Hello, I just read this document http://geoportal.cuzk.cz/Dokumenty/Vyhlaska.pdf about terms of use. It says that the “viewing service” WMS is for free and you should just mention the source. There are some restrictions only if you would like to share the downloaded raster but there is no restriction for your own vectorized data. Other WMS layers from ČÚZK are officially used by OSM mappers and mentioned in the list of sources here: http://wiki.openstreetmap.org/wiki/Cs:Key:source#N.C4.9Bkter.C3.A9hodnoty.C4.8Dasto_pou.C5.BE.C3.ADvan.C3.A9v.C4.8Cesku I ask about it other Czech mappers and directly the ČÚZK office and will let you know.