Provisional Surveying

Provisional Surveying is the branch of Tower surveying concerned with places that are not yet agreed to exist. Where ordinary surveying inspects a place once and closes the scope, provisional surveying inspects a place that has been entered into the register ahead of confirmation, on the understanding that the inspection may later be withdrawn. The practice is governed jointly by the Foundation of Survey Protocols and the Directorate of Dimensional Fidelity, an arrangement that has produced four centuries of correspondence and very little agreement.

A provisional survey is opened by the issue of a Provisional Aperture, which grants a named party the right to measure a chamber whose number has not been ratified. The measurements are entered in a provisional hand, in a separate register, and are not binding on anyone until ratified under the terms of Provisional Ratification. In practice the separate register has never been audited, because auditing it would require the surveyor to treat provisional entries as ordinary entries, which would defeat the purpose of the distinction.

Procedure and the soft bound

The surveying party works to a soft bound: the furthest point at which its instruments still return a reading that the party is willing to defend. The soft bound is marked with cord, not stone. Boundary Stelae are prohibited in provisional work, since a stele asserts that a boundary is where the stele is, and a provisional boundary is precisely the boundary that has not been asserted.

Cord is used because it can be taken up again. The Metaphorical Cartographers' Guild has complained of this at intervals since the ninth recension, arguing that a cord boundary invites trespass of the sort a stele would prevent. The Directorate's answer, printed in a margin note to the standing instructions, is that trespass into a place that may not exist is not trespass but a question of precedence. Parties wishing to cross a cord are asked to submit the crossing in advance and to leave their boots at the cord.

Readings are taken with a Theta Caliper wherever planar deviation is in question, and the compasses are calibrated from Cardinal Grit before the first measurement of the day. Expeditions working the Western approaches have reported compasses filling with grit faster than the bowls can be cleaned and have taken to carrying a spare bowl, sealed, which is opened only after the cord is laid.

Incidents

The best known failure of provisional discipline is the Gamma Aperture Incident, in which a party from Surveying Party of Aperture Gamma exceeded its granted depth and recorded a chamber the register did not admit. The records of that expedition were ruled inadmissible for eleven years and were then readmitted without amendment, no ruling having been made either way. The party's last entry remains a matter of dispute between the Foundation, which holds that the entry was made under ordinary survey and sealed unlawfully, and the Directorate, which holds that a provisional entry is provisional solely because it is filed in the provisional hand, and that the party's hand was its own.

A second and quieter matter is the Prospector-General's survey of the western stairhead, undertaken in the winter of 4041 under Provisional Research Permit 4409. The survey was completed, corded, and left in place for ratification. When the ratifying clerk arrived, the cord was there, the boots were there, and the stairhead was not. The clerk recorded an absence and closed the file; the absence was later found to have been in the register rather than in the stairhead. Concordance 31-F assigns all questions arising from the delay to the Department of Temporal Reconciliation, which has not returned the file.

Disputed doctrine

The central contradiction concerns what a provisional survey measures. Seventh Spiral Survey holds that the subject is the chamber as it stands, measured to the soft bound and no further, and that any reading beyond the cord is a reading of the surveyor's intention rather than of the place. The Partial Survey holds the opposite: that a provisional survey measures only what it cannot reach, and that its proper product is a record of omission. Both are official practices of the Foundation, both were ratified in the same year, and neither has been withdrawn.

Citations are made to whichever supports the case at hand.

"Where a chamber is surveyed partially, the part not surveyed shall be entered as fully as the part surveyed, and shall be entered first."

— The Partial Survey, Clause 2

The Foundation's own commentary concedes that the clause is ambiguous as to order of entry, and that the ambiguity has not been resolved because no one has been able to establish which party benefits from a reading either way.

Accretion and closure

Provisional surveyors are required to report suspected Spontaneous Lithic Accretion in accordance with Annex Epsilon, which sets out the form of the report and the interval at which it must be repeated. The interval is three days. The form has twelve fields, of which the fourth, the party's confidence in the suspected accretion, is left blank by common consent, since filling it in would constitute a finding.

A provisional survey is closed by one of two means: ratification, which converts its readings into ordinary readings and its cord into a stele; or lapse, which occurs automatically after nine hundred days and requires no notice to the party. A lapse is not a finding against the survey. The register is amended to record that the place was surveyed provisionally and that the survey is at an end, and no further reference is made to it. Surveying parties are reminded that instruments left at a lapsed cord become the property of the floor.

The Department of Vertical Cartography has twice petitioned to have lapsed cord counted as stair furniture, and has twice been refused on the ground that furniture is fixed and cord is not. The second refusal was accompanied by a note, unsigned, observing that the petition had been made in the wrong hand.