I'm new to GRASS. We want to delineate a watershed using the LIDAR data we have our hands on. I tried to follow several procedures to do so, but despite all my efforts, I can only get it to select a single cell out of the DEM.
I'm using GRASS 7.0.5
What I've done:
- Created the DEM using r.patch and the necessary tiles
- Defined my work region (g.region)
- r.patch the DEM to fix the bridges
- Used r.watershed to create the Accumulation and Drainage direction layers (tried with 0, 5k and 50k thresholds)
- Used the Drainage layer to r.water.outlet
While I eventually get a result, it is only a single pixel, although I made sure to be very (VERY) precise (5 digits precise...) on the stream coordinates. Picture of the output.
I believe part of the problem is that my DEM is huge... but I find it hard to believe that I'm the only one using this kind of data.