GB/T 7931-2008Specifications for aerophotogrammetric field work of 1:500 1:1 000 1:2 000 topographic maps (English PDF)

3 General principles

4 Layout of photo control points

5 Survey of basic control points

6 Surveying of photo control points

7 Mapping by the combined method

8 Field annotation of photographs

9 Map sheet edge matching, inspection and acceptance, and submission of results

Foreword

This document was issued on 20 June 2008 by the State Administration for Market Regulation and the Standardization Administration of the People's Republic of China, and has been in force since 1 December 2008.

It replaces GB 7931-1987.

Classification: ICS 07.040, CCS A 77.

About this edition

GB/T 7931-2008 is the current edition. It was issued on 20 June 2008 and has been in force since 1 December 2008, replacing GB 7931-1987.

GB 7931-1987 has been superseded: a specification that still cites it is citing a withdrawn edition.

The interval between issue and effect is the transition period. It exists so that producers, laboratories and buyers can requalify products, revise procedures and use up documentation before the new text becomes the one that applies. The date on this page is the official one from the record of the Standardization Administration.

Edition history and citation

GB/T 7931-2008 replaces GB 7931-1987. A specification, drawing or test report that cites the older number is pointing at a document that is no longer the one in force, and the two editions can differ in requirements, in test methods or in scope.

Where an edition is replaced, the Chinese standardization system keeps the number and changes the year: the number identifies the subject, the year identifies the text. That is why a citation without a year is ambiguous and a citation with one is not.

Classification and status

GB/T 7931-2008 is classified under ICS 07.040, in the field of natural and applied sciences. ICS is the International Classification for Standards, the same scheme used by ISO and by the national bodies of most countries, which is what allows a Chinese standard to be placed beside its foreign counterparts on subject rather than on number.

Its Chinese Standard Classification code is CCS A 77. CCS is the domestic scheme, a letter for the sector and two digits for the subject within it, and it is the code by which the standard is filed and searched in China.

The GB/T prefix marks a recommended national standard. It is not, in itself, law: it becomes binding when a contract names it, when a regulation or a mandatory standard refers to it, or when a producer declares conformity with it. In practice that covers most of the cases in which it will be read — a purchase specification, an inspection agreement or a certification scheme.

How this standard is designated

The full designation is GB/T 7931-2008. A citation should carry the number with its year, because the year identifies the text that applies.

In a catalogue or a filing system it is found under ICS 07.040 and CCS A 77 — the international classification and the Chinese one, which are the two codes by which a standard on this subject is searched.