topic Re: Points along a polyline with equal total line lengths between points in ArcGIS Pro Questions

Points along a polyline with equal total line lengths between points

AttA — Wed, 22 Jan 2025 10:11:10 GMT

Hi everyone,

I'm working with a stream represented as a braided polyline. My goal is to place points along the stream such that the total length of the polyline segments between consecutive points is constant.

The stream's braided nature means the polyline isn't always a single straight line, and the segments can have varying orientations and curvatures (see screenshot).

I'm looking for advice or methods to achieve this. Any suggestions or insights would be greatly appreciated!

Thanks in advance!

Re: Points along a polyline with equal total line lengths between points

DanPatterson — Wed, 22 Jan 2025 11:09:09 GMT

Generate Points Along Lines (Data Management)—ArcGIS Pro | Documentation

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

So generate the points that you want to use, then split the polyline.

You can't actually make all the points of a polyline equally spaced otherwise you would have a straight line since each deviation in angle necessitates a point, and segments make up the polyline.

Re: Points along a polyline with equal total line lengths between points

AttA — Wed, 22 Jan 2025 14:31:52 GMT

Dear Dan,

Thank you very much for your reply!

I realise my visual example was not the best: what I meant to achieve is to have points (not necessarily equally spaced) that would include a portion of my stream that sums up to the same length. I would assume two points would be closed to each other if the stream section in between is highly braided and further from each other if the stream section is straight.

What I achieve now using "generate points along line" is really weird, as I get exaclty the opposite (closer points on straight portions of the stream).

I am also not sure if I should merge all segments into one before running any tool.

Thank you again!

Re: Points along a polyline with equal total line lengths between points

DanPatterson — Wed, 22 Jan 2025 17:49:09 GMT

buffer the braided stream by a distance to collapse the braided streams (use the dissolve all features option )

Buffer (Analysis)—ArcGIS Pro | Documentation

You should now have a buffer without any interior holes (hopefully)

Ifffff you have the Topographic Production extention, then you could use

Polygon To Centerline (Topographic Production)—ArcGIS Pro | Documentation

but assuming you don't, then you could reverse the buffer using a negative distance which "might" yield a single skinny polygon.

Other options would be conversion to raster after a negative buffer, then thinning the raster and conversion to polyline if you want a line rather than a polygon.

Thin (Spatial Analyst)—ArcGIS Pro | Documentation

There are many other options, but you will not a a one-shot tool that will do what you want for all stream braiding patterns

Re: Points along a polyline with equal total line lengths between points

AttA — Tue, 28 Jan 2025 11:17:00 GMT

Dear Dan,

Thank you very much for the help!!