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Graphing question (more fun with a GPSr)


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Yesterday, my father and I took the boat out on the local fjord, and spent three hours collecting 362 waypoints (lat., long., and depth of the water). I was hoping to bring this data into Excel, use it's ''surface'' chart tool, and end up with a map of the bottom of the fjord.


Unfortunately, Excel requires the X and Y coordinates (lat. and long., in this case), to be evenly spaced. They aren't.


Does anyone know of any freeware or low-price shareware that might be able to chart this data into a 3D topographical-type chart? The first five rows of data are here, if anyone wants to play with it.


Depth (ft) Longitude Latitude

-3.2808 -123.12745 47.42551

-9.8424 -123.12725 47.4255

-19.6848 -123.12717 47.42535

-39.3696 -123.12684 47.42523

-114.828 -123.12603 47.42516



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Are you looking for something that can coerce your data into a lattice for Excel, or something that will generate the pretty pictures directly? I once wrote some software that coerced the data into a lattice and then optionally generated the pretty pictures from the resulting lattice, but it was expensive and proprietary. I do have a (legally obtained) copy of that software, so if you just want a pretty (2D) picture or two I might be able to make that happen. I don't remember whether it was capable of re-exporting the gridded data or not; I think maybe it was.


The issue with just using the data as is rather than creating a lattice using some kind of interpolation is that outliers in your dataset can seriously mess with the resulting pretty pictures.



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Well I don't know of any cheap or freeware program to do this, However MathCAD does an excelent job of this. I was able to import and graph your data as a surface,contour,scatter or just about any other 3-D graph I wanted. If you want I could generate a graph for you if you sent me the whole data file, not as good as playing with it yourself but still something. I did a google and came up with this page showing a lot of cheap graphing software as well http://www.imagespro.com/programs/math/0-3.html if you explore those you may find a program that will do what you want

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Digital Grove's 'Surfer 8' demo did it for me -- thanks, BigBirdNL.


If you're curious, here's three of the maps that it generated from my batch of 359 waypoints (3 were bad):


Contour map:



3-D wireframe:



And a colored surface map:



Very cool. Thanks, all.



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