Earthwork Calculation

[clarksbuddy-dis]

I am trying to use cspline to perform an earthwork calculation on a 115 acre site from which I have taken 100 spot elevations, a very rough data set admittedly. The attached follows a previous post by Giraud. I stopped short of performiing an integration of the surface generated by the interp because I was not sure how to interpret the results; how to relate the scale to the actual data, i.e., the xy grid. Further, when I generated a mesh using CreateMesh, I get a gruesome figure.

[RichardJ]

No data file

Richard

[ptc-1368288]

On 4/8/2010 10:16:24 AM, clarksbuddy wrote:
>I am trying to use cspline to
>perform an earthwork
>calculation ...
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Please, attach the data set in Mathcad version 11.
It sounds feasible, easy.


jmG

[clarksbuddy-dis]

Sorry about that...Here is a revised worksheet.

[clarksbuddy-dis]

The file did not attach...try again

[ptc-1368288]

On 4/10/2010 10:02:44 PM, clarksbuddy wrote:
>The file did not attach...try again
_________________________

OK for the file.

Not sure why you need Mx, My if you plot only the Mz level matrix. Mz is square and that makes the project much easier, you can then "metric" the square as you wish. At this point, you seem interested in the volume under the surface plot and above a certain datum plane. I have recollection that such a project was done in the collab, Richard might have it in hand. I have it too but need a bit of search. Hope collabs can help. A datum plane 0 has been added for the demo and complementary comments back from you.

jmG

[AlvaroDíaz]

You're trying to interpolate from scatered 3d data. There are not a standard mathcad procedure to do this. In the attached, matlab component is used.

Regards. Alvaro.

[ptc-1368288]

"...using spot elevations taken from 2007 aerial photographs."
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The "Spot" mountain looks reasonable to a flying bird. My interpretation of "Spot" is now that 10 slices of that mountain can be extracted and plotted by slice. I have no problem from the Matlab replot after feeding in Mathcad. If you can code it, would be better for traceability.

jmG

[TomGutman]

Your data is not on a regular grid. Your conversion of the data vectors to matrices is completely incorrect. You need some form of resampling (interpolation) based on the data vectors before you can create meaningful matrices. Chances are once you have a resampling procedure, it will provide all the interpolation you need and leave no need for cspline.
__________________
� � � � Tom Gutman

[ptc-1368288]

On 4/11/2010 7:48:42 PM, Tom_Gutman wrote:
>Your data is not on a regular
>grid. Your conversion of the
>data vectors to matrices is
>completely incorrect. You
>need some form of resampling
>(interpolation) based on the
>data vectors before you can
>create meaningful matrices.
>Chances are once you have a
>resampling procedure, it will
>provide all the interpolation
>you need and leave no need for
>cspline.
>__________________
>� � � � Tom Gutman
_________________________________

Agreed 100%, well explained. The problem is the number of slices of that mountain. I just replied 10 slices as a guess. It might very well be only one slice of levels Spot<2> and the task is to resample on a regular XY grid. The 3 vectors "Spot" are machine tool style decades ago.

jmG

[ptc-1368288]

I will leave this thread with my verdict:
The 'y' matrix DOES NOT represent any possible plane. This column vector is definitively WRONG. It's one of so many pieces of information from so many images fabricated for unknown. An 'y' plane can be a bit bizarre, especially if it comes from a function [breather is a good example]. But this one is only a level vector. So, the project is back to square 0, to be done from a data set that is representative.
The first example is all correct.
The Shoreline is scrap, as simple as that.

jmG

[clarksbuddy-dis]

Sorry for the belated response. I have been out of town on another project. Thank you for your responses.

Tom G's suggestion that the existing conditions be plotted on a rectangular grid and then interpolated points to my original problem. I have no current accurate data. The data I used was estimated from old topos. I was looking for a "quick" analysis that could give me a reasonable estimate of a revised grade on the floor of the mine. I'll try again. Thanks.

[ptc-1368288]

On 4/28/2010 4:52:50 PM, clarksbuddy wrote:

...

> The data I used was estimated from

>old topos. I was looking for a

>"quick" analysis that could

>give me a reasonable estimate

>of a revised grade on the

>floor of the mine. I'll try

>again. Thanks.

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Your description here and in your original sheet does not print in my mind. What are these data ? Do you think old aerial photos can give 15 decimals ? I don't think so. A data set should NEVER EVER come from an Excel sheet as you have, and that I made compatible to Mathcad. Your data "Spot" plots the "massif" and the diagonal interpolant plots the level on grid and on "mesh that you can metric" at will. That's about as far as your project goes up until now. jmG