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Land Monitor is a coordinated initiative set up by the National Dryland Salinity Program and supported by the CSIRO, Landgate, Department of Environment and Conservation, Department of Agriculture and Food Western Australia, Department of Water, Water Corporation, and the Department of Planning and Infrastructure. The project originally aimed to systematically monitor salt-affected land and remnant vegetation change over the agricultural area of south west of Western Australia.

Land Monitor I objectives were to: 

  • Map and monitor changes in the area of salt-affected land from 1988.
  • Predict areas at risk from future salinisation.
  • Monitor changes in the amount and quality of remnant vegetation and areas of revegetation from 1988.
  • Produce highly accurate digital elevation models (DEM) from which 2 metre contour intervals can be created.
  • Distribute the derived information to the end users and the community.
  • Establish a baseline for continued monitoring.

Land Monitor II

In 2001, seven government agencies agrred to continue to acquire and process satellite imagery for Land Monitor II with the aim of providing annual mapping of remnant perennial woody vegetation in the agricultural area of south west western Australia. Land Monitor II purchased, rectified and calibrated Landsat TM (25 metre spatial resolution) summer imagery and then enhanced images to produce vegetation monitoring products, which included:

  • Vegetation cover of perennial woody vegetation with annual updates,
  • Vegetation Change - describing areas of increase, decline and stability
  • Vegetation History - change over time using imagery from three monitoring years
  • Vegetation Trend, trend class and index - summarising the status of vegetation cover over time from 1990.

   The following flowchart shows the structure of the project. More information about each component of the project can be found by scrolling down this page.

landmonitor flowchart

Mapping and monitoring salinity

Recent experience has suggested that both government agencies and landholders have grossly underestimated the extent of salt-affected land.

Collaborative research work under the National Dryland Salinity Program has developed a range of tools that can be used to map areas of land affected by salinity and monitor changes in the area of salinised land. This work is based on highly sophisticated use of Landsat TM data, digital elevation models and surface water accumulation models coupled with extensive ground truthing.


Landsat scenes are available every 16 days from 1987 onwards and can be bought from archived collections. Each scene covers approximately 186 km x 186 km. Digital elevation models (DEMs) can be produced from contour data provided by the Western Australian Land Information Authority.

The research work has shown that spring Landsat images are essential for mapping saline land. Ideally, images from three years should be used, to enable an accuracy of greater than 90%, if digital elevation data are also available. Once the saline areas have been identified, the change in area over time can be determined by comparing sequences of images. This provides the only operational method for accurate detection of past trends in the area of salinised land over large areas.

 salinity_subsetsal_legend

A subset of the Land Monitor salinity product. Cream represents agricultural land.

Predicting salinity risk areas

By combining Landsat scenes, digital elevation models (DEMs) and surface water accumulation models, areas at risk from future salinisation can be predicted. Accurate, high resolution contour data are required to produce accurate predictions of salinity risk. For this reason, Landgate will produce highly accurate 1-2m contours for the agricultural region.

valley hazardvh_leg
A subset of the Land Monitor Valley Hazard product overlaid on a Landsat greyscale image. Green represent perennial woody vegetation, orange and red represent salinity, light blue represents mapped water bodies whilst dark blue to yellow represents height above flow path (0-2m) as indicated in the legend. 

Monitoring remnant vegetation and revegetation

Remnant vegetation can be monitored using summer Landsat TM imagery. Mapping and detecting trends in the extent and condition of both natural and revegetated areas have been field tested and proved accurate, within reasonable limits, by a pilot study in the Kent Catchment. Land Monitor has mapped changes in the extent and condition of remnant vegetation and revegetation since 1987.

veg_changeveg_chg_legend

A subset of the Land Monitor Perennial Vegetation Change 1990 to 2007 product.

Producing highly accurate digital elevation models

Landsat scenes purchased for the Land Monitor project from 1987 onwards are held in an archived collection. Each scene covers an area of approximately 186km x 186 km. Accurate, high resolution contour data are available for only a small proportion of the south-west. Land Monitor has produced high quality DEMs using automated techniques. Subsets of the Land Monitor DEM may be purchased for envionmental management purposes.

 

DEM_coverage

Land Monitor DEM extent overlaid with Landsat scenes.

DEM_coverage_col

Land Monitor DEM

 

Distributing the data to the community

The Land Monitor Technical Officer can provide quotes for digital or hardcopy Land Monitor products. Land Monitor now has an online map service available to assist land management and research.

Establishing a baseline for continued monitoring

The Land Monitor project will:



 

 


 

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Last updated 22/05/2008 - dan.sandison@landgate.wa.gov.au
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