Hi Jonathan Penuliar
Thank you so much ,that was a big point which I missed . I have still some problems with Zoom value and I have a question, what does the expression do? why I cant use my Longitude and Latitude which I gave from GPS or Google map straightly?
You're current zoom level is Max =17, try a little lower.
I you have 1 selected kanal, Chart will zoom in the map to that location, selecting multiple kanals can be tricky as it the map will try to show all locations in the map. So if you have locations which are all across the globe, map will zoom out to max level.
Try to assign _zoom_level to a listbox and play with the values.