Basically my problem is that one of my catchments refuses to have the stream line track the topography correctly. I am unsure why, the projection (WGS_1984_Equidistant_Conic) is the same as all the other catchments which have worked correctly. I'm using the flow path tracing tool included with Arc Hydro on Arc Gis 10 SP2on Window 7 64 bit. The flow direction grid was derived from 90m SRTM data.
I'm confident this isn't an error associated with poor DEM quality or bad DEM preparation, the error is systematic (typically tracking to the left or right of where the stream should be and often following a 'bad' path) for the length of the stream line which makes me believe it is something to do with the projection...but the lack of the same similar error among the other catchments doesn't support this. Perhaps the error occurs when calculating the flow direction grid, but again the lack of similar errors for any other stream lines in other catchments seems strange.
I've attached a screen grab of the error, as you can see the stream line is refusing to follow the topography...not sure what else to say apart from this.
I've created 100s of digital stream networks, long profiles etc before and I've never had this happen before. Any ideas? new projection? change file format? resample down to 30m and try again...anything before I break my laptop :mad:
Cheers,
Simon
