A computing system , comprising: a processor ; a display for rendering a shared map calendar comprising a continuous, manipulatable sequence of data organized as units of time within a coordinate plane; a network interface for communicably coupling the computing system to a remote computing system ; and a computer readable medium comprising code to direct the processor to: implement a state change module configured to receive, from the remote computing system , a change notification corresponding a change in a zoom level and a pan level of the shared map calendar; implement an identification module configured to retrieve an identification, ID, value corresponding to the change in the zoom level and pan level from a first data structure; and implement a replica module configured to retrieve the change in the zoom level and pan level from a second data structure using the ID value as an index value; and render the shared map calendar on the display according to the change in the zoom level and pan level; wherein the first data structure is an interval collection tree that comprises the ID value corresponding to the change in the zoom level and pan level; wherein the second data structure is a map data structure that comprises a plurality of key-value pairs, wherein a key of a key-value pair is the ID value corresponding to the change in the zoom level and pan level, and the value is the change in the zoom level and pan level. a processor ; a display for rendering a shared map calendar comprising a continuous, manipulatable sequence of data organized as units of time within a coordinate plane; a network interface for communicably coupling the computing system to a remote computing system ; and a computer readable medium comprising code to direct the processor to: implement a state change module configured to receive, from the remote computing system , a change notification corresponding a change in a zoom level and a pan level of the shared map calendar; implement an identification module configured to retrieve an identification, ID, value corresponding to the change in the zoom level and pan level from a first data structure; and implement a replica module configured to retrieve the change in the zoom level and pan level from a second data structure using the ID value as an index value; and render the shared map calendar on the display according to the change in the zoom level and pan level; wherein the first data structure is an interval collection tree that comprises the ID value corresponding to the change in the zoom level and pan level; wherein the second data structure is a map data structure that comprises a plurality of key-value pairs, wherein a key of a key-value pair is the ID value corresponding to the change in the zoom level and pan level, and the value is the change in the zoom level and pan level. implement a state change module configured to receive, from the remote computing system , a change notification corresponding a change in a zoom level and a pan level of the shared map calendar; implement an identification module configured to retrieve an identification, ID, value corresponding to the change in the zoom level and pan level from a first data structure; and implement a replica module configured to retrieve the change in the zoom level and pan level from a second data structure using the ID value as an index value; and render the shared map calendar on the display according to the change in the zoom level and pan level; wherein the first data structure is an interval collection tree that comprises the ID value corresponding to the change in the zoom level and pan level; wherein the second data structure is a map data structure that comprises a plurality of key-value pairs, wherein a key of a key-value pair is the ID value corresponding to the change in the zoom level and pan level, and the value is the change in the zoom level and pan level. <EOS>