Basic GIS Coordinates Author:Jan Van Sickle Even with the use of GPS technology, it is not possible to survey accurately or use GPS properly without taking the shape of the earth into consideration and without a clear understanding of coordinate systems. Land Coordinates for Surveyors and Mappers covers ellipsoids, datums and plane coordinate systems as they are used in GIS and GPS. This ... more »new text also covers the geoid and the concepts of elevation. Each of these topics implies other issues from mapping angles to datum design. These ideas are complex, yet they are presented as a logical progression of ideas and in a manner that is neither too complicated nor oversimplified to avoid getting bogged down in the mathematics.« less