diff --git a/processing/processing.go b/processing/processing.go
index 43ae76f..e80bc71 100644
--- a/processing/processing.go
+++ b/processing/processing.go
@@ -295,8 +295,11 @@ func (p *GeometryProcessor) ProcessSingle(geometry geom.Geometry) map[tms20.TMID
 	geomsAndTilesPerTileMatrix := make(map[tms20.TMID]SnapResult, len(p.tmIDs))
 	for _, tmsID := range p.tmIDs {
 		newGeometries := newGeometriesPerTileMatrix[tmsID]
-		tiles := p.detectTiles(ix, tmsID, newGeometries)
 		singleGeometry := geomhelp.GeometrySliceToGeom(newGeometries)
+		if singleGeometry == nil {
+			continue
+		}
+		tiles := p.detectTiles(ix, tmsID, newGeometries)
 		geomsAndTilesPerTileMatrix[tmsID] = SnapResult{singleGeometry, tiles}
 	}
 	return geomsAndTilesPerTileMatrix
diff --git a/processing/processing_test.go b/processing/processing_test.go
index 431d242..da6679b 100644
--- a/processing/processing_test.go
+++ b/processing/processing_test.go
@@ -346,12 +346,22 @@ func TestProcessSingle(t *testing.T) {
 				2: {Geometry: geom.MultiPolygon{polyA, polyB}, Tiles: []tile.Tile{tileA, tileB}},
 			},
 		},
+		{
+			name:   "nil geometry leaves unset results",
+			tmIDs:  []tms20.TMID{1},
+			config: Config{EncodeTiles: true, UseLineTrace: false},
+			snapOutput: map[tms20.TMID][]geom.Geometry{
+				1: {},
+			},
+			detectTilesResult: map[tms20.TMID][]tile.Tile{},
+			want:              map[tms20.TMID]SnapResult{},
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			// This counts how often "tileDetect" has been called
-			numDetect := len(tt.tmIDs)
+			numDetect := len(tt.want)
 
 			processor := NewGeometryProcessor(tt.tmIDs, tt.config, createMockSnapFunc(tt.snapOutput), createMockIndexFactory(&numDetect, tt.insertErr, tt.detectTilesResult))