Passive satellite data are based on sensors relying on reflectance of solar energy back to the sensor or detector. Different types of indices can be developed to facilitate the interpretation of images and estimation of different land areas. It is also possible to obtain time-series data for the desired land-use systems, since satellites cover the land-use systems of any project location continuously and regularly.
The smallest unit to be identified depends on the spatial resolution. At a spatial resolution of 30 m, units as small as 1 ha can be identified (IPCC 2006). More information on passive satellite data and steps for project area and boundary estimation is given in Chapter 14.
Material required includes images (purchased or downloaded) and computer software. Further, knowledge of digital image processing is required.
22.214.171.124 Merits and Demerits of Passive Satellite Data
• Available as time series covering long durations
• Applicable for land areas that are inaccessible or large
• Suitable for project monitoring phase
• Fuzzy boundaries between land-use systems can be hard to distinguish
• Different stages of vegetation growth/degradation can be difficult to distinguish
• Clouds can disturb the image
• If there are multiple land units that are far apart, more images are required
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.