Survey Plate

The Survey Plate is a standardized recording substrate issued in sets to survey parties operating under Survey Directive 9.12.7, on which the observations of an Environmental Survey are fixed in a form the archive will accept. A Survey Plate is not itself a measuring instrument; it is the surface to which instruments are brought, and the resulting marks — ruling, bloom, discolouration, and in twelve recorded instances a faint odour of cut cedar — constitute the survey's primary record. Plates are produced under the standing authority of the Office of the Plate Warden and are sealed, at the close of a survey, by the Office of the Commissioner for Cartographic Integrity. A survey file submitted without its plates is returned unopened to the party that sent it, a practice reaffirmed in the Fourth Concordance, Annex 2.

Composition and Issue

Survey Plates are cast in the foundries below Spiral 41, in the same works that cast the Resonance Plate family, though on a separate line and by a separate register. They measure 24 cm by 36 cm by 0.4 cm, the standard folio dimension of survey work since the Second Reconciliation of Plate Measures. The casting formula is fixed by the Warden's inventory and has not been altered since 588, save for the substitution of washed sand in the third batch of 602 following a dispute over grain. Nothing about the plate is secret; the formula is printed on the back of every plate, in reverse, so that the surveyor reading a completed record may consult it without turning the plate over.

Plates are issued in sets of nine, called a quire, of which seven are intended for use and two are held in reserve. The reserve plates are not optional. A quire returned with both reserves unmarked is recorded as complete; a quire returned with one reserve used is recorded as complete with note; a quire returned with both reserves used is recorded as complete with objection, and the objection is filed against the survey party rather than the survey, which has caused considerable irritation among parties who could not have known in advance that a fold would require three plates. Survey Verification has twice recommended that the objection fall on the survey, and twice been refused.

Use in the Field

The working of a plate is a matter of bringing the instrument to the surface and holding it still. A Class I Resonance Plate laid at the corner of a Survey Plate will indicate baseline field strength; a Class II laid against a resonant surface suppresses it, and the Survey Plate beneath records the suppression as a pale ring. Chronotropic Gradient Plates record on Survey Plates without contact, which is the only reason temporal drift can be mapped at all in folds too narrow to stand in. The plate does not discriminate between these sources. It records what occurs above it, and the surveyor is expected to annotate the margin accordingly.

Margins matter more than surveyors generally believe. The ruled margin of 1.5 cm is the only part of the plate the archive reads first, and an unannotated margin is treated as an assertion that nothing unusual occurred. Findings from The Partial Survey records that of the 214 objections raised against that survey's plates, 191 concerned margins. The clerk Orwen of Spiral 12, who annotated his margins in a hand so small that Survey Verification purchased a lens for the purpose, is now cited in the training of every survey party, usually as a caution and occasionally as a model, depending on the instructor.

The Plate Question and Its Consequences

Survey Plates are not exempt from the disorder that afflicts all platework. During the Plate Question on the seventh gallery of Spiral 9, three apertures were found bearing the same designation, and the investigation that followed discovered, among other irregularities, fourteen Survey Plates issued to a survey party whose commission had lapsed eleven years earlier. The plates had been used continuously in the interim and their records were, by the standards of the time, excellent. The Bureau of Plate Registration was constituted in the aftermath and has since held that a plate's records are valid if the plate is valid, regardless of the standing of the party that carried it. The Office of the Plate Warden has never fully accepted this and continues to stamp lapsed quires with a small mark, the meaning of which is not printed anywhere.

Dispute over the Retired Template

Survey Plates are held by some to descend from the SFU-1 template, and the Pre-Revision Plate — the retired SFU-1 casting withdrawn in 611 — is frequently exhibited alongside survey material as an ancestor. The Office of the Plate Warden rejects the descent. Its position, stated in a circular of 634, is that "the Survey Plate is a folio, and the SFU-1 is a resonator; that both are flat is a property of floors" (Office of the Plate Warden, Circular 17). The Fifth Concordance, Annex 9, takes the contrary view and lists the Survey Plate among the SFU-1's derived instruments, a listing the Warden has described in writing as "a clerical kindness to the Fifth." Both documents remain in force. Survey parties are advised to cite neither.

Retention and Disposal

Completed plates are retained in the gallery of the survey they served for a period of ninety years, after which they are transferred to the deep holdings and, eventually, resurfaced. Resurfacing is done by grinding and is not permitted on any plate bearing a seal of the Office of the Commissioner for Cartographic Integrity until the seal has been lifted, a process that requires the Commissioner's signature and, since 619, the countersignature of the Warden. Plates may not be carried between galleries without a transit slip. Plates left in stairwells are collected on the third day of each month and held at the nearest issue desk for one month before resurfacing, and may be claimed by any party able to describe the reverse of the plate without handling it.