Calculating gradient along a line using Points and Raster?

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03-23-2015 03:12 PM
ChristopherClark1
Occasional Contributor

Ok. I am not sure what the best route is to go about this.

I have collected line features (basically streams I walk along) and they have zvalues. So I have a set of lines...

I then made a set of points called Reach_Boundary. These are the up stream boundaries of a segment of the stream line. But they are just points. I have these points snapped right to the line. The upper boundary of segment 2 is the bottom boundary for 3, and so on up the line.. I also have a point file called Stream_Mouths that serve as the bottom boundary of the first stream line segment. This picture is an example of the data. THe line is the stream line with z information, and the points are segment boundaries. Notice on the far left point it is a brighter shade of Red, this is the stream mouth point, which is also the downstream boundary for the first segment. A segment is any portion between the lines..

StreamExample.png

I need to get a slope gradient for each segment. Should I first merge my point files, so the Stream_Mouth point and the Reach_boundary points are all in one feature class?

Then would I convert my line work into a raster, and use the points to extract values? My though is I could make a new column in the stream boundary point feature called Start_ELEV, and END_ELEV then create a new column called GRAD which would be populated by taking the (differrence between start Elev and End elev and dividing that by the length of the segment) (aka Rise/run).

Anyone think of a different way? Im brainstorming...

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ChristopherClark1
Occasional Contributor

Actually I have another Idea. Because I have all the associated other habitat data for these "segments" in a spreadsheet, I can actually just extract the elevation values for the points, then copy those into my spreadsheet and get the gradient figures from there....

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