{
  "claims": [
    {
      "claim": {
        "claim_id": "claim-yost-fern-route-profile",
        "evidence_ids": [
          "evidence-yost-fern-route-profile"
        ],
        "predicate": "route_profile",
        "spatial_scope_ids": [
          "scope-trailhead-yost-fern"
        ],
        "subject_id": "trailhead-yost-fern",
        "temporal_scope": null,
        "value": {
          "fern_beyond_fork_miles": 0.7,
          "fern_total_one_way_miles": 2.2,
          "shared_distance_to_fork_miles": 1.5,
          "yost_beyond_fork_miles": 2.3,
          "yost_total_one_way_miles": 3.8
        }
      },
      "evidence": [
        {
          "claim_id": "claim-yost-fern-route-profile",
          "evidence_id": "evidence-yost-fern-route-profile",
          "notes": "",
          "observation_id": "observation-usfs-mono-basin-day-hikes-20260923",
          "stance": "supports"
        }
      ],
      "observations": [
        {
          "artifact_refs": [],
          "content": "The Mono Basin day-hike guide maps Parker Lake, Yost and Fern Lakes, and Lundy Canyon. Parker Lake is 1.8 miles one way. The Yost/Fern route splits 1.5 miles from its trailhead; Fern Lake is another 0.7 mile and Yost Lake another 2.3 miles. Lundy Canyon reaches 20 Lakes Basin in 5.4 miles one way; its bottom two-thirds are easier and its upper third climbs steep switchbacks. The guide publishes road and parking directions for each trailhead.",
          "observation_id": "observation-usfs-mono-basin-day-hikes-20260923",
          "observed_at": null,
          "observer": "",
          "retrieved_at": "2026-09-23T23:00:00+00:00",
          "source_id": "source-usfs-mono-basin-day-hikes"
        }
      ],
      "sources": [
        {
          "locator": "https://www.fs.usda.gov/media/123306",
          "publisher": "USDA Forest Service",
          "source_id": "source-usfs-mono-basin-day-hikes"
        }
      ]
    }
  ],
  "entities": [
    {
      "entity_id": "route-fern-lake-june",
      "kind": "route",
      "name": "Fern Lake Trail"
    },
    {
      "entity_id": "route-yost-lake",
      "kind": "route",
      "name": "Yost Lake Trail"
    },
    {
      "entity_id": "trailhead-yost-fern",
      "kind": "trailhead",
      "name": "Yost and Fern Lakes Trailhead"
    }
  ],
  "history": [
    {
      "action": "ADD",
      "change_set_id": "wp-20260924-june-lake-yost-fern-route-depth",
      "evidence_refs": [],
      "knowledge_gap_refs": [],
      "path": "canonical/v0/gaps/gap-yost-fern-dataset-distance-disagreement.json",
      "reason": "Add shared-corridor and branch topology for the Yost and Fern Lake alternatives.",
      "record_id": "gap-yost-fern-dataset-distance-disagreement",
      "record_type": "gap",
      "summary": "Add a shared Yost/Fern route corridor, evidenced destination branches, official published hike distances, map geometry, and an explicit source-distance disagreement."
    }
  ],
  "navigation": {
    "next_id": "gap-yost-fern-trailhead-operations",
    "position": 298,
    "previous_id": "gap-yosemite-wilderness-entry-physical-starts",
    "total": 299
  },
  "observations": [
    {
      "artifact_refs": [],
      "content": "The Mono Basin day-hike guide maps Parker Lake, Yost and Fern Lakes, and Lundy Canyon. Parker Lake is 1.8 miles one way. The Yost/Fern route splits 1.5 miles from its trailhead; Fern Lake is another 0.7 mile and Yost Lake another 2.3 miles. Lundy Canyon reaches 20 Lakes Basin in 5.4 miles one way; its bottom two-thirds are easier and its upper third climbs steep switchbacks. The guide publishes road and parking directions for each trailhead.",
      "observation_id": "observation-usfs-mono-basin-day-hikes-20260923",
      "observed_at": null,
      "observer": "",
      "retrieved_at": "2026-09-23T23:00:00+00:00",
      "source_id": "source-usfs-mono-basin-day-hikes"
    }
  ],
  "record": {
    "gap_id": "gap-yost-fern-dataset-distance-disagreement",
    "question": "Why do the retained National Digital Trails length fields disagree with the USFS Mono Basin hiking-guide distances for the Yost/Fern shared corridor and Yost branch?",
    "reason": "The route geometry is connected and useful for map context, but Wayproof does not replace the official hiking-guide distances or claim survey-grade geometry from the dataset fields.",
    "related_ids": [
      "route-yost-lake",
      "route-fern-lake-june",
      "claim-yost-fern-route-profile"
    ]
  },
  "record_type": "gap",
  "related_records": [
    {
      "record": {
        "entity_id": "route-yost-lake",
        "kind": "route",
        "name": "Yost Lake Trail"
      },
      "record_id": "route-yost-lake",
      "record_type": "entity"
    },
    {
      "record": {
        "entity_id": "route-fern-lake-june",
        "kind": "route",
        "name": "Fern Lake Trail"
      },
      "record_id": "route-fern-lake-june",
      "record_type": "entity"
    },
    {
      "record": {
        "claim_id": "claim-yost-fern-route-profile",
        "evidence_ids": [
          "evidence-yost-fern-route-profile"
        ],
        "predicate": "route_profile",
        "spatial_scope_ids": [
          "scope-trailhead-yost-fern"
        ],
        "subject_id": "trailhead-yost-fern",
        "temporal_scope": null,
        "value": {
          "fern_beyond_fork_miles": 0.7,
          "fern_total_one_way_miles": 2.2,
          "shared_distance_to_fork_miles": 1.5,
          "yost_beyond_fork_miles": 2.3,
          "yost_total_one_way_miles": 3.8
        }
      },
      "record_id": "claim-yost-fern-route-profile",
      "record_type": "claim"
    }
  ],
  "sources": [
    {
      "locator": "https://www.fs.usda.gov/media/123306",
      "publisher": "USDA Forest Service",
      "source_id": "source-usfs-mono-basin-day-hikes"
    }
  ]
}