Color stream segments by attributes (assigned and extrapolated)?

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03-29-2011 01:51 PM
danielfenner
New Contributor
I have multiple samples along a stream segment (pulled from NHD) from which I'd like to extrapolate to create a gradual color scheme of a single stream.  For example, say I'd like to color code the stream by temperature measurements, in which red colors would represent relatively high temperatures and have a gradual progression of colors down to blue, representing low temps.  I'm assuming a similar analysis has been done, but I don't know what to search for in the forums because I'm not sure of the correct terminology for such an analysis. 

More specifically, is there a way to evenly divide up stream segments and assign a value (temperature in this example) automatically?  Is there a tool that will assign values to stream segments by extrapolating between line segments which have an assigned value (temperature in my example).  I'm thinking something similar to creating contours in a raster, but for a single line instead. 

Any suggestions would be much appreciated! 

Daniel
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847396730
Occasional Contributor III
Does each segment in your stream have an attribute field indicating its temperature?
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danielfenner
New Contributor
Thanks for your response!  I didn't get it until today because I thought I would receive an email if someone responded to my post..I didn't.  Will have to check my settings.

No, each segment does not have an assigned temperature.  Only those segments where the temperature was actually collected has an assigned temperature.  I was hoping that I could sort each segment in the attribute table by flow direction (or distance from the confluence, for example) and manually (likely using excel) fill in the missing data by extrapolation.  However, after creating even stream segments (using xtools - split polylines) the data cannot be arranged according to flow direction or distance from some stream point.  Therefor, I can't manually extrapolate values using the attributed table.

I've moved in another direction, using raster interpolation; however, I'm having problems with that as well.  Because of the many meanders in the streams I'm working on, a Natural Neighbor analysis is making calculations of points that are close to each other in straight linear distance, but not close to each other in stream distance.  I was hoping I could use analysis 'barriers' with the interpolation analysis (IDW, Kriging, or Natural Neighbor), but I don't see that option. Right now I'm stuck until I can get this resolved.

So, I'm open to resolving this issue by either approach mentioned above!
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