ZXY Standard Tiles

SuperMap iServer and iEdge support to read map tiles of the ZXY standard, in order to use OpenStreetMap and other Internet tile map services. The tiling rules for ZXY tiles are as follows: divide the map in full extent from the top left corner, from top to bottom and from right to left, into tiles of 256 * 256 pixels each. The upper left corner is numbered as line 0, column 0, and the number increases as it goes to the down and right directions. As shown below:

For ZXY map tiles, currently only the set of fixed map scales in the Web Mercator coordinate system is supported (PCS_WGS_1984_WORLD_MERCATOR, EPSG Code: 3857). As shown in Table 1, the zoom level of 0 includes one map tile of 256 * 256 covering the entire globe, and the origin coordinates are defined as (-20037508.34,20037508.34), that is the global upper left corner.

Table 1: Parameter List for Each Zoom Level of zxyTileImage Resource