diff --git a/Development/server/helpers/gridline_util.js b/Development/server/helpers/gridline_util.js
index e9971b0..f9669a7 100644
--- a/Development/server/helpers/gridline_util.js
+++ b/Development/server/helpers/gridline_util.js
@@ -99,7 +99,15 @@ async function getLinesLatLng(job, sprayIds, halfSwathOffset = true, x, y, headi
   // Convert line buffers to xcl zones then also include them within the next process
   if (bufs && bufs.length) {
     for (let i = 0; i < bufs.length; i++) {
-      const polyCoors = bufUtil.lineBuffer(bufs[i].geometry.coordinates, utils.toMeter(bufs[i].properties.width, job.measureUnit));
+      const geoType = bufs[i].geometry.type;
+      let polyCoors;
+      if (geoType === 'Polygon') {
+        // Edge buffers and feature buffers are already polygons — use the outer ring directly
+        polyCoors = bufs[i].geometry.coordinates[0];
+      } else {
+        // Segment/corridor buffers are LineStrings — expand to polygon using corridor width
+        polyCoors = bufUtil.lineBuffer(bufs[i].geometry.coordinates, utils.toMeter(bufs[i].properties.width, job.measureUnit));
+      }
       if (!utils.isEmptyArray(polyCoors)) {
         xclZones.push(jobUtil.createXclArea({ name: `XCL${i + 1}`, coors: polyCoors }));
       }