{
 "title_en": "Roads — Itiner-e (snapshot)",
 "title_zh": "道路 — Itiner-e（快照）",
 "source": "Itiner-e route-segments export (NDJSON)",
 "source_sha256": "b1b98dcfe583585aa24b4d5742f21319b49827c205f2f089e61876fc7e326664",
 "licence": "CC-BY-4.0",
 "attribution": "Itiner-e: the digital atlas of ancient roads © 2024 by Brughmans, Pažout, de Soto and Bjerregaard Vahlstrup, licensed under CC BY 4.0",
 "crs_in": "EPSG:4326 (already WGS84 in the NDJSON — no reprojection performed)",
 "simplification": {
  "method": "Douglas-Peucker (lon/lat plane)",
  "eps_deg_by_tier": {
   "Certain": 0.0015,
   "Hypothetical": 0.004,
   "Conjectured": 0.008
  },
  "coord_decimal_places": 4,
  "note": "Douglas-Peucker only ever DROPS vertices Itiner-e already digitised, so the output can never be finer than the source regardless of eps. The eps values coarsen further for the less-accurate tiers. (Certain's eps ~167 m sits inside its own stated <50 m mountain / <200 m plains band, not above the plains figure — so on plains it draws marginally finer than the 200 m bound, though never finer than the source vertices themselves.)"
 },
 "counts": {
  "Certain": 1082,
  "Hypothetical": 805,
  "Conjectured": 13309
 },
 "shares": {
  "Certain": 0.0712,
  "Hypothetical": 0.053,
  "Conjectured": 0.8758
 },
 "dated": {
  "n": 15194,
  "of": 15196,
  "share": 0.9999,
  "note": "Itiner-e records a lower/upper date for 100.0% of road segments."
 },
 "excluded": {
  "reason": "not roads (a 'Roads' layer must not draw them)",
  "by_type": {
   "River": 834,
   "Sea Lane": 524
  }
 },
 "temporal": false,
 "is_evidence": false,
 "ground_truth_vertex": {
  "name": "Edfu Apollonopolis Magna-Berenike",
  "first_vertex": [
   33.3062,
   25.006
  ]
 },
 "tier_definitions_verbatim": {
  "headline": "The segment certainty specifies the spatial accuracy and confidence in the digitized course of the road segment.",
  "Certain": "‘Certain’ designates well-documented segments in our sources that were digitised with high spatial accuracy (less than 50 m deviation in the mountainous terrain, less than 200 m in the plains).",
  "Conjectured": "Most roads fall into the ‘Conjectured’ category, i.e. identified road segments with lower spatial accuracy due to lower level of documentation in our sources.",
  "Hypothetical": "‘Hypothetical’ is reserved for identified but not localized roads, or identified roads where physical infrastructure of the roads was less fixed or where multiple parallel tracks might have existed (e.g. desert areas, flood plains). In addition, ‘Hypothetical’ is used for roads which are speculated to have existed in Antiquity but insufficient evidence exists to classify them as either ‘Certain’ or ‘Conjectured’.",
  "_full_verbatim": "The segment certainty specifies the spatial accuracy and confidence in the digitized course of the road segment. Three values are defined: ‘Certain’, ‘Conjectured’, and ‘Hypothetical’. ‘Certain’ designates well-documented segments in our sources that were digitised with high spatial accuracy (less than 50 m deviation in the mountainous terrain, less than 200 m in the plains). Most roads fall into the ‘Conjectured’ category, i.e. identified road segments with lower spatial accuracy due to lower level of documentation in our sources. ‘Hypothetical’ is reserved for identified but not localized roads, or identified roads where physical infrastructure of the roads was less fixed or where multiple parallel tracks might have existed (e.g. desert areas, flood plains). In addition, ‘Hypothetical’ is used for roads which are speculated to have existed in Antiquity but insufficient evidence exists to classify them as either ‘Certain’ or ‘Conjectured’."
 },
 "how_to_read": {
  "en": "These are Itiner-e's own certainty tiers, which grade the SPATIAL ACCURACY of the digitised course, NOT the evidence that a road existed. A 'Conjectured' road is a real road drawn with lower spatial accuracy — it is not a conjectural road. The tiers are shown in one neutral hue; texture (solid / dashed / dotted) carries the tier, never colour, because colour is this site's genus channel.",
  "zh": "此为 Itiner-e 自有之确信度分级，所度量者乃「数字化路线之空间精度」，而非「道路是否存在」之证据。「Conjectured（推绘）」之道路乃真实存在而绘制精度较低者——并非「推测存在」之道路。三级同用一中性色相，以纹理（实线／虚线／点线）承载其级别，绝不用颜色，盖颜色为本站「属」之专用通道。"
 }
}