I'm having trouble understanding the meaning of the concept of scale when it comes to maps on screen, i.e. either in a Desktop GIS or in a WebMap.
When it comes to paper maps, the idea is very clear. The Scale is the ratio of a particular distance on the map, to the same distance on the ground.
But when it comes to maps on screen, the same concept cannot be applied. Firstly different screens do not have the same pixel size. It might be that a 14 inch monitor and a 24 inch monitor could have the same resolution (in terms of pixels). Then comes the issue of dpi. An iOS device with retina display has a dpi several times that of my work-station monitor. So 1 cm on my screen might show a different distance than 1 cm on your screen.
So what does the scale of a map in digital cartography mean? What does it mean, when I see the scale of a map is 1:180,000 in ArcMap?
This question came about because of several ArcMap Documents I received from a client who publishes paper maps.
The paper map is published at 1:180,000, but at that scale the map looks terrible. It's only when I zoom in, does the map look good. With trial and error, I found that the map looks best on screen at about 3 times the scale, i.e. at 1:60,000