fix: replace pygmt gridding with simple set_index for plotting

src/invert4geom/plotting.py

@@ -245,8 +245,6 @@ def grid_inversion_results(
     prisms_ds: xr.Dataset,
     grav_results: pd.DataFrame,
     region: tuple[float, float, float, float],
-    spacing: float,
-    registration: str,
 ) -> tuple[list[xr.DataArray], list[xr.DataArray], list[xr.DataArray]]:
     """
     create grids from the various data variables of the supplied gravity dataframe and
@@ -266,10 +264,6 @@ def grid_inversion_results(
         resulting dataframe of gravity data from the inversion
     region : tuple[float, float, float, float]
         region to use for gridding in format (xmin, xmax, ymin, ymax)
-    spacing : float
-        grid spacing in meters
-    registration : str
-       grid registration type, either "g" for gridline or "p" for pixel
 
     Returns
     -------
@@ -278,13 +272,7 @@ def grid_inversion_results(
     """
     misfit_grids = []
     for m in misfits:
-        grid = pygmt.xyz2grd(
-            data=grav_results[["easting", "northing", m]],
-            region=region,
-            spacing=spacing,
-            registration=registration,
-            verbose="q",
-        )
+        grid = grav_results.set_index(["northing", "easting"]).to_xarray()[m]
         misfit_grids.append(grid)
 
     topo_grids = []
@@ -414,8 +402,6 @@ def plot_inversion_topo_results(
 def plot_inversion_grav_results(
     grav_results: pd.DataFrame,
     region: tuple[float, float, float, float],
-    spacing: float,
-    registration: str,
     iterations: list[int],
 ) -> None:
     """
@@ -427,37 +413,22 @@ def plot_inversion_grav_results(
         resulting dataframe of gravity data from the inversion
     region : tuple[float, float, float, float]
         region to use for gridding in format (xmin, xmax, ymin, ymax)
-    spacing : float
-        grid spacing in meters
-    registration : str
-        grid registration type, either "g" for gridline or "p" for pixel
     iterations : list[int]
         list of all the iteration numbers
     """
-    initial_misfit = pygmt.xyz2grd(
-        data=grav_results[["easting", "northing", "iter_1_initial_misfit"]],
-        region=region,
-        spacing=spacing,
-        registration=registration,
-        verbose="q",
-    )
 
-    final_misfit = pygmt.xyz2grd(
-        data=grav_results[
-            ["easting", "northing", f"iter_{max(iterations)}_final_misfit"]
-        ],
-        region=region,
-        spacing=spacing,
-        registration=registration,
-        verbose="q",
-    )
+    grid = grav_results.set_index(["northing", "easting"]).to_xarray()
+
+    initial_misfit = grid["iter_1_initial_misfit"]
+    final_misfit = grid[f"iter_{max(iterations)}_final_misfit"]
 
     initial_rmse = utils.rmse(grav_results["iter_1_initial_misfit"])
     final_rmse = utils.rmse(grav_results[f"iter_{max(iterations)}_final_misfit"])
 
     _ = polar_utils.grd_compare(
         initial_misfit,
         final_misfit,
+        region=region,
         plot=True,
         grid1_name=f"Initial misfit: RMSE={round(initial_rmse, 2)} mGal",
         grid2_name=f"Final misfit: RMSE={round(final_rmse, 2)} mGal",
@@ -682,8 +653,6 @@ def plot_inversion_results(
     topo_results: pd.DataFrame | str,
     parameters: dict[str, typing.Any] | str,
     grav_region: tuple[float, float, float, float] | None,
-    grav_spacing: float,
-    registration: str = "g",
     iters_to_plot: int | None = None,
     plot_iter_results: bool = True,
     plot_topo_results: bool = True,
@@ -703,10 +672,6 @@ def plot_inversion_results(
         inversion parameters dictionary or filename
     grav_region : tuple[float, float, float, float] | None
         region to use for gridding in format (xmin, xmax, ymin, ymax), by default None
-    grav_spacing : float
-        grid spacing in meters
-    registration : str, optional
-        grid registration type, either "g" for gridline or "p" for pixel, by default "g"
     iters_to_plot : int | None, optional
         number of iterations to plot, including the first and last, by default None
     plot_iter_results : bool, optional
@@ -774,8 +739,6 @@ def plot_inversion_results(
         prisms_ds,
         grav_results,
         grav_region,
-        grav_spacing,
-        registration,
     )
 
     if plot_iter_results is True:
@@ -800,8 +763,6 @@ def plot_inversion_results(
         plot_inversion_grav_results(
             grav_results,
             grav_region,
-            grav_spacing,
-            registration,
             iterations,
         )