Add zoom_adjust parameter to pygmt.datasets.load_tile_map and Figure.tilemap

pygmt/datasets/tile_map.py

@@ -2,6 +2,9 @@
 Function to load raster tile maps from XYZ tile providers, and load as
 :class:`xarray.DataArray`.
 """
+from __future__ import annotations
+
+from packaging.version import Version
 
 try:
     import contextily
@@ -16,7 +19,15 @@
 __doctest_requires__ = {("load_tile_map"): ["contextily"]}
 
 
-def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_retries=2):
+def load_tile_map(
+    region,
+    zoom="auto",
+    source=None,
+    lonlat=True,
+    wait=0,
+    max_retries=2,
+    zoom_adjust: int | None = None,
+):
     """
     Load a georeferenced raster tile map from XYZ tile providers.
 
@@ -40,9 +51,9 @@ def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_ret
         ``"auto"`` to automatically determine the zoom level based on the
         bounding box region extent].
 
-        **Note**: The maximum possible zoom level may be smaller than ``22``,
-        and depends on what is supported by the chosen web tile provider
-        source.
+        .. note::
+           The maximum possible zoom level may be smaller than ``22``, and depends on
+           what is supported by the chosen web tile provider source.
 
     source : xyzservices.TileProvider or str
         Optional. The tile source: web tile provider or path to a local file.
@@ -62,8 +73,8 @@ def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_ret
           basemap. See
           :doc:`contextily:working_with_local_files`.
 
-        IMPORTANT: Tiles are assumed to be in the Spherical Mercator projection
-        (EPSG:3857).
+        .. important::
+           Tiles are assumed to be in the Spherical Mercator projection (EPSG:3857).
 
     lonlat : bool
         Optional. If ``False``, coordinates in ``region`` are assumed to be
@@ -79,6 +90,13 @@ def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_ret
         will stop trying to fetch more tiles from a rate-limited API [Default
         is ``2``].
 
+    zoom_adjust
+        The amount to adjust a chosen zoom level if it is chosen automatically. Values
+        outside of -1 to 1 are not recommended as they can lead to slow execution.
+
+        .. note::
+           The ``zoom_adjust`` parameter requires ``contextily>=1.5.0``.
+
     Returns
     -------
     raster : xarray.DataArray
@@ -117,6 +135,15 @@ def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_ret
             "to install the package."
         )
 
+    contextily_kwargs = {}
+    if zoom_adjust is not None:
+        contextily_kwargs["zoom_adjust"] = zoom_adjust
+        if Version(contextily.__version__) < Version("1.5.0"):
+            raise TypeError(
+                "The `zoom_adjust` parameter requires `contextily>=1.5.0` to work. "
+                "Please upgrade contextily, or manually set the `zoom` level instead."
+            )
+
     west, east, south, north = region
     image, extent = contextily.bounds2img(
         w=west,
@@ -128,6 +155,7 @@ def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_ret
         ll=lonlat,
         wait=wait,
         max_retries=max_retries,
+        **contextily_kwargs,
     )
 
     # Turn RGBA img from channel-last to channel-first and get 3-band RGB only
@@ -139,7 +167,7 @@ def load_tile_map(region, zoom="auto", source=None, lonlat=True, wait=0, max_ret
     dataarray = xr.DataArray(
         data=rgb_image,
         coords={
-            "band": np.uint8([0, 1, 2]),  # Red, Green, Blue
+            "band": np.array(object=[0, 1, 2], dtype=np.uint8),  # Red, Green, Blue
             "y": np.linspace(start=top, stop=bottom, num=rgb_image.shape[1]),
             "x": np.linspace(start=left, stop=right, num=rgb_image.shape[2]),
         },

pygmt/src/tilemap.py

@@ -1,6 +1,8 @@
 """
 tilemap - Plot XYZ tile maps.
 """
+from __future__ import annotations
+
 from pygmt.clib import Session
 from pygmt.datasets.tile_map import load_tile_map
 from pygmt.helpers import build_arg_string, fmt_docstring, kwargs_to_strings, use_alias
@@ -30,7 +32,15 @@
 )
 @kwargs_to_strings(c="sequence_comma", p="sequence")  # R="sequence",
 def tilemap(
-    self, region, zoom="auto", source=None, lonlat=True, wait=0, max_retries=2, **kwargs
+    self,
+    region,
+    zoom="auto",
+    source=None,
+    lonlat=True,
+    wait=0,
+    max_retries=2,
+    zoom_adjust: int | None = None,
+    **kwargs,
 ):
     r"""
     Plots an XYZ tile map.
@@ -64,9 +74,9 @@ def tilemap(
         ``"auto"`` to automatically determine the zoom level based on the
         bounding box region extent].
 
-        **Note**: The maximum possible zoom level may be smaller than ``22``,
-        and depends on what is supported by the chosen web tile provider
-        source.
+        .. note::
+           The maximum possible zoom level may be smaller than ``22``, and depends on
+           what is supported by the chosen web tile provider source.
 
     source : xyzservices.TileProvider or str
         Optional. The tile source: web tile provider or path to a local file.
@@ -86,8 +96,8 @@ def tilemap(
           basemap. See
           :doc:`contextily:working_with_local_files`.
 
-        IMPORTANT: Tiles are assumed to be in the Spherical Mercator projection
-        (EPSG:3857).
+        .. important::
+           Tiles are assumed to be in the Spherical Mercator projection (EPSG:3857).
 
     lonlat : bool
         Optional. If ``False``, coordinates in ``region`` are assumed to be
@@ -103,6 +113,13 @@ def tilemap(
         will stop trying to fetch more tiles from a rate-limited API [Default
         is ``2``].
 
+    zoom_adjust
+        The amount to adjust a chosen zoom level if it is chosen automatically. Values
+        outside of -1 to 1 are not recommended as they can lead to slow execution.
+
+        .. note::
+           The ``zoom_adjust`` parameter requires ``contextily>=1.5.0``.
+
     kwargs : dict
         Extra keyword arguments to pass to :meth:`pygmt.Figure.grdimage`.
 
@@ -131,6 +148,7 @@ def tilemap(
         lonlat=lonlat,
         wait=wait,
         max_retries=max_retries,
+        zoom_adjust=zoom_adjust,
     )
 
     # Reproject raster from Spherical Mercator (EPSG:3857) to