* double click on the province will show all district of this province and zoom center to fit as best
* the "prefecture division level" will be show according to the zoom factor
* click on the district will zoom and center to fit as best
* the cave layer is always on the top of the layers
* click on the cave will open a popup with a link to the detailed cave data
* zoom with wheel + cmd or alt is from 1 to 300
* on the top left infos are displayed (Province, County, Cave name)
* on the top left coordinates (dd) are displayed following the mouse ...
* the meridiens and parallels are displayed with a frequence from 20° to 1° according with the zoom factor...