I hope a picture is worth a 1000 words.
In the cross-section image below, the cyan color shows the slice where the volume is computed for the range 0 to -1. Some of the volume is in areas of cut between 0 and -1 and others are in areas of larger cuts (as shown by the hatch pattern)
The red lines show the areas where the cut is within the specified range. The sum of these "red line" areas should equal the total cut area. The dimension shows the limits of where the actual cut is between 0 and -1. As you see, you can't relate the volume reported for that cut range with the area reported as they cover different areas.
If you want the volume of the cut in this slice that only comes from the area where the cut is between 0 and -1, you just need to take the total volume for that cut range and subtract the amount where the cut is larger than -1 (the hatched area in the image).
Luckily, it's simple to compute this volume as that volume will have a constant thickness (1m) so volume is just "Area * Thickness".
To get the area, just sum the reported areas for other cut ranges. (The "red" line areas)
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Gary Lantaff
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Original Message:
Sent: 07-28-2021 22:51
From: Fredrik Bergstrom
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Hi!
Thanks for your replay. Can you do a video when you do this and explains it, i rellay dont understand how this works.
I am using the define range to get the area from 0 to -1 and doing this by using the define ranges -2,-1,0,1 and 2. That should give med the correct area between zero and minus 1 i hope. otherwise i dont understand what this function is for.
It seems like the volume calculation is correct, its only the area wich is messing things up.
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Fredrik Bergstrom
Original Message:
Sent: 07-27-2021 14:56
From: Gary Lantaff
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
I think you are mixing areas that have a cut between 0 and 1 with areas that have cut more than 0.
The volume by depth range had a cut volume of 643m3 for the cut range of 0-1. That volume would include areas where the cut was more than 1m (but only include the volume from the 0-1 range). For example, think of a layered cake. Each cut range will have the volume of that horizontal slice but only the top slice would have any area defined (since all the "cut" depths are the same)
The surface info report includes the areas where the cut is in the defined range (so 549m2 in your case)
I think you can calculate the volume in the range from the numbers defined in the reports.
First compute area where cut is larger than 1m. You have two easy ways to do this.
1) Subtract area of 0-1 range from total area
areaAboveRange = totalArea - depthArea = (1016-549) = 467m2
2) Add up the areas from other depth ranges
areaAboveRange = 191+276 = 467m2
Then the difference should be volume where cut is only in the defined range. The thickness to use when calculating volume is 1m in this case.
volume= 643 - (467 * 1) = 176m3
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Gary Lantaff
Original Message:
Sent: 07-21-2021 22:24
From: Fredrik Bergstrom
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Ah, thats sounds correct and a problem wich i know exists. Volumes when its a island inside a island.
Contours at 0 and -1, thats how i used to do it but i was searching/hoping for a more easy and faster way to do it but it seems like i have to do it that way.
Thanks for all your help! 😁
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Fredrik Bergstrom
Original Message:
Sent: 07-21-2021 21:59
From: Marian Plucinski
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
You're right, it doesn't look right.
But I could not fault any of the functions using "Simple" models, I recon that multiple islands within islands are the reason.
I would recommend as follows:
Generate contours 0 and -1 on your CFM.
Create closed polygons.
Calculate volume and area within those polygons.
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Marian Plucinski
Original Message:
Sent: 07-21-2021 01:37
From: Fredrik Bergstrom
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Hi again, take a look at this video and file instead. I did a comparisation wich is correct when doing it with an easy surface but it does not look the same when doing it on my surfaces, any idea why?
Have a nice day!
https://www.dropbox.com/t/hzi8PNM7Ib2uYisg
http://somup.com/crirjwY0LW
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Fredrik Bergstrom
Original Message:
Sent: 07-18-2021 14:43
From: Marian Plucinski
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Hi @Fredrik Bergstrom,
I might be wrong, but I have a funny feeling that you're comparing volume of 0 to 1m CUT with the area of 0 to 1m FILL.
Any chance that you would share both your surfaces?
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Marian Plucinski
Original Message:
Sent: 07-15-2021 02:09
From: Fredrik Bergstrom
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Hi!
Thanks for your answers!
A stupid question, the ISOPACH surface and the C/F-map surface, is that not the same?
Here is a video of how i am doing it. :)
http://somup.com/crioQQYDmd
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Fredrik Bergstrom
Original Message:
Sent: 07-14-2021 15:46
From: Marian Plucinski
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Frederick,
I have never had a problem with Earthworks Report.
How are you calculating your Area By Depth?
You are looking at area by depth on the Cut/Fill Map surface, or is it ISOPATH surface?
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Marian Plucinski
Original Message:
Sent: 07-14-2021 01:03
From: Fredrik Bergstrom
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
That will not give me the correct volume, i dont really know how that function works but it gives me the wrong numbers. look at the picture below. As you can see i have only 479m2 surface (the picture above) wich is 1m or lower to excavate and if i do the same volume report as i did for the cut n fill and choose "by depth increasement" it will sa that i have 622m3 in volume. Thats more than 1m on that surface. So i need some other way.
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Fredrik Bergstrom
Original Message:
Sent: 07-14-2021 00:31
From: Marian Plucinski
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Surface -> Earthworks Report -> Volume Breakdown by depth Increment
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Marian Plucinski
Original Message:
Sent: 07-13-2021 23:20
From: Fredrik Bergstrom
Subject: Volume in specified depth area - ist it possible and if it ism how to do it?
Hi there!
I have a surface and i want to report this surface like this (the bold text i dont know how to do):
- Total volume - surface to surface
- What is the area where the excavation is 0 to 1m - surface area report of the isopach.
- The volume of the excavation 0-1m - i dont know how to do this in a easy way.
One way to do that volume calculation is to do create contours on the isopach on 0 elevation and -1m elevation and use thoose lines as boundarys in a volume calculation but that is a lot of work and i wonder if someone has a workflow wich is easier.
Have a nice day!
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Fredrik Bergstrom
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