Ascii to Raster Projection problems!

[MaggieTriska]

I've obtained solar radiation data in an Ascii format and have been able to create a rastor in arcmap, but my issue is with the projection. I have specific sites that I want to extract radation data for. Anyways, the header of the ascii file contains x/y centers, but the company says I can use the data in any projection I want...I'm not sure how to do this. Do I need to change the values in the header (as of now its not supposed to have any spatial reference "undefined" but there are values in it) and if so how do I know what values to put in???? For exapmle XY coordinates of my ascii are roughly 110,-43 and the actual xy values should be around 6000000,400000.

[MaggieTriska]

Problem solved -

[DieterMayr]

HI M_Dakota and everyone else!

I have a similar challenge with my data: I got many data file for Solar radiation (hourly data for 10 years, in kWh per m²) in asc format. Furthermore I have polygon layer, which represents the available roof areas, for which I would like to calculate the solar potential.

My tasks are right now:
1) i need define a spatial reference for all data, which is easy possible with a batch.
2) I need to "combine"/calculate the raster information (radiation) for each polygon (roof area) for ALL ~ 20.000 datafiles. Does anybody has experience with this kind of task and might explain me how to proceed? Is it really necessary to use ArcMap for this or is there any better possiblity?

Thanky for every kind of help!!
Didi