Method and system of downloading image tiles onto a client device

A method of downloading image tiles onto a client device, the client device having an output device and being connectable to a sever via a communication network,

• the server storing a plurality of image tiles organized in a hierarchical structure, each level of the hierarchical structure storing a sub-set of the plurality of image tiles being associated with a particular resolution level,
• the method executable at the client device,
• the method comprising:
• receiving a request for an image view, the image view being associated with a first viewport and a first resolution level;
• transmitting, to the server, a first request for a first set of image tiles, the first set of image tiles for enabling the client device to display a requested image view on the output device, the first set of image tiles being part of a plurality of image tiles of the first resolution level;
• the first request being further configured to cause the server to prepare a second set of image tiles, the second set of image tiles for enabling the client device to display a different image view, which is:
• associated with a second viewport at least partially overlapping with the first viewport;
• and
• having a second resolution level being lower than the first resolution level;
• each given image tile of the second set of image tiles having four child image tiles in the plurality of image tiles of the first resolution level as prescribed by the hierarchical structure;
• receiving, from the server:
• the first set of image tiles;
• the second set of image tiles, the second set of image tiles excluding a subset of second set of image tiles each one of the subset of second set having all four child image tiles in the first set of image tiles;
• receiving a request to change the first viewport to a third viewport;
• rendering and displaying a transition view, the transition view made up of the second set of image tiles and the respective child image tiles in lieu of the subset of second set of image tiles;
• transmitting, to the server, a third request for a map tiles native to the third viewport required for displaying the third viewport;
• rendering the third viewport using the map tiles native to the third viewport;
• replacing the transition view with the third viewport.