astridh

Interpolation of current flow data

Discussion created by astridh on Feb 5, 2013
Hello,

I have a dataset of current flow data (x,y,z), collected by a vessel-mounted ADCP over 11 transects, which were spaced by 300m. Normally I would use Matlab to post-process and interpolate these data. In Matlab I would apply the griddata function, which creates a uniform meshgrid (dimensions defined by myself) and applies linear interpolation, which I smooth at the end.

I would like to recreate the results in ArcGIS 10.0, but I am struggling a bit as I'm not entirely sure which interpolation to use.
Initially I thought the creation of TINs would come closest to what I've done in Matlab, but I think my data are not scattered enough (being formed by straight transect lines) and I'm ending up with a very jagged appearance and bad edge effects.
I then tried the natural neighbour interpolation and the result was closer to my Matlab results, but the surface was not very smooth. IDW gave ok results, but I would prefer the resulting surface to include the measured values. Hence I applied the Spline function, but it overestimated the values in some areas. Kriging at the end gave a reasonable good result.

I was now wondering if anyone here worked with current flow data and could give some advice on how to best interpolate these in ArcGIS. As far as I understand (please apologize if I'm wrong and correct if required) is a linear interpolation fairly simple and straight forward calculating the value of a point between two known points and thus differs from available interpolation options in ArcGIS, which are all distance weighted. Accordingly I'm hesitating to apply a distance weighted interpolation as I'm not entirely sure what the effect on my data will be.

Your help and advice is highly appreciated!

Best regards,
Astrid

Outcomes