Greyscale Analysis

We compare the greyscale, the desaturation and the smart background methods with the original maps and with each other. For this end, we not only analyse in details the resulting visualization, but we also conduct a survey. We asked a panel of people with cartographic training to evaluate the extent to which each method improves the readability of the original map and then to pick the most appropriate one.
The greyscale method renders the symbolisation less prominent and it is practical because simple to implement, but it has drawbacks. If there are too many colours in the original scheme, it become difficult to differentiate them on a greyscale. The same linear transformation is applied, no matter of the characteristics of the original colour schemes: there is no subtlety in this method. Two original colours differing in perceived brightness can be transformed into the same grey with this method.
True greyscale maps are specifically designed and not a mere transformation of a …show more content…
Depending on the value of this coefficient, the final result can closer to the greyscale or to the original colour scheme. The coefficient we chose here is 0.4 and gives satisfactory results with original bright colour schemes. The result with lighter original schemes (e.g. Map A) are satisfactory as well if it originally had contrast within its colour schemes. For both, it is still possible to clearly differentiate the classes of the initial colour schemes and it provides a better contrast with the foreground than original symbology. However combining the desaturation method with a relief background yields a very greyish and darker map background.The smart background method we develop here shows more promises. It has been tested and calibrated with colour schemes showing different characteristics: from already pastel tones to much darker and saturated colour