Grand Erg Oriental small but ancient settlement of Ghadames at the Libyan frontier. Another and better road from Hassi Messaoud goes south, also crossing the grand erg where it passes a well called "Hassi Tartrat", before reaching the erg's far side. Further south lies the Ahaggar mountains. The cities of Wargla and Touggourt lie outside the western limits of the erg. Nearby, within the accepted boundaries of the "Grand Erg Oriental", the landscape is described as being "practically free from [sand] dunes" evidently due to strong, persistent winds. Petroleum and other hydrocarbons have been extracted in Algeria, from areas in and surrounding the
Human geography human geography. Well-known geographers from this period are Fred K. Schaefer, Waldo Tobler, William Garrison, Peter Haggett, Richard J. Chorley, William Bunge, and Torsten Hägerstrand. From the 1970s, a number of critiques of the positivism now associated with geography emerged. Known under the term 'critical geography,' these critiques signaled another turning point in the discipline. Behavioral geography emerged for some time as a means to understand how people made perceived spaces and places, and made locational decisions. The more influential 'radical geography' emerged in the 1970s and 1980s. It draws heavily on Marxist's theory and techniques, and is associated with