topic Re: Counting Pixels Along A Stream in ArcGIS Pro Questions

Counting Pixels Along A Stream

SethLewis2 — Fri, 04 Jun 2021 19:15:27 GMT

Hi all-

I'm looking for a tool that will count pixels along a stream. I have a TIF file which displays binary pixels (either 100 or 101) that follow a stream. (A bit of background - I'm assessing a model that identifies areas along streams that could benefit from increased riparian planting. The TIF file is a product of the model, giving me pixels that either meet or fail certain criteria: % solar gain and canopy cover, mostly.) Is there a tool that could count the number of pixels up/down a stream for a specified distance?

Thanks so much for any and all tips.

Re: Counting Pixels Along A Stream

JayantaPoddar — Fri, 04 Jun 2021 19:23:08 GMT

How about creating a buffer on the stream layer with prerequisite distance, and then executing Zonal Histogram.

Re: Counting Pixels Along A Stream

SethLewis2 — Fri, 04 Jun 2021 20:14:04 GMT

Thanks for the tip, but unfortunately a buffer wouldn't work because it would include neighboring streams and their pixels as well (I need about 600 meters of stream reach analyzed). Is there a way to create an elongated buffer that would follow the stream and therefore not be a perfect circle?

Re: Counting Pixels Along A Stream

JayantaPoddar — Fri, 04 Jun 2021 21:56:41 GMT

Buffer on lines are never circular, its end could be rounded or flat (as per your choice). Is it possible to select the stream stretch, and then execute Buffer?

That brings another question. Do you have streams as lines or only as raster? In case you have the streams as raster, you may need to do an additional step of Stream to Feature or Raster to polyline.

Re: Counting Pixels Along A Stream

DanPatterson — Fri, 04 Jun 2021 22:07:49 GMT

convert the raster to vector

split the line at your point of interest

Split Line at Point (Data Management)—ArcGIS Pro | Documentation

Select the line of interest, then in an Edit session

Divide a polyline by a value—ArcGIS Pro | Documentation

you can specify the distance(s) to subdivide the line along and whether to start at the end or beginning of the line.

I only suggest this is that it allows you to fine-tune your analysis horizon along the stream reach, because I am sure you will want to fiddle with the distance values at some stage.

Re: Counting Pixels Along A Stream

Mary_Murphy — Fri, 11 Jun 2021 08:14:09 GMT

Vector based approach:
This article [but undertaken in Pro!] might help :https://support.esri.com/en/technical-article/000012696