ANZLIC National Nested Grids for NSW

Brief description

This set of aligned GeoTIFF GIS template rasters (also called grids) covering NSW and ACT that are aligned with the Australian ANZLIC National Nested Grid (NNG). See link in resources section for more information on the NNG. There are four sets of rasters aligned to the NNG, two in Albers projection, and two series of geographic (latitude, longitude) rasters with grid cell sizes defined in terms of decimal degrees (dd) and degrees, minutes and seconds (dms). Albers projection is often used to generate area statistics because each grid cell is equal in area. Unless there is a need to nest the Albers grids within a 10km or 5km grids it is recommended you use the series nested within the 9km grid cells. Benefits of aligning rasters to the NNG include:\r\n\r\n**Calculating areas:** Once raster models have been built, there is often a need to report on areas of each model class within classes from another data layer, such as tenure or administrative regions. To obtain accurate area calculations it is necessary to re-project the raster into an equal area projection, such as Albers which is the projection used by the NNG. \r\n\r\n**Reduces spatial errors:** Every time a raster is projected each grid cell is moved and you introduce spatial errors (<= 0.5 x cell size). If all the input grids for an analysis are already aligned, this will reduce potential spatial errors in analysis or model outputs.\r\n\r\n**Reduces processing times:** A prerequisite or undertaking any analysis involving multiple rasters is that the grid cells in each one are spatially aligned. If all the input rasters for an analysis are already aligned, this will reduce processing time required to align them.\r\n\r\n**Aligning with national raster products:** There are an increasing number of national products aligned to the NNG. For example ABS uses the NNG when generating a national grid of population and ABARES landuse data. CSIRO and TERN are also aligning their grid products to the NNG.