From 99d60acd9c337dc7503892e8232d01f6ee8042b8 Mon Sep 17 00:00:00 2001
From: Renato Durrer <renato.durrer@visium.ch>
Date: Fri, 24 May 2024 13:26:17 +0200
Subject: [PATCH] Check for validation if coordinates are valid.

---
 .../util/coordinate_extraction.py             | 54 ++++++++++++++++---
 1 file changed, 46 insertions(+), 8 deletions(-)

diff --git a/src/stratigraphy/util/coordinate_extraction.py b/src/stratigraphy/util/coordinate_extraction.py
index 45a1da8f..983aaf1c 100644
--- a/src/stratigraphy/util/coordinate_extraction.py
+++ b/src/stratigraphy/util/coordinate_extraction.py
@@ -53,6 +53,10 @@ def __repr__(self):  # noqa: D105
     def to_json(self):
         pass
 
+    @abc.abstractmethod
+    def is_valid(self):
+        pass
+
     @staticmethod
     def from_json(input: dict):
         east = input["E"]
@@ -82,6 +86,15 @@ def to_json(self):
             "N": self.north.coordinate_value,
         }
 
+    def is_valid(self):
+        """Reference: https://de.wikipedia.org/wiki/Schweizer_Landeskoordinaten#Beispielkoordinaten."""
+        return (
+            self.east.coordinate_value > 2324800
+            and self.east.coordinate_value < 2847500
+            and self.north.coordinate_value > 1074000
+            and self.north.coordinate_value < 1302000
+        )
+
 
 @dataclass
 class LV03Coordinate(Coordinate):
@@ -99,6 +112,18 @@ def to_json(self):
             "N": self.north.coordinate_value,
         }
 
+    def is_valid(self):
+        """Reference: https://de.wikipedia.org/wiki/Schweizer_Landeskoordinaten#Beispielkoordinaten.
+
+        To account for uncertainties in the conversion of LV03 to LV95, we allow a margin of 2.
+        """
+        return (
+            self.east.coordinate_value > 324798
+            and self.east.coordinate_value < 847502
+            and self.north.coordinate_value > 73998
+            and self.north.coordinate_value < 302002
+        )
+
 
 class CoordinateExtractor:
     """Extracts coordinates from a PDF document."""
@@ -202,7 +227,7 @@ def get_coordinates_text(text: str) -> list:
             list: A list of matched coordinates.
         """
         return regex.findall(
-            r"[XY]?[=:\s]{0,2}" + COORDINATE_ENTRY_REGEX + r".*[XY]?[=:\s]{0,2}" + COORDINATE_ENTRY_REGEX,
+            r"[XY]?[=:\s]{0,2}" + COORDINATE_ENTRY_REGEX + r".{0,4}[XY]?[=:\s]{0,2}" + COORDINATE_ENTRY_REGEX,
             text,
         )
 
@@ -224,9 +249,13 @@ def extract_coordinates(self) -> list:
 
         # try to get the text by including X and Y
         try:
-            y_coordinate_string = regex.findall(r"Y[=:\s]{0,2}" + COORDINATE_ENTRY_REGEX, text)
-            x_coordinate_string = regex.findall(r"X[=:\s]{0,2}" + COORDINATE_ENTRY_REGEX, text)
-            coordinate_string = y_coordinate_string[0] + " / " + x_coordinate_string[0]
+            y_coordinate_string = regex.findall(r"Y[=:\s]{0,3}" + COORDINATE_ENTRY_REGEX, text)
+            x_coordinate_string = regex.findall(r"X[=:\s]{0,3}" + COORDINATE_ENTRY_REGEX, text)
+            coordinate_string = (
+                y_coordinate_string[0].replace(" ", "") + " / " + x_coordinate_string[0].replace(" ", "")
+            )
+            # if we have a 'Y' and 'X' coordinate, we can allow for some whitespace in between the numbers.
+            # In some older borehole profile the OCR may recognize whitespace between two digits.
         except IndexError:  # no coordinates found
             try:
                 # get the substring that contains the coordinate information
@@ -249,7 +278,7 @@ def extract_coordinates(self) -> list:
                 # leading 2 or 1.
                 east1 = regex.sub(r"\D", "", east1)
                 north1 = regex.sub(r"\D", "", north1)
-                return LV95Coordinate(
+                coordinate = LV95Coordinate(
                     CoordinateEntry.create_from_string(east1, east2),
                     CoordinateEntry.create_from_string(north1, north2),
                 )
@@ -259,24 +288,33 @@ def extract_coordinates(self) -> list:
                 # in these case we just truncate to the required 3 digits
                 east1 = east1[-3:]
                 north1 = north1[-3:]
-                return LV03Coordinate(
+                coordinate = LV03Coordinate(
                     CoordinateEntry.create_from_string(east1, east2),
                     CoordinateEntry.create_from_string(north1, north2),
                 )
+            if coordinate.is_valid():
+                return coordinate
+            else:
+                return None
 
         else:
             try:
                 matches = regex.findall(r"[12]?\d{6}", coordinate_string)
                 if len(matches[0]) == 6:  # we expect matches[0] and matches[1] to have the same length
-                    return LV03Coordinate(
+                    coordinate = LV03Coordinate(
                         CoordinateEntry.create_from_string(matches[0]), CoordinateEntry.create_from_string(matches[1])
                     )
 
                 if len(matches[0]) == 7:
-                    return LV95Coordinate(
+                    coordinate = LV95Coordinate(
                         CoordinateEntry.create_from_string(matches[0]), CoordinateEntry.create_from_string(matches[1])
                     )
 
+                if isinstance(coordinate, Coordinate) and coordinate.is_valid():
+                    return coordinate
+
+                return None
+
             except IndexError:
                 logger.warning(f"Could not extract coordinates from: {coordinate_string}")
                 return None