Benefits of pan-sharpened Landsat imagery for mapping small waterbodies in the Powder River Basin, Wyoming, USA
Pan-sharpened Landsat imagery was used to map waterbodies of a wide variety of sizes in the Powder River Basin (PRB) in northcentral Wyoming, USA. Coal bed natural gas extraction activities have been intensive in the PRB over the past decade, with abundant co-produced water being discharged into retention ponds and small ephemeral channels. Although land management agencies are tasked with monitoring these waterbodies, traditional field survey methods might not be feasible during rapid development. Remote-sensing applications could be used in such cases. Although Landsat and similar medium-resolution datasets do not have detailed spatial information at fine resolutions required to map small waterbodies, they do contain rich spectral information. Panchromatic data collected by satellites have an appropriate spatial resolution, but lack detailed spectral information. Thus, image fusion techniques were used to create a pan-sharpened image, by merging multispectral (30-m resolution) and panchromatic (15-m) bands from Landsat 7 imagery. Both the original and the pan-sharpened images were used to map waterbodies and estimate their area, being compared to photo-interpretation results. The accuracy of mapping waterbodies with pan-sharpened imagery was significantly higher than the original Landsat data for waterbodies ranging in size from 901 to 8100 m2. Large reservoirs (>8100 m2) were very accurately mapped, both images producing identical results (96%). Neither image was able to suitably detect very small waterbodies (<900 m2). Detailed analysis within 901–3600 m2 size category revealed that the benefits of pan-sharpened imagery were most pronounced (25% higher accuracy) for mapping waterbodies ranging in size from 1801 to 2700 m2.
Document Type: Research Article
Affiliations: Department of Renewable Resources/Watershed management, University of Wyoming, Laramie, WY 82071, USA
Publication date: 2008-03-01