Findings¶
Empirical + reverse-engineered facts the tool relies on. Each is tagged [VERIFIED] or [PLAUSIBLE] and date-stamped — these describe undocumented behaviour observed on 2026-07-13 and MAY change. This is a living log; see Contributing for how to update a finding.
The source taxonomy [VERIFIED · 2026-07-13]¶
From streetlevel's documentation and confirmed against live metadata:
source |
What it is | Rendered as | tracelines default |
|---|---|---|---|
launch |
regular car coverage (sometimes trekker), road-snapped | solid blue lines | ✅ kept |
scout |
trekker / tripod (sometimes car), not road-snapped | blue lines | kept unless --precision; --include-trekker to force-keep |
innerspace |
Business View indoor tripods | — | dropped under --precision |
cultural_institute |
Arts & Culture tripods | — | dropped under --precision |
photos:* |
third-party uploads (photos:street_view_android, photos:gmm_android, …) |
blue dots | never in output (Layers 0+1) |
Key nuance: the field encodes the road-snapping pipeline, not the physical platform, so
launch ⊋ car and scout ⊋ trekker. No metadata field cleanly separates car from trekker.
Pano-id format [VERIFIED · 2026-07-13]¶
- Official ids are 22 URL-safe-base64 chars encoding 16 bytes; the final char is one of
{A, Q, g, w}(only 2 meaningful bits remain). - Third-party ids:
CIHM…/CIAB…(newer short UGC) /AF1Q…(longer). streetlevel'sis_third_party_panoid=startswith("CIHM0og") or len > 22— necessary but not exhaustive;tracelines.is_official_panoidis the stricter positive whitelist (see Methodology).
Coverage-tile layer is official-only [VERIFIED · 2026-07-13]¶
A 49-tile / 7,433-pano sweep of central Bucharest returned 0 third-party panos. Photospheres at
the same coordinates were reachable only via find_panorama(search_third_party=True). See
Verification.
Multi-source comparison [VERIFIED endpoints · PLAUSIBLE density]¶
| Source | Line geometry | Reliability | Bucharest density | Output license |
|---|---|---|---|---|
| Google (streetlevel) | reconstructed from links graph |
undocumented, unstable ids, may break | highest — Romania re-driven Mar 2025 | none (ToS) |
| Mapillary | native sequence LineStrings |
documented Graph API v4, stable ids, Meta-backed | good arterials, patchier side-streets (PLAUSIBLE) | CC-BY-SA 4.0 |
| KartaView | polylines from bbox API | open but historically flaky | Telenav/Romania heritage (PLAUSIBLE) | CC-BY-SA 4.0 |
- There is no reliable + ToS-clean Google path to lines for an EEA account: the official Map Tiles API Street-View path is contractually EEA-blocked (effective 8 Jul 2025), and the 2D raster blue-line tiles carry no metadata and are barred from storage. streetlevel (ToS-gray) is the only route to Google lines. [VERIFIED]
- Run
tracelines probe --bbox … --sources google,mapillaryto measure density for your bbox before relying on any single source.
References / prior art¶
- streetlevel by sk-zk — the MIT library this stands
on; source of the coverage-tile walk,
sourcetaxonomy, and the id classifier this project hardens. - matdoes.dev Street View / pano-id write-ups — id-format and endpoint-flag details.
- Mapillary API v4 docs · KartaView terms.
Novelty of tracelines: the 3-layer positive-whitelist filter (is_official_panoid +
source == launch allowlist + connectivity), the reproducible 0-leak verification harness, and the
multi-source fusion + GUI — built on top of the prior work above.