Code to generate artificial species and observer model

The artificial species is generated in real environment in Germany. The species favours the South of Germany (more mountainous), but probability of non-detection increases with the altitude which truncates the Southern distribution of the species.
See: Manceur, A. M. and Kühn,, I. 2014. Inferring model-based probability of occurrence from preferentially sampled data with uncertain absences using expert knowledge. Meth. Ecol Evo. DOI: 10.1111/2041-210X.12224