Geographic Information System is probably the most useful tool for geographers to come onto the scene since the computer. GIS allows geographers to manipulate data, define searches, and study spatial relationships with relative ease. It is such a powerful and useful tool that many disciplines ranging from wildlife management to planning to agriculture to architecture all have found uses for it. Examine non-geography major students taking upper level geography classes and all but a few of them will be enrolled in GIS classes.
GIS has long been at the center of controversy; however. When it first came out to the general public some in academia decried it as a tool of the establishment. Saying that it was evil because it was first developed by the "military-industrial complex" or that it did not take into account those who would be disenfranchised. A tool, much like Microsoft Word, was declared bad. To this day some Marxist et al. geographers have attempted to reform/corrupt GIS. One of the major geographical journals just published an article on a feminist critique of GIS and how it should be more subjective to factor in feelings. (Do not ask Catholicgauze how this is to be done; somethings are beyond my comprehension)
GIS has been immune from attacks like this. Many of those who use GIS are not in academia but in the career world and have no time for post-structuralist thought. This independence can turn into isolation and secession.
There are those who worship GIS as a thing in and of itself. Some schools like Harvard only teach how to do GIS while calling it geography. Others have started Geographic Information Science programs which dedicate themselves solely of the study of GIS.
With GISc focusing only on GIS, the whole reason GIS exists, to study spatial phenomenon, is kicked out the door. When GIS is the pinacle of everything geography loses. What has happened is that many GIS users have no knowledge of geography. With a few clicks of a button a GIS jockey can describe data's distribution but cannot explain why things are the way they are. A monkey can do that work.
To continue down this road would be a disaster for both geography and GIS. If GIS goes its own route under a banner of GISc while GIS operating tools become easier to operate, a "tech schoolization" of the tool will occur. It will become something to outsource to the lowest bidder and require no thought. GIS users could become the next administrative assistants. Once touch typing abilities were highly valued, no longer. Intelligent people need not apply in this future. A split would also hurt geography. Many departments receive a large share of their funding due to work they do with GIS. Geographers need GIS to survive in this economic system. GIS needs geography to give it a special meaning no other subject can.