AnsweredAssumed Answered

Stream Order

Question asked by eallan21 on Jan 8, 2016
Latest reply on Jan 8, 2016 by cdspatial

Hello. I am trying to create a layer that displays stream order but I'm having trouble. I have a stream layer with polylines. My stream layer does not contain any elevation or GPS start stop (node) information. I have a terrain layer with elevation data. I created a DEM with my terrain layer with terrain to raster. I then filled the DEM with Fill. Then I used Flow Direction with the filled elevation layer. At first I was following some other instructions and was created an Flow Accumulation layer and then using a conditional statement. Then I used Stream Order tool. This resulted in somewhat correct, but not actually correct stream order layer. First, the cell size of the stream order was too big so that my streams flowed out of one stream order value and into another at bends, etc. The stream order was also just not correct in some streams. I then made the cell size much smaller on all of the steps: Terrain to Raster, Fill, Flow Direction, Flow Accumulation, Stream Order. However, this resulted in a much worse stream order layer that was not accurate at all.


I also converted my stream layer to raster (Polyline to raster) but didn't know which feature to use (FID, Object ID, COMID, Date, resolution, Flow direction (1 or 0), name, length, type) so I used flow direction which resulted in a raster containing values of 0 and 1. Using this as the stream input for Stream Order Tool and using the filled Flow Direction for the flow direction input still did not give me an accurate stream order.


I then did the polyline to raster with smaller cells and used FID as my feature then created a conditional statement to say that everything with a value is 1 and everything with no value (nothing) is 0. This created a raster that outlined my streams pretty well.


However, again when I try to calculate stream order with this stream raster and with the small cell size filled flow direction, the stream order is completely wrong. A first order stream segment may start as 1st, change to 2nd, change back to 1st, change to 3rd, change back to 1st, etc.


Can anyone offer me some help?