From 1958 to 1964 he was employed in Graz as an official of the Federal Office of Metrology and Surveying (Bundesamt für Eich- und Vermessungswesen, BEV).
He studied publications by the mathematicians and cyberneticists Norbert Wiener and Andrei Nikolayevich Kolmogorov, and expanded his academic teaching in theoretical geodesy.
This was later reflected in the book Physical Geodesy, co-authored with Heiskanen; this work was translated from English into Chinese, Serbo-Croatian, Spanish, and Turkish and became a geodetic bestseller.
Here he continued his work on the geodetic boundary value problem of the great Russian geodesist Mikhail Molodenskii for the determination of the Earth's shape from measurements of gravity and gravitational potential.
During his time in Graz, Moritz compiled and carefully structured the mathematical and statistical foundation of collocation in all its facets in his fundamental book Advanced Physical Geodesy (1980).
And finally, a strong international demand for a revised new edition of his fundamental early book Physical Geodesy, now jointly with B. Hofmann-Wellenhof, closed the circle of his scientific volumes.
He spoke several foreign languages: English, French, Italian, Polish, Russian, Serbian, Croatian, Slovenian, Spanish, and Czech.
He became chairman of a study group of the International Association of Geodesy (IAG) on fundamental Earth constants, which have not only geodetic but also astronomical, geophysical, and geographical significance.