Commented out `calc_area_change` function

[ssolson]

This function was commented out in the stressor_ulits module. There should not be commented out functions in production code. Is this function still needed?

Removed from production in #48

    def calc_area_change(self, ofilename, crs, stylefile=None):
        """Export the areas of the given file. Find a UTM of the given crs and calculate in m2."""

        cfile = ofilename.replace(".tif", ".csv")
        if os.path.isfile(cfile):
            os.remove(cfile)

        # if stylefile is not None:
        #     sdf = df_from_qml(stylefile)

        # get the basename and use the raster in the instance to get the min / max
        basename = os.path.splitext(os.path.basename(ofilename))[0]
        raster = QgsProject.instance().mapLayersByName(basename)[0]

        xmin = raster.extent().xMinimum()
        xmax = raster.extent().xMaximum()
        ymin = raster.extent().yMinimum()
        ymax = raster.extent().yMaximum()

        # using the min and max make sure the crs doesn't change across grids
        if crs==4326:
            assert find_utm_srid(xmin, ymin, crs) == find_utm_srid(
                xmax,
                ymax,
                crs,
            ), "grid spans multiple utms"
            crs_found = find_utm_srid(xmin, ymin, crs)

            # create a temporary file for reprojection
            outfile = tempfile.NamedTemporaryFile(suffix=".tif").name
            # cmd = f'gdalwarp -s_srs EPSG:{crs} -t_srs
            # EPSG:{crs_found} -r near -of GTiff {ofilename} {outfile}'
            # os.system(cmd)

            reproject_params = {
                "INPUT": ofilename,
                "SOURCE_CRS": QgsCoordinateReferenceSystem(f"EPSG:{crs}"),
                "TARGET_CRS": QgsCoordinateReferenceSystem(f"EPSG:{crs_found}"),
                "RESAMPLING": 0,
                "NODATA": None,
                "TARGET_RESOLUTION": None,
                "OPTIONS": "",
                "DATA_TYPE": 0,
                "TARGET_EXTENT": None,
                "TARGET_EXTENT_CRS": QgsCoordinateReferenceSystem(f"EPSG:{crs_found}"),
                "MULTITHREADING": False,
                "EXTRA": "",
                "OUTPUT": outfile,
            }

            # reproject to a UTM crs for meters calculation
            processing.run("gdal:warpreproject", reproject_params)

            params = {
                "BAND": 1,
                "INPUT": outfile,
                "OUTPUT_TABLE": cfile,
            }

            processing.run("native:rasterlayeruniquevaluesreport", params)
            # remove the temporary file
            os.remove(outfile)
        else:
            params = {
                "BAND": 1,
                "INPUT": ofilename,
                "OUTPUT_TABLE": cfile,
            }

            processing.run("native:rasterlayeruniquevaluesreport", params)

        df = pd.read_csv(cfile, encoding="cp1252")
        if "m2" in df.columns:
            df.rename(columns={"m2": "Area"}, inplace=True)
        elif "m²" in df.columns:
            df.rename(columns={"m²": "Area"}, inplace=True)
        elif "Unnamed: 2" in df.columns:
            df.rename(columns={"Unnamed: 2": "Area"}, inplace=True)
        df = df.groupby(by=["value"]).sum().reset_index()

        df["percentage"] = (df["Area"] / df["Area"].sum()) * 100.0

        df["value"] = df["value"].astype(float)
        # recode 0 to np.nan
        df.loc[df["value"] == 0, "value"] = float("nan")
        # sort ascending values
        df = df.sort_values(by=["value"])

        if stylefile is not None:
            df = pd.merge(df, sdf, how="left", on="value")
            df.loc[:, ["value", "label", "count", "Area", "percentage"]].to_csv(
                cfile,
                index=False,
            )
        else:
            df.loc[:, ["value", "count", "Area", "percentage"]].to_csv(
                cfile,
                na_rep="NULL",
                index=False,
                )