Monitoring cross-border trails using airborne digital multispectral imagery and interactive image analysis techniques

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.

Delineating new foot trails within the US-Mexico border zone using semi-automatic linear object extraction methods and very high resolution imagery

“…Cao et al (2007) used a map-to-image swipe technique that can be used manually to join new-trail segments and eliminate false positives in a manual process employing remote sensing software data layer flicker, swipe and vector digitization capabilities. A map or GIS layer depicting pre-existing trail networks may assist an image analyst in successfully delineating new trails.…”

“…Such imagery also enables trail delineation for areas that are difficult to reach on foot or that are dangerous due to rough terrain, thick vegetation, private ownership, encounters with wildlife, or potential conflicts with smugglers or illegal immigrants (Kaiser et al 2004). However, the time and expense involved in updating digital maps of trail networks on a frequent basis needs to be minimized if such mapping and updating is to be implemented operationally by agencies such as USBP (Cao et al 2007).…”

“…The USBP has considered the feasibility of using geographic information system (GIS) and global positioning system (GPS) technology to map and monitor the trail networks, but found that terrain, weather conditions and the time and labour involved in generating and updating trail maps in such a manner are prohibitive (Cao et al 2007;Kaiser et al 2004).…”

Validating the Remotely Sensed Geography of Crime: A Review of Emerging Issues

“…To try to detect where drug, human and arms smugglers were traveling through the landscape, Kaiser and others (2004) [86] used ADAR (Airborne Data Acquisition and Registration) 5500 mounted on a helicopter to try to detect trails crossing the desert border along the southern limit of the United States. Cao and others conducted a similar study in 2007 [87]. Coulter and others (2012) [88] used a Canon EOS 5D Mark II camera system fixed on a light aircraft to detect the active movement of people through the landscape in near-real time.…”

GIS-Based Borderlands Modeling and Understanding: A Perspective

“…Earth observation can play an important role in borderlands monitoring and management. Airborne digital multispectral imagery and interactive image analysis techniques have been used to monitor cross-border trails [42]. The European Commission (EC) and the European Space Agency (ESA) have launched a joint program, namely Global Monitoring for Environment and Security (GMES), to monitor the marine and land environment in an operational context [43].…”