The refractile outer portion of the inner member of a rod or cone cell. It is located between the myoid and the outer member of the cell, and contains mitochondria. The myoid is in contact with the external limiting membrane of the retina while the outer member is next to the pigment epithelium. 2. Surface of revolution generated by rotating an ellipse about a major or minor axis.
Definition of GIS. A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. The key word to this technology is Geography â this means that some portion of the data is spatial. In other words, data that is in some way referenced to locations on the earth.
A historical geographic information system is a geographic information system that may display, store and analyze data of past geographies and track changes in time. It can be regarded as a subfield of historical geography and geographic information science. GIS was originally developed for use in environmental sciences, military and for computer assisted cartography. It is the opinion of some that the tools developed for these uses are ill suited for the features of historical data.