SA Mapsheet Referencing

General

  1. Each map of the National Map Series is identified by its unique number (e.g. 2830CB) and scale, or by name (e.g. 331 8 Cape Town, 1: 250 000).
  2. All maps produced by the National Geo-spatial Information are referenced to the Hartebeesthoek 94 Datum (WGS84 ellipsoid).

Degree Square Breakdown

  1. The degree square measurement mentioned within this section is based on the geographical coordinate system or graticule, defined by latitude and longitude.
  2. Each degree square is designated by a 4-digit number, made up of the integer values of the Latitude and Longitude respectively, at iHartebeesthoek 94 Datum (WGS84 ellipsoid)ts NW corner (e.g. 2830) as indicated in Figure 1.2.1
  3. Each degree square is further divided into four quadrants, each covering an area of 30' latitude x 30' longitude (quarter degree square). These quadrants are lettered A,B,C and D (capital letters) respectively in a top down, left to right sequence as indicated in Figure 1.2.2 . This will form the fifth alphanumeric identifier for maps of the National Map Series (e.g. 2830C.
  4. Each quarter degree square is further divided into four quadrants, each covering an area of 15' latitude x 15' longitude. These are lettered A, B, C and D respectively as indicated in Figure 1.2.2. This breakdown forms the sixth alphanumeric identifier for maps of the National Map Series. The area highlighted in Figure 1.2.2 and Figure 1.2.3 section (b) indicates the coverage of sheet 2830CB of the 1:50 000 map series.
  5. Each 15' latitude x 15' longitude is further 1:10 000 Orthophoto map seriesdivided into 25 components, each covering an area 3' latitude x 3' longitude. The resultant components are numbered from 1 to 25, increasing in a top down, left to right sequence. These numbers form the seventh and eighth alphanumeric identifiers that are preceded by the six- digit identifier as depicted in Figure 1.2.3 section (a) and made up of integer values. This map reference is specific to the 1:10 000 Orthophoto map series. In the Figure 1.2.3 section (a), the highlighted area indicates the coverage of sheet 2830CB1 of the 1:10 000 Orthophoto map series.

 

The 1: 50 0000 Topographical Map Series

Map Series

The 1: 10 000 Orthophoto Map Series

  1. Each orthophoto map covers an area of 3' of latitude by 3' of longitude.
  2. The graticules of sheet extents are devisable by 3' and exceptions in cases of extended maps are listed in the document – "Schedule of Map Extent Exceptions".
  3. Each orthophoto map has a unique seven or eight digit alphanumeric identifier as detailed in Fig 1.2.3 (a). In addition to the alphanumeric identifier, each orthophoto map has a name that is derived from a prominent feature on the map.

The 1: 50 0000 Topographical Map Series

  1. Each 1: 50 000 topographical map covers an area of exactly 15' of latitude by 15' of longitude.
  2. The graticules of the sheet extents are devisable by 15' and exceptions in cases of extended maps are listed in the document – "Schedule of Map Extent Exceptions".
  3. Each 1: 50 000 topographical map has a unique six digit alphanumeric identifier as detailed in Fig 1.2 .3 (b), eg 2830CB.
  4. In addition to the alphanumeric identifier, each 1: 50 000 topographical map has a name that is derived from a prominent feature on the map.
  5. Both the six digit alphanumeric identifier and the name is unique across the entire 1: 50 000 topographical map series.

The 1: 100 000 Topographic/Land Cover Map Series

  1. With the exception of combined/extended maps, each 1: 100 000 topographic/land use/cover map extends over an area of exactly 30' of latitude by 30' of longitude.
  2. Exceptions of extended maps are listed in the document – "Schedule of Map Extent Exceptions", and are named according to the naming conventions listed
  3. The graticules of the sheet extents are devisable by 30' and exceptions in cases of extended maps are listed in the document – "Schedule of Map Extent Exceptions".
  4. Each 1: 100 000 topographic/land cover map has a unique five digit alphanumeric identifier as detailed in Fig.1.2.3 (c) e.g. 2830C.
  5. In addition to the alphanumeric identifier, each 1: 100 000 topographic/land cover map has a name that is derived from a prominent feature on the map.
  6. Both the five digit alphanumeric identifier and the name are unique across the entire 1: 100 000 topographic/land cover map series.

The 1: 250 000 Topographical Map Series

  1. With the exception of combined/extended/overlapping maps, each 1: 250 000 topographical map covers an area of exactly 1° of latitude by 2° of longitude.
  2. Exceptions of combined/extended maps are listed in the document – "Schedule of Map Extent Exceptions", and are named according to the naming conventions listed
  3. The latitude defining the sheet extents shall be devisable by 1°.
  4. The longitude defining the sheet extents shall be devisable by 2°.
  5. Each 1: 250 000 topographical map has a unique four digit alphanumeric identifier derived from the 4-digit number made up of the integer values of the Latitude and Longitude respectively at its North West corner.
  6. In addition to the 4 digit alphanumeric identifier, each 1: 250 000 topographical map has a name that is derived from a prominent feature on the map.
  7. Both the four digit alphanumeric identifier and the name are unique across the entire 1: 250 000 topographical map series.

The 1: 500 000 Topographical / Aeronautical Map Series

  1. With the exception of combined/extended/overlapping maps, each 1: 500 000 topographical/aeronautical map covers an area of exactly 2° of latitude by 4° of longitude. Exceptions of extended maps are listed in the document – "Schedule of Map Extent Exceptions", and are named according to the naming conventions listed
  2. Each 1: 500 000 topographical/aeronautical map has a unique four digit alphanumeric identifier derived from the 4-digit number made up of the integer values of the Latitude and Longitude respectively at its North West corner.
  3. In addition to the alphanumeric identifier, each 1: 500 000 topographical/aeronautical map has a name that is derived from a prominent feature on the map.
  4. Both the four digit alphanumeric identifier and the name are unique across the entire 1: 500 000 topographical/aeronautical map series.

The 1: 1 000 000 International Civil Aviation Organisation World Aeronautical Charts

All provisions listed within this sub-section (B 2.6) are subject to the International Standard and Recommended Practice – Annex 4 to the Convention on International Civil Aviation

  1. Each 1: 1 000 000 ICAO Aeronautical chart shall cover an area of 4° of latitude by 6° of longitude with a north and east overlap of 15'.
  2. Each 1: 1 000 000 ICAO Aeronautical chart shall have a unique four digit numeric identifier according to Appendix 5 – Sheet layout index for the world Aeronautical chart – ICAO 1:1 000 000.
  3. In addition to the numeric identifier, each 1: 1 000 000 ICAO Aeronautical chart shall have a name that is derived from a prominent city or town that map covers.
  4. The 1: 1 000 000 ICAO Aeronautical chart numbering system is based on Annex 4, Appendix 5 of the ICAO International Standards and Recommended Practices.