From 9c14b899ee1214f68e719c87bed4753af63753f1 Mon Sep 17 00:00:00 2001
From: Sirius DevOps <lance@siriusdevops.com>
Date: Thu, 27 Aug 2026 21:16:53 -0400
Subject: [PATCH] perf: simplify WFIGS perimeter geometry at query time

Ask ArcGIS for 500 features, 5-decimal precision, and ~250m offset so
fire rings are outlines instead of tens of thousands of vertices.
---
 app/live_layers.py        |  6 ++++--
 tests/test_live_layers.py | 11 +++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/app/live_layers.py b/app/live_layers.py
index 9dce0b5..aeb9736 100644
--- a/app/live_layers.py
+++ b/app/live_layers.py
@@ -597,12 +597,14 @@ async def upsert_vessel(marker: dict) -> None:
         }
 
 
-def _wfigs_params(bbox: str | None) -> dict:
+def _wfigs_params(bbox: str | None, *, offset_m: float = 250.0) -> dict:
     params = {
         "where": "1=1",
         "outSR": "4326",
         "f": "geojson",
-        "resultRecordCount": 2000,
+        "resultRecordCount": 500,
+        "maxAllowableOffset": offset_m / 111_320.0,  # metres → degrees
+        "geometryPrecision": 5,
     }
     if bbox:
         minlon, minlat, maxlon, maxlat = quantize_bbox(*parse_bbox(bbox))
diff --git a/tests/test_live_layers.py b/tests/test_live_layers.py
index bb6f183..fedf6dd 100644
--- a/tests/test_live_layers.py
+++ b/tests/test_live_layers.py
@@ -351,3 +351,14 @@ def test_slim_alert_properties_keeps_popup_fields_only():
         "wfo": "RAH",
         "source": "nws",
     }
+
+
+def test_wfigs_params_requests_simplified_geometry():
+    params = _wfigs_params("-84.5,33.8,-75.4,36.6")
+    assert "maxAllowableOffset" in params
+    assert float(params["maxAllowableOffset"]) > 0
+    assert params["geometryPrecision"] == 5
+    assert int(params["resultRecordCount"]) <= 500
+    # Envelope is the quantized cell, not the raw pan box.
+    geom = params["geometry"]
+    assert geom != "-84.5,33.8,-75.4,36.6"