load_earth_relief: Add the support of data source 'synbath' (#2162)

* Add synbath option to earth_relief.py
* Add tests for Earth relief with the synbath dataset
* Update cache for synbath grids

Co-authored-by: Dongdong Tian <[email protected]>

Author: willschlitzer

pygmt/datasets/earth_relief.py

@@ -141,11 +141,15 @@ def load_earth_relief(
             f"{registration}-registered Earth relief data for "
             f"resolution '{resolution}' is not supported."
         )
-    earth_relief_sources = {"igpp": "earth_relief_", "gebco": "earth_gebco_"}
+    earth_relief_sources = {
+        "igpp": "earth_relief_",
+        "gebco": "earth_gebco_",
+        "synbath": "earth_synbath_",
+    }
     if data_source not in earth_relief_sources:
         raise GMTInvalidInput(
             f"Invalid earth relief 'data_source' {data_source}, "
-            "valid values are 'igpp' and 'gebco'."
+            "valid values are 'igpp', 'gebco', and 'synbath'."
         )
     if data_source != "igpp":
         with Session() as lib:

pygmt/helpers/testing.py

@@ -164,6 +164,7 @@ def download_test_data():
         "@earth_relief_10m_g",
         "@earth_relief_05m_p",
         "@earth_relief_05m_g",
+        "@earth_synbath_01d_g",
         # List of tiles of 03s srtm data.
         # Names like @N35E135.earth_relief_03s_g.nc is for internal use only.
         # The naming scheme may change. DO NOT USE IT IN YOUR SCRIPTS.
@@ -172,6 +173,8 @@ def download_test_data():
         "@N37W120.earth_relief_03s_g.nc",
         "@N00W090.earth_relief_03m_p.nc",
         "@N00E135.earth_relief_30s_g.nc",
+        # Earth synbath relief grids
+        "@S15W105.earth_synbath_30s_p.nc",
         # Earth seafloor age grids
         "@earth_age_01d_g",
         "@S90W180.earth_age_05m_g.nc",  # Specific grid for 05m test

pygmt/tests/test_datasets_earth_relief.py

@@ -8,7 +8,7 @@
 from pygmt.exceptions import GMTInvalidInput
 
 
-@pytest.mark.parametrize("data_source", ["igpp", "gebco"])
+@pytest.mark.parametrize("data_source", ["igpp", "gebco", "synbath"])
 def test_earth_relief_fails(data_source):
     """
     Make sure earth relief fails for invalid resolutions.
@@ -21,12 +21,14 @@ def test_earth_relief_fails(data_source):
 
 
 # Only test 01d and 30m to avoid downloading large datasets in CI
-def test_earth_relief_01d_igpp():
+@pytest.mark.parametrize("data_source", ["igpp", "synbath"])
+def test_earth_relief_01d_igpp_synbath(data_source):
     """
-    Test some properties of the earth relief 01d data with IGPP data.
+    Test some properties of the earth relief 01d data with IGPP and SYNBATH
+    data.
     """
     data = load_earth_relief(
-        resolution="01d", registration="gridline", data_source="igpp"
+        resolution="01d", registration="gridline", data_source=data_source
     )
     assert data.shape == (181, 361)
     npt.assert_allclose(data.lat, np.arange(-90, 91, 1))
@@ -112,6 +114,21 @@ def test_earth_relief_05m_with_region():
     assert data.sizes["lon"] == 481
 
 
+def test_earth_relief_30s_synbath():
+    """
+    Test some properties of the earth relief 30s data with SYNBATH data.
+    """
+    data = load_earth_relief(
+        region=[-95, -94, -1.5, -1],
+        resolution="30s",
+        registration="pixel",
+        data_source="synbath",
+    )
+    assert data.shape == (60, 120)
+    npt.assert_allclose(data.min(), -3552.5)
+    npt.assert_allclose(data.max(), -2154)
+
+
 def test_earth_relief_05m_without_region():
     """
     Test loading high-resolution earth relief without passing 'region'.