From 47b1615a8c2675cbfa2785cffd817cc01e98e9e9 Mon Sep 17 00:00:00 2001
From: Yannick Brosseau <yannick.brosseau@gmail.com>
Date: Thu, 19 Oct 2023 15:25:03 -0400
Subject: [PATCH] Add a comment to explain why we do not directly call
 EuclideanGeoFilter in the OSRMGeoFilter, in the first filter pass

---
 src/osrmgeofilter.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/osrmgeofilter.cpp b/src/osrmgeofilter.cpp
index a312530..94bcca1 100644
--- a/src/osrmgeofilter.cpp
+++ b/src/osrmgeofilter.cpp
@@ -31,6 +31,9 @@ namespace TrRouting {
 
     std::string queryString = "/table/v1/" + mode + "/" + std::to_string(point.longitude) + "," + std::to_string(point.latitude);
 
+    // We first filter the nodes with euclidean distance using the common distance calculation
+    // to only send a subset of nodes to OSRM. We do not reuse the EuclideanGeoFilter directly, since
+    // we process the data differently here. (We directly compute the OSRM query.)
     for (auto &&[uuid,node] : nodes)
     {
       distanceMetersSquared = calculateNodeDistanceSquared(node.point.get(), point, lengthOfOneDegree);