
     # Currently, only grids are supported. Will support images in the future.
-    kwdict = {"T": "g", "R": region}  # region can be None
+    kwdict = {"R": region}  # region can be None
+    if name in ("earth_day",):
+        kind = "image"
+        kwdict.update({"T": "i"})
+    else:
+        kind = "grid"
+        kwdict.update({"T": "g"})
     with Session() as lib:
-        with lib.virtualfile_out(kind="grid") as voutgrd:
+        with lib.virtualfile_out(kind=kind) as voutgrd:
             lib.call_module(
                 module="read",
                 args=[fname, voutgrd, *build_arg_list(kwdict)],
             )
-            grid = lib.virtualfile_to_raster(outgrid=None, vfname=voutgrd)
+            grid = lib.virtualfile_to_raster(kind=kind, outgrid=None, vfname=voutgrd)
 
     # Full path to the grid if not tiled grids.
     source = which(fname, download="a") if not resinfo.tiled else None