Monitoring cross-border trails using airborne digital multispectral imagery and interactive image analysis techniques |
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| Authors: | L Cao D Stow J Kaiser L Coulter |
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| Institution: | 1. Department of Geography , San Diego State University , 5500 Campanile Drive, San Diego, CA, 92182, USA lina.cao@geog.utah.edu;3. Department of Geography , San Diego State University , 5500 Campanile Drive, San Diego, CA, 92182, USA |
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| Abstract: | The objective of this study was to evaluate image-based procedures for monitoring cross-border foot trails in the US – Mexico border zone in eastern San Diego County using airborne remote sensing techniques. Specifically, digital multi-spectral and multi-temporal imagery from an airborne digital multi-spectral imaging system, digital image processing, and visual image analysis techniques were explored in the context of detecting and delineating new trail features and updating trail GIS layers. Three trail updating approaches: map-to-image (M-I) overlay, map and image-to-image (M/I-I) differencing, map and image-to-image (M/I-I) swiping and two types of spectral transform, PCA and NDVI, were tested and compared. The M-I overlay was found to be the most reliable trail updating approach. The optimal image enhancement method for the M-I overlay approach varied with vegetation structure. PCA imagery yielded better results than NDVI imagery in a highly disturbed area and NDVI imagery performed better in a densely vegetated area. The M/I-I swiping approach was useful for distinguishing misregistered extant trails from new trail features. |
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| Keywords: | Digital airborne multi-spectral imagery Foot trail Linear feature extraction GIS update |
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