Aerial sketch mapping was developed in the 1940s as a technique for quickly identifying and mapping infestations of forest pathogens and insects. Observers sketched the locations of infestations on paper maps while flying transects over a survey area. With new technology of touch-sensitive computer displays and integrated GIS/GPS software, it’s possible to enter survey data directly in a computer. The Nature Conservancy (TNC) became interested in this technique as an alternative to traditional image-based remote-sensing methods for early detection and monitoring of infestations of invasive plants in the Hells Canyon region of Idaho and Oregon. Working from the United States Forest Service (USFS) Digital Area Sketch Mapping (DASM) system, TNC customized ArcPad software and added custom tools to assist with aerial mapping.
Although chartered aircraft time can be expensive, the DASM technique allows surveying of large landscapes in a manner that is more cost efficient than either ground-based surveys or other remote-sensing techniques. ArcPad is a powerful mapping application that is easy to use and affordable. This should allow land management agencies and other organizations to train existing personnel in these survey techniques for their invasive species survey and monitoring needs. More information is available online at http://www.esri.com/news/arcnews/fall05articles/tnc-uses.html
Originally published as part of the article, "Wallowa Canyonlands" in the Spring 2012 Issue of TechLine Invasive Plant News, Western Range & Wildlands Edition.