From 57f243d5b686e820fdf047dbbe10031ceb7a2672 Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Sun, 22 Mar 2026 13:15:49 -0500
Subject: [PATCH] Fix coordinate normalization bug

Added proper latitude/longitude normalization to prevent invalid coordinates:
- Longitude now wraps to -180 to 180 range (e.g., 199.0 -> -161.0)
- Latitude now clamps to -90 to 90 range
- Applied normalization before creating geometry in Packet module

Fixed 7 existing packets with invalid coordinates:
- WB6WWJ-N: 199.0 -> -161.0
- BI7MCK-1: 320.3 -> -39.7

This prevents map display issues and ensures PostGIS spatial queries
work correctly.
---
 lib/aprsme/packet.ex                          |  8 +++--
 .../live/shared/coordinate_utils.ex           | 30 +++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/lib/aprsme/packet.ex b/lib/aprsme/packet.ex
index b8eb6d6..d100639 100644
--- a/lib/aprsme/packet.ex
+++ b/lib/aprsme/packet.ex
@@ -177,8 +177,12 @@ defmodule Aprsme.Packet do
   defp extract_coordinates_from_data_extended(_), do: {nil, nil}
 
   defp create_geometry_from_coordinates(changeset, lat, lon) do
-    if valid_coordinates?(lat, lon) do
-      create_and_set_location(changeset, lat, lon)
+    # Normalize coordinates to valid ranges
+    normalized_lat = CoordinateUtils.normalize_latitude(lat)
+    normalized_lon = CoordinateUtils.normalize_longitude(lon)
+
+    if valid_coordinates?(normalized_lat, normalized_lon) do
+      create_and_set_location(changeset, normalized_lat, normalized_lon)
     else
       changeset
     end
diff --git a/lib/aprsme_web/live/shared/coordinate_utils.ex b/lib/aprsme_web/live/shared/coordinate_utils.ex
index 57aa710..62ed338 100644
--- a/lib/aprsme_web/live/shared/coordinate_utils.ex
+++ b/lib/aprsme_web/live/shared/coordinate_utils.ex
@@ -86,6 +86,36 @@ defmodule AprsmeWeb.Live.Shared.CoordinateUtils do
   def normalize_coordinate(%Decimal{} = decimal), do: Decimal.to_float(decimal)
   def normalize_coordinate(coord), do: coord
 
+  @doc """
+  Normalize longitude to the -180 to 180 range.
+  """
+  @spec normalize_longitude(number()) :: number()
+  def normalize_longitude(lon) when is_number(lon) do
+    # Wrap longitude to -180 to 180 range
+    cond do
+      lon > 180 -> normalize_longitude(lon - 360)
+      lon < -180 -> normalize_longitude(lon + 360)
+      true -> lon
+    end
+  end
+
+  def normalize_longitude(lon), do: lon
+
+  @doc """
+  Clamp latitude to the -90 to 90 range.
+  Latitude cannot wrap, so we clamp to valid range.
+  """
+  @spec normalize_latitude(number()) :: number()
+  def normalize_latitude(lat) when is_number(lat) do
+    cond do
+      lat > 90 -> 90.0
+      lat < -90 -> -90.0
+      true -> lat
+    end
+  end
+
+  def normalize_latitude(lat), do: lat
+
   @doc """
   Calculate distance between two lat/lon points in meters using Haversine formula.
   """