openlayers 3 how to get map scale using zoom level

Question

is there a way to get the map scale on openlayers 3 the map change zoom level ?

i found a site that converts from map distance to scale

zoomlevel : 20 to map scale : 1:50000.

https://www.maptools.com/scale_calculator

is there a way in openlayers to get the map scale using the zoom level as map distance

Answer 1

The easy thing you can do is to display a scale line, as demonstrated in this example.

var scaleLineControl = new ol.control.ScaleLine();

Computing a correct fractional scale is quite complicated, because you would have to take into account the resolution of your screen, which of course differs from one device to another. This control did exist for OpenLayers 2.

Answer 2

As far as I know, it doesn´t exist something like this, you can have a scale bar that tells you based on the width of the bar how much it corresponds on the map.

Please check the example in OpenLayers4 and the tutorial for OL3

https://openlayers.org/en/latest/examples/scale-line.html

http://student.ifip.tuwien.ac.at/geoweb/2013/ol_workshop/doc/controls/scaleline.html