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nsw_lidar

Mapping from NSW Lidar

NSW Spatial Services have undertaken a program to map all of NSW using lidar (light detecting and ranging) For details, see information on their elevation program.

Elevation data can best be accessed through the Geoscience Australia ELVIS program.

It can then processed with a GIS such as QGIS to create useful topographic maps. Instructions below are specifically for use with QGIS, though the general outline may be useful for other GISs.

Topics

The original topics here have now been moved to their own pages.

Any feedback/suggestions of improvements are welcome.

Managing DEMs

  • Merging DEMs - how to merge DEMs in QGIS
  • Managing large DEMs - while data can be downloaded in an ad hoc manner, if you are regularly processing NSW DEMs, it is better to have the DEM tiles already downloaded. This page provides steps to do this in an automated manner.

Topographic maps

There are several primary data items for topographic maps that can be generated using the DEM data from the NSW Lidar.

  • Hydrologically correct DEM - prior to further operations, it is usually important to make sure that your DEM is free of depressions. Otherwise these will mess up streams and possibly contours.

Once you have a depressionless DEM, the following items can be generated:

Styles

  • Styling - download basic style files

Automation

  • Basic map creation - a set of PyQGIS scripts that will create (and optionally save) a basic topographic map. This map can be used in QField

Mobile apps

  • QField - QField is an excellent Android app for for viewing projects created with QGIS

Dumping Ground / WIP

Resources

Method

The below snip of Breakfast Creek makes use of TPI calculated from a LIDAR derived DEM. Only positive values for TPI as displayed, which indicate cliff-like features. It is then combined with contours and aerial imagery to convey the terrain of the area.

TPI from LIDAR DEM combined with contours and imagery to show clifflines and terrain

nsw_lidar.txt · Last modified: 2021/02/19 23:01 by bushwalking