Input Dataset

NT NVIS Version 4.1- National Vegetation Information System, NT 2012

An amalgamation of the NVIS version 3.1 and Northern Territory Forest Mapping, NORFOR. Data set was developed in order to align the NVISver3 data set (DEWHA) and the forest data sets sent to the National Forest Inventory (AFFA). 
For information on each particular map dataset see the following records on the NT Spatial data directory.

2DBCB771207006B6E040CD9B0F274EFE NVIS - National Vegetation Information System, NT Data Compilation - Land & Vegetation Branch / Natural Systems Division

2DBCB771213506B6E040CD9B0F274EFE - Norfor - Mapping the Forest Cover of the Northern Territory - 2001 

or ANZLIC numbers on ASSD

NVIS - National Vegetation Information System, NT Data Compilation - Land & Vegetation Branch / Natural Systems Division ANZNT0001001047

Norfor - Mapping the Forest Cover of the Northern Territory - 2001 ANZNT0903000039

For each survey a 'PRE1750' and an 'EXTANT" coverage was produced. The 'PRE1750' coverage or 'pre-clearing' coverage represents, in theory, the vegetation that existed in that particular survey region before the arrival of the white man. In all the surveys attributed to NVIS standard in the NT, this 'PRE1750' coverage was
taken to be the original survey coverage produced. The 'EXTANT' coverage or present day coverage represents, in theory, the present day (circa 2004) vegetation coverage. This was produced by updating the 'PRE1750' coverage with a coverage containing cleared or modified vegetation, the so called 'clearing' coverage (see comments). 

NOTE: due to text limits LINEAGE continues in completeness section

Funding Support

Access Mechanisms

By request

Dataset Lineage

The NVIS ver 4.1 refers to the NVIS-NFI integrated data set. This was produced a number of years ago by combining the NORFOR FPC data into the current NVIS2005ver3 Pre-European data set. This coverage affects the northern part of the NT. This coverage was produced in response to the need for the NVIS forest mapping data set (at level 3) and the NFI forest data set to provide the same forest area values. It was meant as an interim data set to address this rather than a complete update for NVIS. the original NVIS dataset was split at 18 degrees south into a north and south section. The NORFOR data was combined with the north section. The north and south sections were then recombined (see below). Due to software limits the north coverage needed to be tiled (13 sections) and re -combined. During the re-combining process some spatial line work errors were introduced (very narrow linear strips along some join lines). These remain in the current dataset. Pre European Data set: Brief processing history The original Pre-European Arc/Info coverage was converted to a shape-file and updated with new map unit identification attribution (NEWMAP,NVIS_NFI_MAPID). This was then converted back to a coverage. As software limits where encountered the shape-file needed to be split in two, then converted back to a coverage (aml), APPENDED together and DISSOLVED. A number of small slither polygons were removed from final coverage. Integrating the NVIS and NFI data sets has resulted in the production of a large number of new vegetation descriptions that differ only at the structural formation level (canopy cover values). This however necessitates a number of attributes to be changed. An automated process to re attribute tables was necessary and this was done by DEWHA.. Creating new veg descriptions was problematic for the existing data base as well as for SPATIAL_DATA table and mosaics. A rule set was devised to overcome this. LINEAGE CONTINUED IN COMPLETENESS SECTION

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