Idrisi GIS and image-processing software

James S. Aber
Emporia State University

Idrisi software

Clark Labs (Clark University, Massachusetts) began developing Idrisi GIS and image-processing software in 1987. Idrisi was conceived by J. Ronald Eastman, who performed most of the software programming. In 2010, he received the Distinguished Career Award from the Association of American Geographers, and he continues as the chief developer for Idrisi and related GIS software. The goal of Clark Labs is research and development of geospatial technologies for effective and responsible decision making for environmental management, sustainable resource development and equitable resource allocation (Clark Labs 2014a).

Idrisi attracted an early following among university professors and government scientists, for instance NASA's Nicholas Short, a leader in satellite remote sensing of natural resources, who heartily recommended it in the early 1990s for processing Landsat imagery. Idrisi maintains a strongly international orientation, and has received substantial financial support from the United Nations and many other sources over the years. To date, it has been used by students and professionals for wide-ranging applications in more than 180 countries (Clark Labs 2014a).

Idrisi was developed primarily as a raster-based GIS that runs on PC (Microsoft) computers with a relatively simple user interface. The idea was to provide a fully functional GIS package that could be used on commonly available computers by people with moderate technical skills. Over the years, vector capability was added along with many high-end modules for image processing and statistical analysis of cartographic and remotely sensed data. In the world of GIS, Idrisi might be described as user-friendly, although some knowledge of maps and cartography is clearly useful to exploit the full potential of its more advanced capabilities. At the high end, some of its statistical and temporal-change modules are among the most advanced of any available GIS.

Multitemporal Landsat image of Cheyenne Bottoms, a large oval-shaped depression and wetland surrounded by agricultural fields, central Kansas. Based on TM band 4 (near-infrared) for 2006 (drought), 2007 (flood) and 2009 (normal), color coded respectively as blue, green and red. Bright colors represent significant changes in land cover from year to year; dull-gray colors indicate little change in land cover. The broad maroon-purple zone shows the extent of flooding in 2007; black and dark blue show perennial water bodies. CBWA - Cheyenne Bottoms Wildlife Area; TCN - The Nature Conservancy. Image processed with Idrisi following the method of Pavri and Aber (2004).

The cost was and continues to be relatively low compared with other complete GIS packages. For this reason, Idrisi has proven popular for academic users and student training in addition to its research and scientific applications. For a university student, purchasing the Idrisi starter license (fully functional) is equivalent to the cost of a typical textbook ($95), which makes Idrisi feasible for online, distance-learning courses in geospatial analysis. The low cost is also attractive for people working in agencies or countries with limited financial support.

Since 1987, Idrisi underwent numerous improvements, culminating with version 17, known as Idrisi Selva in 2012. In 2015, Clark Labs integrated Idrisi into an expanded GIS package called TerrSet, a geospatial monitoring and modeling system (Clark Labs 2014b). Additional components include modeling systems for land change, habitat and biodiversity, earth trends, ecosystem services, climate change adaptation, and carbon emissions from deforestation. Idrisi and now TerrSet have proven to be highly functional and economical GIS packages for both entry-level and high-end applications in geospatial analysis and image processing.

Idrisi namesake

The Idrisi name honors the twelfth-century Islamic cartographer, Ash-Sharif al-Idrisi. The Golden Age of Islam flourished under the Abbassid Dynasty from the mid-seventh to mid-thirteenth centuries. At its zenith in the eigth century, the Muslim empire stretched from the Atlantic Ocean to the Indus River, including most of the Iberian Peninsula, and northern Africa (Maps on the Web 2013). Many Muslim sultans cultivated science, literature, technology, art, and architecture, while most of Europe was locked in a long Dark Age. Older works were translated from Greek and Roman, and Muslim natural philosophers made many new discoveries, particularly in astronomy, mathematics, geography, geology, hydrology and agriculture.

Vikings meanwhile expanded outward from Scandinavia, and eventually Normans conquered southern Italy and Sicily during the eleventh century (Savage 1995). King Roger II Guiscard of Sicily (1097-1154) likewise cultivated science and mathematics (Davis 1998). He was particularly interested in world geography, and he collected all known information from various European and Arabic sources as well as travelers and informants.

Ash-Sharif al-Idrisi, also known as Abu Abdullah Mohammed Ibn al-Sharif al-Idrisi [Edrisi], was born into Muslim culture in 1099 (or 1100) at Sabtah, now Ceuta, a small Spanish exclave on the northwestern tip of Africa on the Strait of Gibraltar. He attended the University of Córdoba and traveled widely in western Europe, northern Africa, and Asia Minor (Jwaideh 2015). King Roger II invited al-Idrisi to join his court, and al-Idrisi came into the Christian king's service at Palermo, Sicily (ca. 1145), where he spent the rest of his life working on the project to produce maps and geographic descriptions of the known world (Davis 1998). The king provided substantial resources for map compilation, and together they selected people to travel widely, survey distant lands, and return with geographical information.

Al-Idrisi's circular world map of 1154. Africa (south) is toward the top and Eurasia (north) is toward the bottom. Obtained from Wikimedia Commons.

The book and maps were completed (in Latin and Arabic) in 1154, just a few weeks before Roger's death. These are unquestionably among the most interesting monuments of Arabian geography ... and the most voluminous and detailed geographical work written during the 12th century in Europe (Davis 1998). Al-Idrisi went on to produce a more detailed account and map for King William II, Rodger's son, in 1161. Al-Idrisi's cartographic works are considered to be the finest of the time in terms of completeness, accuracy, and portrayal on a spherical globe. He died in Sicily in 1165 (or 1166).


Return to ES 351 syllabus, ES 551 syllabus
or ES 771 syllabus. © J.S. Aber (2015).