Development of a digital protocol for vegetation mapping

Abstract

Softcopy photogrammetry has proven useful to reduce mapping time with aerial photography and aids in producing a digital product that is easily transferable over other electronic media. This study brings together computer stereo viewing with scanned aerial photos in a GIS to produce a fully digital protocol for mapping vegetation to the formation level. Erdas Imagine was used to generate digital images from aerial photos, Erdas Orthobase was applied to orthorectify the images through a joint triangulation solution for 42 photos, and Erdas StereoAnalyst provided on screen stereo viewing for vegetation delineation. Vegetation polygons were then classified using the National Vegetation Classification System formations in ArcView 3.2, and a thematic accuracy assessment was carried out on the vegetation map using the USGS-NPS standards. A positional accuracy assessment was conducted on the photo mosaic produced from the orthorectified images. Thematic accuracy was 77.55% initially, and the revised map had an 88.70% thematic accuracy. Positionally, the photo mosaic had Class 1 positional accuracy along the X-coordinate with 0.603 meters RMSE and had Class 2 accuracy along the Y-coordinate with 2.415 meters RMSE. A protocol using entirely digital methods was produced with the software cited that meets the formation level USGS-NPS vegetation mapping standards.