Incorrect water flow direction.

map-issues-bot commented

2026-08-05 09:54:00 +00:00

Collaborator

This particular river segment should be draining into the river polygon NW from it. But instead it is importance=1 and everything south of it is higher importance. Am I guessing right and our strahler computation only checks endpoints of a line which means that since this river connects to the river polygon at a mid point of its linestring it can't be detected to drain into the river polygon and that inverses the logic?

Location: z20 / 65.55624 / -17.69235
Feature: waterways — country=is, importance=1, water_class=watercourse

{
 "features": [
  {
   "geometry": {
    "type": "LineString",
    "coordinates": [
     [
      -17.692086696624756,
      65.55629561092121
     ],
     [
      -17.692407136783004,
      65.5562810435411
     ],
     [
      -17.692225500941277,
      65.55617792706752
     ]
    ]
   },
   "properties": {
    "_layer": "waterways",
    "_sourceLayer": "waterways",
    "country": "is",
    "importance": 1,
    "water_class": "watercourse"
   },
   "type": "Feature"
  }
 ],
 "properties": {
  "lat": 65.556242,
  "lng": -17.692352,
  "map": "is",
  "zoom": 19.58
 },
 "type": "FeatureCollection"
}

This particular river segment should be draining into the river polygon NW from it. But instead it is importance=1 and everything south of it is higher importance. Am I guessing right and our strahler computation only checks endpoints of a line which means that since this river connects to the river polygon at a mid point of its linestring it can't be detected to drain into the river polygon and that inverses the logic? --- **Location:** [z20 / 65.55624 / -17.69235](https://experiments.blahonga.org/?map=is#19.58/65.5562419/-17.6923519) **Feature:** `waterways` — country=is, importance=1, water_class=watercourse ```map-report { "features": [ { "geometry": { "type": "LineString", "coordinates": [ [ -17.692086696624756, 65.55629561092121 ], [ -17.692407136783004, 65.5562810435411 ], [ -17.692225500941277, 65.55617792706752 ] ] }, "properties": { "_layer": "waterways", "_sourceLayer": "waterways", "country": "is", "importance": 1, "water_class": "watercourse" }, "type": "Feature" } ], "properties": { "lat": 65.556242, "lng": -17.692352, "map": "is", "zoom": 19.58 }, "type": "FeatureCollection" } ```

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2026-08-05 09:54:00 +00:00