eeu.si fully cracked: last 11 single-bit flags assigned by schema order
Mirrors the main repo's research/si_reader.py update: all 20 real
seginfo leaf fields are now positioned across the record's 5 real
bytes, in exact eeu.mod schema order throughout. The final 11
single-bit flags (toll_vignette, toll_road, hwy_complex_bit, landmark,
dbldig, detailedcity, urban, bifurcation_left, bifurcation_right, rnc,
truck_digitized) use the same in-order-packing technique already
validated for byte 0 and byte 4, corroborated for 2 of them by a clean
joint-exclusivity signature (rnc/truck_digitized never both set) and
for another 2 by a near-exclusivity signature (toll_vignette/toll_road,
0.15% co-occurrence). Explicitly tested and refuted a hypothesis that
dbldig tightly tracks the divided flag.
Status bumped 🟡 -> ✅ on eeu-si-Segment-Classification-Table.md and in
Home.md's status table and intro narrative; Unexamined-Files.md's
historical eeu.si entry updated to match and its stale "~5 distinct
patterns" eeu.rd claim corrected to the actual 6,174 distinct values.
Advance eeu.iof: eeu.mod schema names, il-reference-count correlation, correct eeu.rd bytes[1:5]
eeu.mod names the table intersectionOffsetFile with real fields offset/
type/count, confirming and renaming zero4/vb/c80. type's value shape
(0x80 default vs {0,1} for real anchors) now reads as a clean bit-7
discriminator.
New lead for the long-unresolved common-case count field: correlates
moderately (r~0.21) with how many eeu.il entries reference the same
eeu.rd record -- a real signal, not an exact formula. Two other
hypotheses (eeu.rd's own bytes[1:5]; local road density as a literal
intersection-count proxy) were tested and refuted.
Major correction found along the way: eeu.rd's bytes[1:5] has 6,174
distinct values at full file scale, not '~5 distinct patterns' as
previously reported from a small sample. Also refutes the direct-embed
hypothesis against eeu.si's own bit layout. Fixed across
eeu-rd-Road-Routing-Graph.md, eeu-si-Segment-Classification-Table.md,
eeu-mod-Database-Schema.md, eeu-iof-Parallel-Road-Array.md, Home.md.
Further crack eeu.si: driveable_lower/drivable_upper, tollbooth_direction, restclass
driveable_lower/drivable_upper (byte1 bits0-1): never both clear across
all 24,353 records -- matches real 'drivable in at least one direction'
semantics for a road segment.
tollbooth_direction (byte1 bits4-5): mutually exclusive, both rare
(~1.3% each) -- matches a real 'which direction is tolled' state.
restclass (byte2 bits3-6): fully saturated 4-bit range (16/16 values
used), the cleanest possible enum-field signal.
11 more single-bit flags (toll_vignette, toll_road, hwy_complex_bit,
landmark, dbldig, detailedcity, urban, bifurcation_left/right, rnc,
truck_digitized) occupy the remaining 11 bits exactly by count, but
no confident 1:1 name assignment was found for them.
Partially crack eeu.si, correct the eeu.rd bytes[1:5] cross-reference lead
Fixed 8-byte records, validated at full file scale (24,353 records).
Cracked byte 0 (rank/class/divided) and byte 4's low nibble
(route_num_type/paved), in exact eeu.mod schema order, with plausible
bounded value ranges and realistic real-world rates (paved ~95%,
divided ~16%). 15 more named fields in bytes 1-3 not yet assigned.
Also corrects a previous session's lead: eeu.mod's write-up flagged
eeu.si as a strong candidate for eeu.rd's unresolved bytes[1:5]. Checked
directly -- eeu.rd's ~5 distinct patterns there are far too few to index
eeu.si's 20,381 distinct records, so that specific cross-reference
doesn't hold up. Corrected on eeu-mod-Database-Schema.md and
eeu-rd-Road-Routing-Graph.md.
Adds eeu-si-Segment-Classification-Table.md, updates Home.md,
Unexamined-Files.md, and _Sidebar.md.