This chapter introduces some results obtained from new applications of digital photogrammetry for forest growth and topographic changes. They are byproducts of our attempt toward the development of the field of photo-ecometrics. The goal is to provide low-cost yet accurate estimates of as many important biophysical parameters as can be measured and inferred with high resolution remote sensing data. Six strategies for information extraction from remotely sensed data are introduced: image classification, statistical regression, linear feature extraction, 3D surface modeling, radiative transfer modeling and inversion, and change monitoring. Accuracies of traditional multispectral image analysis algorithms of remotely sensed data are low. Traditional photo interpretation is error prone and expensive. We advocate the use of digital surface model (DSM) that contains the elevation of all surface features such as buildings and trees rather than digital elevation model (DEM) that has been traditionally used only for the terrain. Data fusion should not be considered only as integrating data acquired from different sources but also data (information) extracted from the same source of data with different strategies. This can be partly realized by new image analysis strategies that make use of the 3D surface information from stereo images and the multispectral, texture and contextual information inherent in the imagery. With digital photogrammetry, it has been proven that digital aerial images can be georeferenced and orthorectified to an accuracy of one to several meters. With the georeferenced and orthorectified digital images and many biophysical parameters accurately determined we can detect changes of species composition, height, crown closure, and diameter of forested land and topographic features. These same techniques will not only significantly improve our ability to economically assess the accuracy of vegetation and thematic maps but also provide alternatives to detailed mapping of geomorphological features such as landslides, surface mining, land erosion and material deposition. Illustrated in this contribution is the usefulness of DSM and orthophotos generated with digital photogrammetry in the monitoring of changes gully erosion, water channel incision and coastal salt flat zone displacements.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Photo Ecometrics for Natural Resource Monitoring
- Springer Netherlands
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