Satellite imaging of pastures: Frequently Asked Questions

  1. What is the Pastures from Space project?

  2. How do you measure pastures using satellite images?

  3. Can the satellites see through cloud cover?

  4. How fast do the satellites travel?

  5. How often do the satellites pass overhead?

  6. How much can the satellites “see”?

  7. Where is the Pastures from Space technology being trailed?

  8. Other satellite-based agricultural technologies

 

  1. What is the pastures from space project?

The pastures from space group is a consortium comprising CSIRO Livestock Industries, the Western Australian Department of Agriculture (DAWA), and the Western Australian Land Information Authority (Landgate).

The project involves use of remote sensing (satellite imaging) to measure pasture cover and predict pasture growth. Research has been undertaken in this field across Australia over a period of five years. Other technologies include an infrared test that allows the quality of different hays to be measured, to help farmers determine how much an animal will eat.

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  1. How do you measure pastures using satellite images?

Pasture cover (biomass) can be estimated by measuring the amount of green foliage that appears in satellite images to a square kilometre scale. This information can then be combined with meteorological information (that is, local rainfall and temperature readings) for a particular region and calculated into per hectare figures on a weekly basis. Studies undertaken by CSIRO Livestock Industries on trial sites in the south-west of Western Australia indicate that the technology developed to “read” satellite images for estimations of pasture biomass has a 97 percent accuracy, when compared to on-ground measurements.

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  1. Can the satellites see through cloud cover?

No, although there may be ways around this. One method is to use the next or previous days’ data, or images may be taken from another satellite. The satellite images are used in combination with other data not constrained by cloud cover, such as rainfall and temperature readings.

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  1. How fast do the satellites travel?

The satellites orbit 740 kilometres above Earth. They travel at the speed of Earth’s rotation.

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  1. How often do the satellites pass overhead?

Depends on the specific satellite, some pass overhead daily, while others could be between 3 and 16 days apart.

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  1. How much can the satellites “see”?

The satellites provide images of green foliage (biomass) in pastures. iFarm has developed software to assess the amount of biomass available by measuring the various levels (or ‘greenness’) of biomass. This information is combined with on-the-ground pasture and meteorological (rainfall, temperatures) data to produce a kilogram per hectare figure for targeted regions. The satellite assessments of pasture cover can be used to predict how quickly pastures are growing.

Satellite images can be as detailed as one square kilometre, however, satellite assessments should be interpreted in terms of a farmer’s own local knowledge and experience.

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  1. Where is the pastures from space technology being trailed?

The pastures from space technology has been trailed predominantly in the Mediterranean climate zone of Australia, although the technology could feasibly be used in other climate zones.

Australia:     

          WA        -        100+ sites (mostly participating farms)

          NSW      –        3 sites near Harden

          Vic        -        1 site near Hamilton

          SA         -        3 sites near Naracoorte and Goolera.

New Zealand:

          Waikato (under development)

 

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  1. Other satellite-based agricultural technologies

While not currently being undertaken by the consortium, other satellite technologies being developed as precision agricultural management techniques for farmers include tracking movement of livestock. Global Positioning Systems (GPS), used in automobiles to obtain directions, is being used at the US Department of Agriculture’s (USDA) Oregon Agricultural Research Centre. Agricultural Research Service rangeland scientist Dave Ganskopp has installed collars with special radio receivers on a dozen cattle. These receivers collect information from a constellation of 24-30 satellites that may be working at any one time. Using satellite coordinates, researchers can determine within a few metres where a cow was and what time she was there. The GPS units track when cattle roam and also monitor the animals’ head movements, which indicate whether the animals are eating, sleeping or just walking.

More details at: http://www.ars/usda.gov/is/pr/2002/020812.htm

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Copyright © 2006 Pastures from Space
Last modified: November 08, 2006

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