Ensure that plot is clipped to bounding box region when no_clip is False

Pass the region to the grdimage call so that the plot extent is the same as the bounding box region. Set `no_clip=True` to prevent the clipping from happening (i.e., the plot will extend out from the region of interest). Added a unit test checking results for both no_clip True/False, and updated some previous baseline images that have changed slightly.

Author: weiji14

pygmt/src/tilemap.py

@@ -142,6 +142,11 @@ def tilemap(
         raster = raster.rio.reproject(dst_crs="OGC:CRS84")
         raster.gmt.gtype = 1  # set to geographic type
 
+    # Only set region if no_clip is False, so that plot is clipped to exact
+    # bounding box region
+    if not kwargs.get("N"):
+        kwargs["R"] = "/".join(str(coordinate) for coordinate in region)
+
     with GMTTempFile(suffix=".tif") as tmpfile:
         raster.rio.to_raster(raster_path=tmpfile.name)
         with Session() as lib:

pygmt/tests/baseline/test_tilemap_no_clip_False.png.dvc

@@ -0,0 +1,4 @@
+outs:
+- md5: 9317080021b0ce6f3b9ea6d17feece00
+  size: 23275
+  path: test_tilemap_no_clip_False.png

pygmt/tests/baseline/test_tilemap_no_clip_True.png.dvc

@@ -0,0 +1,4 @@
+outs:
+- md5: 83e6119b2351f9d472ca7e3cc45388c3
+  size: 60984
+  path: test_tilemap_no_clip_True.png

pygmt/tests/baseline/test_tilemap_ogc_wgs84.png.dvc

@@ -1,4 +1,4 @@
 outs:
-- md5: cc40d807da1218cd440dd8655f5f57fb
-  size: 56875
+- md5: 3de0555d86aca49b92425c8d5272a934
+  size: 59286
   path: test_tilemap_ogc_wgs84.png

pygmt/tests/baseline/test_tilemap_web_mercator.png.dvc

@@ -1,4 +1,4 @@
 outs:
-- md5: ea1fc9d829e8534aed7dac825ea0ddff
-  size: 123201
+- md5: a76d9a9a1890d6b1345305eaea598bc3
+  size: 122195
   path: test_tilemap_web_mercator.png

pygmt/tests/test_tilemap.py

@@ -38,3 +38,21 @@ def test_tilemap_ogc_wgs84():
         verbose=True,
     )
     return fig
+
+
+@pytest.mark.mpl_image_compare
+@pytest.mark.parametrize("no_clip", [False, True])
+def test_tilemap_no_clip(no_clip):
+    """
+    Create a tilemap plot clipped to the Southern Hemisphere when no_clip is
+    False, but for the whole globe when no_clip is True.
+    """
+    fig = Figure()
+    fig.tilemap(
+        region=[-180.0, 180.0, -90, 0.6886],
+        zoom=0,
+        frame="afg",
+        projection="H180/5c",
+        no_clip=no_clip,
+    )
+    return fig