Not necessarily...
Transition of CS students to other majors could be easier than the others in some cases. There are a great deal of computational projects within the science and engineering, could which be done, as well as possible, by the fellows who have deep ideas about the computation and implementation of simulated complex systems. As an example, I know a graduate of CS, who did changed his major to chemistry, to work on the simulation of an electro-chemical quantum reaction. He is really successful to handle the case, truly.
In such cases, one could assert that the target person might need to work hard, firstly, to construct the desired seminal background for collaboration in the new field, but this stuff is not often too tough for determined people, considerably; and the consequences would be noticeable, as the computational aspects of the project would be progressed.
So, if you are going to work on such computational subjects within your target field (GIS, or something), you better prepare a coherent SoP and assert on your goal within that. Then, your CS background would not be considered as an irrelevant background, but a to-the-point one, probably.
Best