A. Set map zoom level in Zoom dialog box
Click menu item "View->Zoom->Zoom"
Zoom dialog box will pop up:
B.Directly click on menu item to set zoom level
Click menu item "View->Zoom->Zoom in" ：
Each click will increase zoom level 10%.
Click menu item "View->Zoom->Zoom out"：
Each click will decrease zoom level 10%.
Click menu item "View->Zoom->Fit map"：
Mindv will calculate an appropriate zoom level so that all of the topics can be displayed in the window.
C. Use the slide bar in bottom status bar to select an appropriate zoom level.
