topic Re: Intersect stream layer with another layer and preserve its flow direction? in ArcGIS Spatial Analyst Questions

Intersect stream layer with another layer and preserve its flow direction?

TungNg — Wed, 14 May 2014 23:30:22 GMT

Hi everyone,

I'm wondering if there is a way to intersect a stream segment layer (created by ArcHydro) with another layer (e.g. a grid) but preserve its flow direction (sample in fig. below). The reason for doing this is to get the correct flow order from upstream to downstream of different individual reaches so that these information can be used in cascading flow in hydrological models

When I used Intersect (Analysis) tool, stream segments were broken into reaches just fine but their orders were messed up

Any suggestion would be appreciated! Thanks!

Re: Intersect stream layer with another layer and preserve its flow direction?

DuncanHornby — Thu, 15 May 2014 10:15:23 GMT

Interesting to hear that the intersect tool ends up flipping the polyline direction. Well if your network contains no loops or bifurcations then you could use RivEX to re-orienate the vector network to a snapped mouth point. Have a look at the online help and search for the reorientation tool, make sure you understand the input requirements.

Re: Intersect stream layer with another layer and preserve its flow direction?

TungNg — Thu, 15 May 2014 16:24:47 GMT

Interesting to hear that the intersect tool ends up flipping the polyline direction. Well if your network contains no loops or bifurcations then you could use RivEX to re-orienate the vector network to a snapped mouth point. Have a look at the online help and search for the reorientation tool, make sure you understand the input requirements.

Thanks a lot for the reply! I'll check out RivEX later. Regarding "intersect tool", I don't really know how it works: longitudinal or latitudinal wise or something else. Would be great if someone here points it out for me

Cheers!

Re: Intersect stream layer with another layer and preserve its flow direction?

curtvprice — Thu, 15 May 2014 17:57:46 GMT

When I used Intersect (Analysis) tool, stream segments were broken into reaches just fine but their orders were messed up

Line direction is not preserved in overlay operations - if you want to re-orient your lines you need to create a geometric network to find the ones pointing in the wrong selection, and then flip the selected lines using editing or the Flip Line tool.

Re: Intersect stream layer with another layer and preserve its flow direction?

TungNg — Mon, 19 May 2014 15:16:53 GMT

Line direction is not preserved in overlay operations - if you want to re-orient your lines you need to create a geometric network to find the ones pointing in the wrong selection, and then flip the selected lines using editing or the Flip Line tool.

Thanks curtvprice! I've found out that ArcHydro also has Network Tools. One pretty good guide here. I'll give it a try and report back later