Save ReferencePoint into file in timeseries/ folder (#374)

* Save `ReferencePoint` into file in `timeseries/` folder

* only compute the reference if needed

* fix cor vrt name typo

* better logging of reference point

src/dolphin/timeseries.py

@@ -84,18 +84,19 @@ def run(
     """
     condition_func = argmax_index if condition == CallFunc.MAX else argmin_index
 
-    Path(output_dir).mkdir(exist_ok=True, parents=True)
+    def _get_reference():
+        # First we find the reference point for the unwrapped interferograms
+        if reference_point == (-1, -1):
+            return select_reference_point(
+                condition_file=condition_file,
+                output_dir=Path(output_dir),
+                condition_func=condition_func,
+                ccl_file_list=conncomp_paths,
+            )
+        else:
+            return ReferencePoint(row=reference_point[0], col=reference_point[1])
 
-    # First we find the reference point for the unwrapped interferograms
-    if reference_point == (-1, -1):
-        reference = select_reference_point(
-            condition_file=condition_file,
-            output_dir=Path(output_dir),
-            condition_func=condition_func,
-            ccl_file_list=conncomp_paths,
-        )
-    else:
-        reference = ReferencePoint(row=reference_point[0], col=reference_point[1])
+    Path(output_dir).mkdir(exist_ok=True, parents=True)
 
     ifg_date_pairs = [get_dates(f) for f in unwrapped_paths]
     sar_dates = sorted(set(utils.flatten(ifg_date_pairs)))
@@ -110,7 +111,7 @@ def run(
         logger.info("Inverting network of %s unwrapped ifgs", len(unwrapped_paths))
         inverted_phase_paths = invert_unw_network(
             unw_file_list=unwrapped_paths,
-            reference=reference,
+            reference=_get_reference(),
             output_dir=output_dir,
             num_threads=num_threads,
         )
@@ -144,7 +145,7 @@ def run(
         create_velocity(
             unw_file_list=inverted_phase_paths,
             output_file=velocity_file,
-            reference=reference,
+            reference=_get_reference(),
             cor_file_list=cor_file_list,
             cor_threshold=correlation_threshold,
             num_threads=num_threads,
@@ -711,7 +712,7 @@ def invert_unw_network(
     unw_reader = io.VRTStack(
         file_list=unw_file_list, outfile=out_vrt_name, skip_size_check=True
     )
-    cor_vrt_name = Path(output_dir) / "unw_network.vrt"
+    cor_vrt_name = Path(output_dir) / "cor_network.vrt"
 
     # Get the reference point data
     ref_row, ref_col = reference
@@ -835,6 +836,12 @@ def select_reference_point(
         component label files
 
     """
+    output_file = output_dir / "reference_point.txt"
+    if output_file.exists():
+        ref_point = _read_reference_point(output_file=output_file)
+        logger.info(f"Read {ref_point!r} from existing {output_file}")
+        return ref_point
+
     logger.info("Selecting reference point")
     condition_file_values = io.load_gdal(condition_file, masked=True)
 
@@ -859,7 +866,18 @@ def select_reference_point(
     ref_row, ref_col = condition_func(condition_file_values)
 
     # Cast to `int` to avoid having `np.int64` types
-    return ReferencePoint(int(ref_row), int(ref_col))
+    ref_point = ReferencePoint(int(ref_row), int(ref_col))
+    logger.info(f"Saving {ref_point!r} to from existing {output_file}")
+    _write_reference_point(output_file=output_file, ref_point=ref_point)
+    return ref_point
+
+
+def _write_reference_point(output_file: Path, ref_point: ReferencePoint) -> None:
+    output_file.write_text(",".join(list(map(str, ref_point))))
+
+
+def _read_reference_point(output_file: Path):
+    return ReferencePoint(*[int(n) for n in output_file.read_text().split(",")])
 
 
 def _get_largest_conncomp_mask(
@@ -891,7 +909,6 @@ def intersect_conncomp(arr: np.ma.MaskedArray, axis: int) -> np.ndarray:
             read_masked=True,
         )
 
-    logger.info("Selecting reference point")
     conncomp_intersection = io.load_gdal(conncomp_intersection_file, masked=True)
 
     # Find the largest conncomp region in the intersection