How is c-squares spatial searching implemented?
C-squares spatial searching is a text-match procedure, best explained using a “telephone number” analogy. For example, the author’s agency telephone number (at CSIRO Marine and Atmospheric Research in Tasmania, Australia) is +61 362 325222, where +61 is the country code (Australia), +61 3 represents a region code (Victoria and Tasmania), +61 362 represents a sub-region code (southern Tasmania), and +61 362 32 a district code (central Hobart). Thus, all subscribers in a single country (Australia) could be selected from a list by searching for the text string +61……., all subscribers from a region could be selected by searching for +61 3…. , and so on. C-squares works in an almost exactly similar manner. Using the example given in the answer to Q.8 above, searching for “7307…” will return all georeferenced items within that 10 x 10 degree square, whatever the resolution at which they have been encoded; searching for “7307:4…” will return all items within that 5 x 5 degree square
