This article provides brief information about the process of map transformation in MapTiler Desktop and about map transformations in general. Map transformation determines the method of converting your picture into a map. This is done in MapTiler Desktop during the georeferencing stage after at least three control points are set.
The most suitable transformation method is set by default. However, you can always adjust this setting manually by clicking on the gear icon (top right) while assigning location visually (georeferencing).
There are five transformation methods available. They differ in the method of transforming your image as well as in a minimal number of assigned control points:
Scaled transformation combines rotation, scaling, and translation. It doesn’t change angles and shapes and also preserves parallels.
It requires a minimum of two control points to be set in a line.
Similarity transformation combines rotation, scaling, translation, and reflection. It doesn’t change angles and shapes and preserves parallels.
It also requires a minimum of two control points, but they don’t have to be set in a line.
The affine transformation is any transformation that preserves collinearity and ratios of distances.
It is a linear transformation that needs at least three control points.
Polynomial transformation calculates a polynomial equation that describes a curve crossing all of the control points.
TPS (Thin plate spline)
TPS transformation operates in three dimensions.
It requires multiple control points.