irregular areas

Do you have a digital surface built yet?

negatory. is there an app for that?

Create a TIN.

What Wendell said....;-)

average length times average width times average height equals volume.

Andy - I would try using the average end area computation: "the volume between cross sections is approximately equal to the average of the two end areas multiplied by the distance between them."

The more cross sections used, the more accurate the end result.

Tim

What CAD are you running? I am assuming that whatever it is has topo capabilities.
You should just be able to develop a surface for the pile and a surface for the ground and generate a volume report between the two.

The best way is to create a surface model as has been suggested and let cad do the heavy lifting. The other method I have used plenty of times on piles of dirt, sand, gravel, etc. is cone volume and a touch of dead reckoning. If the top of the cone was flat I might take off 10% volume, for example.

have never created a TIN in real life. Florida is FLAT... like the top of this his is 60' above sea level, I thought I was going to run out of oxygen. So, while i understand the concepts you all are mentioning, I have no clue how to ACTUALLY do that.

Andy,

Are you looking for area or volume?

Area is simple, just turn your delineation of the bottom of each pile into a polyline and check the properties for area.

Volumes require a bit more work. If you are looking for something really rough you could multiply the average height by the area of the bottom of pile and by the area of the top of pile. Subtract the top of pile volume from the bottom of pile volume and divide be two. The add that to the top of pile volume. This is really rough and makes a lot of generalization of the pile but it will give you an idea of what you are working with.

The best results are derived from creating a TIN representing the surface of the bottom of the pile and the pile its self. Then run any number of volume routines in your survey software.

Do you have some version of CAD that can calculate volumes between two surfaces? This would take me about 10 minutes.. just send me the data! 😉
Does the contractor want to know tonnage? Or will cubic yards be sufficient?

I was supposed to do one of those last month, but they hired an engineering firm instead. It was for 6 piles of crushed material.

I'm like you in that I can do it the old fashioned way, but don't have the software to do it the newfangled way. So I had a very qualified CAD guru who works for a large engineering firm (with his own software) lined up to calc it. It would take him 20 minutes to do what would have taken me 4 hours, and likely his numbers would be more accurate.

The key is to get enough shots to define the surface of the pile, and the base elevation of existing ground. It's two different surfaces that must be defined, then press the button and a volume majically is calculated. Then make a nice map to show the areas and general shapes.

Maybe I'll get the next one. Good luck Andy

> not too fancy, just a general idea of how much rock he has

Remember that in many cases, "ball park" number becomes "gospel" number when you let a quantity out the door. Numbers travel, the next recipient may not know that this number is just a general idea of how much rock he has.

Let them do their expansion/reduction factors too.

There's a lot of money in rocks, be careful.

- - - - -

As the others mentioned, two surfaces, base (perimeter of pile) and pile (perimeter of pile + pile itself).

As checks:

-Create an arbitrary alignment, cross-sections and run AEA's volumes.
-Check the area at the base, area at the top, average height of pile, confirm that your number makes sense.

Some software manufacturers also have stockpile volume utility. Useful.

Andy, I've got a great idea...

Post your ascii file, pdf, dwg or something and let us all play with it. Then take the average of what everybody comes up with.

I had the honor for eight years of employment of measuring stockpiles at two asphalt plants EVERY month. I have figured piles with hundreds of shots and figured piles with twenty shots, both long hand and with cad surfaces and compared them at times. I found usually less than a 10% difference in the quantities.

As long as you qualify with a plus or minus statement the quantity you give the client, you should be able to keep you butt out of a wringer.

Send the 3d points to me, I do em all the time. I assume they didn't give you a conversion factor from cubic yards to tons. Better to let them do that, everybodies got a different number.

Like Paden, I've had to measure piles at 4 different asphalt plants and a couple of limestone quarries monthly or quarterly over the past 34 years. PITA

okay, made two surfaces from the points. one of the perimeter and one of the whole pile. I'm in autocad 2000. LDD ??

Break it into several horizontal slices through the pile where the pile makes sudden changes. Figure areas for each slice. Then sum the bottom area and the first slice up. Divide by two for average area. Multiply by height between slices to get volume in that part of the pile. Repeat process between next two slices until you have the top slice and zero area for top of pile. Sum the volumes.

Many years ago we used a similar process creating vertical slices to determine compacted volume of dirt required to construct pond and lake dams.

Send me an ascii text file with your shots (PNEZD) & I will give it a go.

ott at mainstreetconsulting dot com

I sent the point files to Randy... thanks for all the offers of help.