When to use this guide
Start with the purpose: transferring a height, establishing vertical control or checking construction. A single elevation does not describe the quality of the observation route. Prepare a record that an independent reviewer can trace to its start, end and readings.
The reference distinguishes leveling grades and route types; line length and loop length have different definitions. Do not apply one tolerance coefficient to every project or treat height-of-instrument arithmetic as approval of a vertical network.
The checklists and examples are original GeoGiza guidance, not specification text, a translation or a compliance certificate. Consult the original document and project scope for applicable grades and mandatory limits.
Edition verified; currentness unconfirmed
Publisher, edition covers and page locators were checked on 11 October 2026. Whether a later official edition supersedes these documents is unconfirmed; check with the responsible authority and the project contract before adopting requirements.
What to prepare before review
- Benchmark identifier, height provenance, check date and vertical datum.
- Purpose, agreed work grade and the authority reviewing the result.
- Original readings, units, station order and the route length definition.
- Instrument and staff details, field checks and repeat-observation records.
Practical review steps
- 1
Identify the route before selecting a limit
Record whether the work is an out-and-back line, a loop or a connection between known marks. Consult the required grade in the source, then record the limit’s locator, unit and length definition in the review file.
- 2
Reconcile readings with the field book
Use the existing level book to trace backsights, foresights and change points. Check signs and metre units; keep observation edits separate from correction distribution so the raw record remains intact.
- 3
Review closure before adjustment
Compare the unadjusted ending height with the known ending height. Request new observations or benchmark clarification when evidence is missing; distributing an error does not fix its cause.
- 4
Save the review decision and its evidence
Link the route log to its closure report, selected reference and reviewer decision. Successful arithmetic does not resolve an outstanding work-grade selection.
Understand the concept visually
Original GeoGiza teaching diagram · synthetic data · not acceptance limits or official approval
One leveling setup: from benchmark to height
A synthetic 100.000 m benchmark, 1.200 m backsight and 1.100 m foresight give HI = 101.200 m and RL = 100.100 m. HI is the level of the line of sight, not the physical instrument height above ground.
HI = 100.000 + 1.200 = 101.200 m; RL = 101.200 − 1.100 = 100.100 m
A calculated height does not by itself establish the quality or reference ties of the leveling run.
One setup on a synthetic local reference; not a run-closure example or an acceptance limit.
Consult this topic’s document locatorsSYNTHETIC teaching example — not field observations or a tolerance limit
Synthetic review example: ending height
A known ending height is 100.000 m; the unadjusted computed height is 100.006 m. The arithmetic difference is +0.006 m, or +6 mm. The record omits the work grade and route type.
What to record in the review
Record the difference and hold the compliance decision until the grade, length definition and applicable source limit are documented. This example explains a data review, not an Egyptian tolerance limit.
Mistakes affecting the review decision
- Using the combined outward and return distance instead of the source’s defined line-length variable.
- Overwriting raw observations after correction or changing a benchmark without a record.
- Treating a calculator’s elevation output as route acceptance.
Official sources and reading locators
Printed page numbers differ from PDF viewer pages. Open the official link and read the complete provision in the edition applicable to your project.
Egyptian Survey Authority · Technical reference
ESA technical specifications — Part I: surveying
First edition — 2020
- Locator:
- Chapter 2: 3, 3-1, 3-2; table 2-13
- Printed pages:
- 33–34
- PDF viewer pages:
- 54–55
Source checked:
Frequently asked questions
Does the leveling calculator certify compliance?
No. It assists elevation arithmetic. Selecting grades, routes and limits, checking observations and approving the work require an identified reference and responsible reviewer.
Where can I check leveling grades and closure limits?
In Part I of the ESA specifications, chapter 2 section 3 and table 2-13, printed pages 33–34. Use the edition required for your project and check for official updates.