Citation: Clark, P., Johnson, D.E. 2011. Digital charting technology and its applications on rangelands. Society for Range Management Meeting Abstracts.
Technical Abstract: Airborne and satellite remote sensing can provide extremely useful information or just pretty pictures. The difference between these two outcomes is due largely to the quality and quantity of ground-truthing data collected to support the remote sensing effort. Collecting an adequate amount of high quality ground-truthing data, however, is difficult and very expensive using traditional field techniques. We developed a ground-based photography system for "digitally charting" vegetation characteristics by acquiring geocoded, nadir imagery with a typical field plot-sized, 1-m2 footprint and sub-millimeter ground sample distance (GSD). This system consists primarily of off-the-shelf components including a consumer-grade digital camera, monopod and head, GPS logger kit, compass, and bulls-eye level. We also developed custom software to support the photography system. GeoAlbum compiles, scales, and geocodes raw imagery while VegMeasure2 performs several innovative image classification analyses optimized for near-earth photography. Use of digital charting technologies allows rapid ground-truth sampling of vegetation cover, plant density, and species frequency for hundreds of plot areas per day across extensive landscapes. Digital charting thus reduces the large field personnel requirements typical of traditional ground-truthing campaigns. Use of these technologies also shifts the time costs of ground-truthing from the field to the office where image processing and analysis tasks can be conducted on a schedule not dictated by field conditions. Combined, the advantages of digital charting make rigorous ground-truthing possible where it was previously cost-prohibitive.