Topographical Vector Data – Northern Cape

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Publisher: Chief Directorate : National Geo-spatial Information : 2017-01-01T00:00:01

Contributors

Contact Person:  Raoul Duesimi
Chief Directorate : National Geo-spatial Information
 

Abstract

NGI topographical vector data content is arranged according the following themes, Cultural, Hydrography, Hypsography, Land Cover Land Use, Physiographic and Transportation. Cultural data content contains features that describe the cultural geography of human settlement. It represents the cultural ecology (human adaption to social and physical environments) within a country. Hydrography data content contains hydrological and coastal features. Hydrological features represent the accumulations of water on the land surface and include man made accumulation such as dams and reservoirs. The coastal features represent the physical relationship between the land and the sea. Hypsography data content contains topographical features that represent the measurement of elevation above mean sea level.Typical examples are contours and spot heights. Land Cover Land Use data content contains features that present/describe the land use and land cover within a country. The land use is presented as a vector dataset, unlike the land cover thematic which is a raster based dataset.This dataset only contains vector data for both land use and land cover. Typical examples of natural forms are Boulder, Cave, Cliff, Donga, Dune, Eroded Area, Gorge, and Mountain etc, and typical examples of artificial landforms are a Cutting, Embankment, Excavation, Mine Dump and Open Cast Mine etc. Transportation data content Contain features that represent the transportation facilities and transportation nodes of a country. It represents a connected network of passages that facilitate the transport and movement of goods and people. The dataset coverage is national and each feature instance carries attribute data that describe the classification, capture method, capture source, CUID (custodian unique ID) ,the vintage of the source and describes the correspondence with the SAGDaD(South African Geospatial Data Dictionary ) a feature content dictionary for South Africa, SANS1880.

Description

The primary source used for compiling topographical vector data is NGI orthorectified imagery having a spatial resolution of 0.5 gsd and a planimetric accuracy of 5m. All compiled data will conform to a planimetric accuracy of 10m except for contours and rivers. Historically the data was vectorised form cartographic map separates and later structured for input into the geospatial database. This was followed by mono digitising from 1:50 000 and 1:30 000 panchromatic photography having a spatial resolution of 0.75m gsd. The primary source used for river and contour data is vectorised cartographic map separates however the data is updated and edited with new photography. The maximum expected planimetric error on these features is 40m.The current vintage of the national dataset is between 1996 and 2014.

Identifiers

Local: bb06e0448187ac97f4a94241c706c5a8
Identifier Type:  DOI
Identifier: DummyDOI8323
URI:

SANS 1878

Dataset Scale:  40000
Usage Contraints:  copyright
Usage Contraints:  copyright
Coverage begin date:  2001-01-01T12:00:00
Coverage end date:  2015-01-01T12:00:00