started project using longitude/latitude, want to change to utm

Discussion created by hendrix27 on Oct 27, 2011
Latest reply on Oct 27, 2011 by hendrix27
i started a project using aerial images and satelite data.
i have already identified serveral features (individual trees  and I georefernced historical images). all of them are in wgs 84 geographic coordinate system but i realised that i need a projection (e.g. UTM) since i want to put a grid layer of exactly 200m x 200m over the images.
so the best would be if i could transform all my data (a lot!) into utm zone 30, but when i do so via arc catalog, the coordiante system is not working any  more.
Any ideas? A working coordinate system is necessary because i will also do some ground truthing through gps.
any help is appreciated!