|
By Mathias Lemmens, senior editor, GIM International The present product survey provides an overview of commercially available software capable of assisting a wide range of researchers and practitioners, from professionals to occasional users, in the transfer of diverse satellite, aerial and ground-based imagery to maps and other types of geo-information. This survey is the third on this subject to appear in GIM International. Although all systems aim at extracting geo-information from imagery, they may vary widely in scope and historical background. For example, Clark Labs, where the remote-sensing image-processing software Idrisi was developed in the mid-80s, is based in the Graduate School of Geography at Clark University, Michigan, USA. The package, named after Abu al-Idrisi, an important twelfth-century cartographer and geographer who travelled extensively in the Mediterranean area and Central Asia, is mainly used by environmental managers and researchers in more than 180 countries. Definiens, developer of eCognition, was founded in 1994, also in an academic environment. It became a commercial enterprise in 2000 and is currently focusing on image analysis in life- and earth-sciences. Erdas calls itself ‘the inventor of commercial remote-sensing software' and accordingly Imagine is a flexible workhorse with many facilities to support the professional analyst. Like Erdas, the focus for PCI Geomatics, founded in 1982 and developer of Geomatica, is putting on the market tools for creating a wide range of products and solutions based on imagery, including maps. For the first time we are including in this PS a special section devoted to object-based image analysis (OBIA). The OBIA classification approach, which is gaining increasing in practitioner interest, groups neighbouring pixels together in regions prior to class assignment. eCognition from Definiens has been specially developed as an OBIA system, a major strength, but also accompanied by an apparent weakness: its virtually absent geometric processing and rectification capabilities. For a brief introduction to image classification and OBIA, see this month's Endpoint. Email: m.j.p.m.lemmens@tudelft.nl |
