Access [0,0] from DataFrames with .at / .iat rather than .iloc

Author: JoostGevaert

src/bedrock_ge/gi/ags3.py

@@ -149,10 +149,11 @@ def ags3_to_brgi_db_mapping(
     """
     ags3_dfs = ags3_to_dfs(source, encoding)
 
-    check_ags_proj_group(ags3_dfs["PROJ"])
+    proj_df = ags3_dfs["PROJ"]
+    check_ags_proj_group(proj_df)
     ags3_project = ProjectTableMapping(
-        data=ags3_dfs["PROJ"].to_dict(orient="records")[0],
-        project_id=ags3_dfs["PROJ"]["PROJ_ID"].iloc[0],
+        data=proj_df.to_dict(orient="records")[0],
+        project_id=proj_df.at[proj_df.index[0], ["PROJ_ID"]],
         horizontal_crs=projected_crs,
         vertical_crs=vertical_crs,
     )

src/bedrock_ge/gi/ags_schemas.py

@@ -18,11 +18,14 @@ def check_ags_proj_group(ags_proj: pd.DataFrame) -> bool:
     if len(ags_proj) != 1:
         raise ValueError("The PROJ group must contain exactly one row.")
 
-    project_id = ags_proj["PROJ_ID"].iloc[0]
-    if not project_id:
-        raise ValueError(
-            'The project ID ("PROJ_ID" in the "PROJ" group) is missing from the AGS data.'
-        )
+    msg = 'The project ID ("PROJ_ID" in the "PROJ" group) is missing from the AGS data.'
+    try:
+        project_id = ags_proj.at[ags_proj.index[0], "PROJ_ID"]
+    except KeyError:
+        raise ValueError(msg)
+
+    if pd.isna(project_id) or str(project_id).strip() == "":
+        raise ValueError(msg)
 
     return True