1. A computing device-implemented method of processing a primary data record comprising location data, time data and measurement data, a spatial tree index comprising spatial tree nodes linked by pointers, each spatial tree node corresponding to a given spatial region and further including a pointer to a respective time tree index, and a plurality of time tree indexes, each time tree index corresponding to a respective spatial tree node and comprising time tree nodes linked by pointers, wherein each time tree node corresponds to a given time period, the method comprising: writing the primary data record to a primary data table; determining whether a spatial tree leaf node exists which corresponds to the spatial region that includes the location data; on a negative determination, generating a spatial tree leaf node which corresponds to the spatial region that includes the location data, and creating or updating spatial tree nodes connecting the spatial tree leaf node to a spatial tree root node; for the spatial tree nodes which correspond to each region that includes the location data, updating the respective time tree index by: determining whether a time tree leaf node exists which corresponds to the time period that includes the time data; on a negative determination, generating the time tree leaf node which corresponds to the time period that includes the time data, and creating or updating time tree nodes connecting the time tree leaf node to a time tree root node; and updating the time tree leaf node to include a pointer to the primary data record, wherein the spatial tree index is a quad tree index, such that the spatial tree root node corresponds to an overall spatial region and each higher level of the spatial tree index includes 4 n−1 n th level spatial tree nodes, each of the n th level spatial tree nodes corresponding to a spatial sub-region formed by dividing the overall spatial region into 4 n−1 equal sized parts, in which n is equal to a number of connections between the spatial tree root node and an n th level spatial tree node plus one.