1. A system comprising: at least one processor; a program execution environment operable on at least one network server; a first program for rendering a plurality of visualization layers that are representative of a spatial domain; a dynamic tower of instances to run the rendering of at least one visualization layer of the plurality of visualization layers of the spatial domain, the tower comprising: a first virtual system operable in the program execution environment for executing a first portion of the first program on one level of the dynamic tower, wherein executing the first portion of the first program includes invoking a continuation; and a second virtual system operable in the program execution environment for executing a second portion of the first program on another level of the dynamic tower in response to the invoked continuation, wherein the second virtual system includes at least one capability required to execute the second portion of the first program that is different from all capabilities of the first virtual system, said second portion of the first program is necessary for the rendering of the plurality of visualization layers and wherein said invoked continuation performs a level shifting operation to shift execution up or down on the levels of the dynamic tower wherein the lowest level of the dynamic tower provides a greatest common denominator of capabilities of the plurality of virtual systems and wherein the second virtual system has capabilities beyond that of the lowest level of the dynamic tower.