NBA2018_National_wetland_map5_and_confidence_map_AEA

NWM5_20181105_v2_AEA

Spatially representing of the confidence we have that the location, extent and HGM units of the inland wetland ecosystem types of South Africa are well represented.

The National Wetland Map version 5 is packaged together with the confidence map so that users are aware of areas of low versus high confidence.

Van Deventer, H., Smith-Adao, L., Mbona, N., Petersen, C., Skowno, A., Collins, N.B., Grenfell, M., Job, N., Lötter, M., Ollis, D., Scherman, P., Sieben, E. & Snaddon, K. 2018. South African National Biodiversity Assessment 2018: Technical Report. Volume 2a: South African Inventory of Inland Aquatic Ecosystems (SAIIAE). Version 3, final released on 3 October 2019. Council for Scientific and Industrial Research (CSIR) and South African National Biodiversity Institute (SANBI): Pretoria, South Africa. Report Number: CSIR report number CSIR/NRE/ECOS/IR/2018/0001/A; SANBI report number http://hdl.handle.net/20.500.12143/5847.

There are no access limitations for this item.

There are no use limitations for this item. The confidence rating map and artificial wetland map should always be consulted to assess whether the NWM5 is fit for purpose. Please see Van Deventer et al., 2018 for more information.

WGS 1984

Projection: Albers

False_Easting: 0.0

False_Northing: 0.0

Central_Meridian: 25.0

Standard_Parallel_1: -24.0

Standard_Parallel_2: -33.0

Latitude_Of_Origin: 0.0

Linear Unit: Meter (1.0)

National Wetland Map 5 was released on 2019/10/03. It is associated with the third and final version of the South African Inventory of Inland Aquatic Ecosystems (SAIIAE) Report of 2018 or in short, the Inventory Report. National Wetland Map 5 includes inland wetlands, some rivers and estuaries, but is associated with river line data and many other data sets within the South African Inventory of Inland Aquatic Ecosystems (SAIIAE). In particular, National Wetland Map 5 should be used together with the artificial wetlands layer.

A confidence map was compiled to identify areas where the extent and HGM units attained a higher level of certainty [code 5] compared to other areas [code 1]. For the purpose of the SAIIAE, higher levels of certainty are associated with areas that have been visited in-field by a wetland specialist(s) over multiple seasons and cycles of the hydroperiod of a wetland, and are therefore likely more accurately represented in the dataset. Accuracy reflects the degree to which the spatial boundaries and/or attributes of the wetlands match those in the real world. A higher confidence score would imply an increase in accuracy, assuming that the spatial boundaries of a wetland had been informed by water, soil and vegetation indicators, and recorded with differential GPSs. Low confidence scores would imply the inverse.

The confidence rating map should always be consulted to assess whether the NWM5 is fit for purpose. The confidence of rivers, estuarine and coastal ecosystems is not reflected in this confidence map. In general, areas mapped as Low confidence may have a 50% omission error, though the commission error may have been reduced to < 10% compared to the previous versions of the NWMs. The appropriate scale of use would be 1:50 000. Where the confidence rating is Low to Medium, Medium and Medium to High, the omission error was estimated to be < 30% and the commission error < 10%.

Please see Van Deventer et al. (2018) for more information.

SANS 1878

FGDC-STD-001-1998