Watch the overview
42 seconds. A narrated explainer; the transcript is below. The written guide includes additional detail.
Read the video text
- 0:00A training survey uses road DEMO 02,
- 0:03but the reference contains DEMO 01. Investigate
- 0:06the identifier and source network before interpreting
- 0:09the measurements. The illustrative reference ends at
- 0:12kilometre ten, while a survey section ends
- 0:15at ten point five. Check the intended
- 0:17road and range rather than trimming the
- 0:20value blindly. Direction follows ordered survey positions
- 0:24along the reference road. If usable geometry
- 0:27or positions are missing, the check may
- 0:29not run. Skipped never means passed. Coverage
- 0:33shows where records exist, not whether they
- 0:36are correct. Project settings distinguish advisory alignment
- 0:39from findings that can gate sign-off.
Compare the identifier with the reference
The first fictional survey row uses DEMO 02, while the network reference contains DEMO 01. The identifiers are different. Before interpreting the row’s measurements, investigate the original road identity and the applicable source network. The animation highlights the failed relationship without choosing a replacement identifier.
Case or whitespace normalisation is not the same as deciding that two different roads are equivalent. Keep ambiguous or unavailable matches explicit, and retain the reference version used for the comparison.
Measure the part outside the reference
A separate survey section spans 8.5–10.5 km on DEMO 01. The illustrative reference runs from 0.0 to 10.0 km. Both are drawn on the same 0–11 km axis so that the overrun is visible and the arithmetic is auditable: 10.5 minus 10.0 equals 0.5 km.
That discrepancy does not identify the correct source value. The wrong road, reference version, endpoint or export conversion could require different remedies. Check the original survey evidence rather than shortening the section to make the check pass.
Use positions in their meaningful order
The direction illustration follows positions labelled 01, 02 and 03 along the same reference line. Their displayed chainages are 2.0, 3.0 and 4.0 km. The line draws forward through this sequence; it is a teaching diagram rather than a reconstructed vehicle journey.
When the required geometry is unavailable, the animation changes to not checked. Missing geometry or unusable ordering prevents the relevant comparison; it cannot be counted as a pass. Confirm the fields and evidence required by the actual recorded direction check.
Keep coverage and correctness separate
The final example contains five 2 km sections. Four contain records, giving 8 km with data in this deliberately simple illustration. One of those four sections has an unresolved issue. The existence of a record therefore does not mean that the section passed every check.
Real project coverage must be read with its aggregation method, internal gaps, overlapping survey types and inclusion limits. Project policy also determines whether alignment is advisory or can gate sign-off. Use the full project report and current findings to explain those boundaries.
Sources and scope
This guide describes the platform workflow; it does not establish a requirement of a TMH manual. Platform review and certification are described in the product documentation.