Writing this happy-birthday message made us think of some of our past contacts with Irwin and his software AirPhoto.

When Irwin arrived in Germany, the Cold War had already enveloped Central Europe in the Iron Curtain. Little could he expect that its remnants would be chasing him well into the 21st century. In 1960’s the Soviets’ growing paranoia to protect parameters of the Pulkovo-1942 grid system (a paranoia caused amongst many factors by the development of the Keyhole satellite surveillance programme and GPS) forced the Eastern Bloc to withdraw it from the civilian use. Instead countries of the Warsaw Pact were obliged to introduce separate coordinate systems and so the most peculiar CS-1965 was born in Poland. The entire country was divided into five irregular zones which used two different projections and false eastings and northings in each zone. Furthermore, the grids were not concordant and it was impossible to combine maps along zone boundaries. In practice it meant an introduction of five separate grid systems (see diagram – Poland’s division into five zones (“Strefa”) in CS-1965).

Although the state-of-the-art system CS-1992 was implemented after the fall of communism, CS-1965 provided a full coverage for the country and for more remote areas it is still the only set of maps at 1: 10 000. This turned out important when we started extensive aerial reconnaissance in Poland. To be able to rectify oblique aerial photographs there was no other option but to ask Irwin to add CS-1965 in AirPhoto. In Spring 2007 after little over a month of email exchanges about ellipsoids, projections and datum, frantic digs for parameters in various institutions and learning how to answer Irwin’s questions, he could announce a successful implementation of the system which despite its peculiarities proved fully functional.

Four years later Irwin’s attempts to improve some tools prompted us to inform him that we were just witnessing the very end of CS-1965. At that time topographic maps were converted from CS-1965 into CS-1992 and full sets of maps were made available via geoportal. To this information only one answer could come:

Subject: S65 Strefa Boundaries
Date: 2011-01-26 09:14
From: Irwin Scollar <al001@uni-koeln.de>
I’m sure that everyone will be pleased to see the end of CS-1965! I certainly will be among them. It caused me more work than any other of the 50 grid systems supported in AirPhoto. 

With best wishes to Irwin on his 90th birthday from the Polish aerial team.