Abstract. Modern techniques for the map analysis allow for the creation of full or partial geometric reconstruction of its content. The projection P(ϕ k , λ k , ϕ 1 , λ 0 , κ) is described by the set of estimated constant values: transformed pole position [ϕ k , λ k ], standard parallel ϕ 1 , longitude λ 0 of the central meridian, and constant parameter κ. Analogously the analyzed map M (R , ∆X, ∆Y, α) is represented by its constant values: auxiliary sphere radius R , origin shifts ∆X, ∆Y , and angle of rotation α. Several new methods denoted as M6-M9 for the estimation of an unknown map projection and its parameters differing in the number of determined parameters, reliability, robustness, and convergence have been developed. However, their computational demands are similar. Instead of directly measuring the dissimilarity δ of two projections, the analyzed map M in an unknown projection and the image M of the sphere S 2 in the well-known (i.e., analyzed) projection P x are compared. Several distance functions for the similarity measurements based on the location as well as shape similarity approaches are proposed. An unconstrained global optimization problem poorly scaled, with large residuals, for the vector of unknown parameters x is solved by the hybrid BFGS method. To avoid a slower convergence rate for small residual problems, it has the ability to switch between first-and second-order methods. Such an analysis is beneficial and interesting for historic, old, or current maps without information about the projection. Its importance is primarily referred to refinement of spatial georeference for the medium-and small-scale maps, analysis of the knowledge about the former world, analysis of the incorrectly/inaccurately drawn regions, and appropriate cataloging of maps. The proposed algorithms have been implemented in the new version of the detectproj software.