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Calculate the volumes of cut and fill between two DTMs |
Cut and Fill Volumes
To access this dialog:
Introduction
This dialog is used to facilitate the modeling and evaluation of cut and fill volumes, based on original and updated wireframe surfaces (DTMs).
The input to this command will be two DTM surfaces, commonly representing the progression of a digital terrain model in time. You can select a surface from any loaded wireframe surfaces.
This function will calculate:
- Volumes that have been planned but not mined
- Volumes that have been mined and not planned
- (Optionally) volumes that were planned and mined
Selecting Wireframe Data
By default cut and fill volumes are calculated within the common area covered by the two input surfaces.
A supplied cut attribute field is used for the assignment of the cut and fill volumes. The user therefore supplies the name of this new (numeric) field, and what values will be assigned within 'cut' blocks and 'filled' blocks. This enables clear identification of cut and fill volumes, for both evaluation and plotting/display purposes. Setting these values is optional, but recommended. For example, an attribute in the 1st (earlier in time) and 2nd wireframe surfaces could both contain a MONTH attribute and 12 unique values. You can then pick the same Keyfield for both surfaces, but a different Value (e.g. [MAY] and [JUNE] - this will allow these values to be assigned to the appropriate cut and fill volumes that are generated between the surfaces.
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You can use the same Keyfield attribute for both wireframe surfaces if you wish, but you cannot assign the same Keyfield & Value pair combination to both surfaces (this would make it impossible to distinguish cut and fill volumes. |
Existing/displayed wireframe surfaces can be selected interactively,
and you can optionally elect to verify the input wireframes. This is recommended,
and is the default setting.
Using Outlines
Selection of one or more outlines will further restrict the area to the overlap of the common boundary and the selected outlines.
The cut and fill volumes can optionally be calculated within one or more defined boundaries. If no outlines are specified the volumes are calculated within the complete common area covered by both input surfaces. Selection of one or more outlines will further restrict the area to the overlap of the common boundary and the selected outlines.
Calculating Volumes Within Benches
You can also calculate cut and fill volumes within benches by manually specifying a pattern of bench heights within your pit. A read-only summary of bench information is displayed.
Evaluating Volumes against a Model
The cut and fill solid volumes can optionally be evaluated against a block model. You can select any model on disk, then the appropriate evaluation keyfield and evaluation legend.
If you choose to calculate a table containing the evaluated volume details,
you can choose the output file name using the Outputs
group at the bottom of the table.
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The Cut and Fill Volumes dialog can be left in view whilst you continue to work in other areas of your application, providing a cut and fill calculation is not in progress. |
Field Details:
The Cut and Fill Volumes dialog contains the following fields:
Initial or First (Earlier) surface: select the loaded DTM that represents the first surface. You can either do this using the drop-down list, or the data picker button on the right, if the required surface is displayed in the 3D window. The input surfaces should be open surfaces, but each input can contain more that one open surface.
The default Keyfield is <None>. If you select a key field the Value drop down list is populated with unique values (up to a maximum of 50 values).
If the Verify button is checked then a check is run on the input surface to ensure it is a DTM (Digital Terrain Model).
Planned or Second (Later) Surface: select the second surface using similar controls to the first (see above). The second surface can be the same as the first surface if a different key field and value pair is selected. If a key field and value is selected for the first surface then the second surface can be the same as the first, but the same key field/value pair cannot be chosen.
If the Verify button is checked then the wireframe-verify function is run on the input surface – taking account of any key field / value pair.
Actual or
Reference Surface:
Disabled by default, if an actual/reference surface is specified, the output
volumes and report will include the data between the reference and first/second
surfaces.
When you run the calculation with actual or reference surface, it will compute the volumes between the reference surface and the first and second surfaces. A typical usage would be to have the reference surface set to your previous mined surface, the first surface set to your planned surface, and the second surface set to your current mined surface.
If an Actual or Reference Surface is specified, the results shown will ithe following information:
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Total common volume (planned and mined)
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Total first only volume (planned but not mined)
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Total second only volume (mined but not planned)
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Total outside volume (planned or mined but in a different area)
Additional Table Data if an Actual or Reference Surface is Specified
When using a reference surface the following additional column is added to the output solids and outlines:
REGION - This column identifies where the volume lies with respect to the input surfaces. It can have the following values:
1 - The volume lies between the reference surface and only the first surface and is outside the second surface boundary (coloured grey)
2 - The volume lies between the reference surface and only the first surface and is inside the second surface boundary (coloured green for above second surface, red for below second surface)
3 - The volume lies between the reference surface and only the second surface and is outside the first surface boundary (coloured grey)
4 - The volume lies between the reference surface and only the second surface and is inside the first surface boundary (coloured green for below first surface, red for above first surface)
5 - The volume lies between the reference surface and both the first and second surfaces (coloured cyan)
When using a reference surface the following additional columns are added to the output result table:
CVOL1OUT - The cut volume that lies between the reference surface and only the first surface and is outside the second surface boundary
CVOL1IN - The cut volume that lies between the reference surface and only the first surface and is inside the second surface boundary
CVOL2OUT - The cut volume that lies between the reference surface and only the second surface and is outside the first surface boundary
CVOL2IN - The cut volume that lies between the reference surface and only the second surface and is inside the first surface boundary
CVOL12 - The cut volume that lies between the reference surface and both the first and second surfaces
FVOL1OUT - The fill volume that lies between the reference surface and only the first surface and is outside the second surface boundary
FVOL1IN - The fill volume that lies between the reference surface and only the first surface and is inside the second surface boundary
FVOL2OUT - The fill volume that lies between the reference surface and only the second surface and is outside the first surface boundary
FVOL2IN - The fill volume that lies between the reference surface and only the second surface and is inside the first surface boundary
FVOL12 - The fill volume that lies between the reference surface and both the first and second surfaces
Decimate each input surface to limit....: select this option to make sure that any generated surface does not include more than a specified number of triangles. Triangles are removed by decimation.
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This option is enabled by default, and if disabled, you will be alerted that memory issues may occur without decimation. A recommended target is provided. |
Outlines
If no outlines are selected the volumes are calculated within the complete
common area covered by both input surfaces. Selection of one or more outlines
will further restrict the area to the overlap of the common boundary and
the selected outlines. Alternatively, you can choose an existing outline
object.
Use selected strings: You can utilize previously selected outlines (or you can select them with the dialog still open)
Object selection: as an alternative to the above, you can nominate a loaded strings object by selecting it from the drop-down list or using the Data Picker button to select an on-screen string object.
Keyfield/Value: You can also select an optional key field. If a Keyfield is specified (by <none> is selected so all values will be used) cut and fill volumes will be calculated within all valid perimeters. If a key field value is selected then only valid perimeters with that key field value are used.
Test
for overlaps: this button allows you to check to see if any of
the string entities within the selected object are overlapping, producing
ambiguous areas.
General rules for using outlines in this command:
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Only closed strings – perimeters - are permitted.
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Strings must not have crossovers.
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For a perimeter to be valid its area must be completely filled with triangles from each of the input surfaces.
The presence of invalid strings will not terminate the process but they will not contribute to the results and their key field values will not appear in the results table.
If an outlines object has been specified and this option is enabled, and no valid perimeters are found then the process is terminated and an error message is displayed.
Benches
Cut and fill volumes can be optionally calculated within benches.
Calculate volumes with benches: enable this option to activate the remainder of the sub-tab. Benches are only considered in this check box is enabled.
Manual: the grid can also be filled out manually by firstly defining the uppermost Crest elevation, then a number (No. of benches) of contiguous benches of the specified height (Bench height).
Click Apply to add rows to the grid - note that once the first set of benches has been defined, subsequently-added benches will be added to the bottom of the table (in reducing elevation order). This allows you to repeatedly set bench definitions within the table following a top-down approach. Once the first set of benches has been added to the table, the Crest Elevation value is disabled.
If you wish to reset the initial Crest elevation, it is necessary to Clear the grid. In this situation, the Crest elevation field becomes editable.
Once populated, the bench table contains the following information, per bench:
Label: an index label for the defined bench
Height: the height of the bench
Crest Elevation: the crest elevation of the bench
Toe Elevation: the toe elevation of the bench. For contiguous benches, this will equal the Crest Elevation of the next bench in order.
Whichever method is used, the bench height can be negative if the start elevation is at the top of the volume being considered.
Grid settings are automatically saved and can be retrieved in subsequent sessions (with the same project) using the Restore button (see below).
Evaluation
The cut and fill solid volumes can optionally be evaluated against a block model.
Manually select a model: as an alternative to the above, a model file can be selected from a list of loaded objects, or from disk.
Density: the DENSITY field will automatically be selected if it is found, but you can select any numeric attribute within the model file, and specify the default value to be used where a density value is not found.
Legend: the evaluation legend to be used must be selected. If a unique value or range legend type is selected then a Column must also be selected (this isn't required for filter legends).
You can also use the standard legend toolset to create a default legend for the selected column, edit the legend using the Legends Manager and/or display a summary key of the currently selected legend.
Outputs
The following data can be output from this command:
Summary file: this table is always created. Once a cut and fill scenario has been defined, a summary file is created, describing the generated volumes, and including the following fields:
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BOUNDARY – The boundary ID as identified using the Keyfield from the input outlines table.
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CUTVOL – the total cut volume within the boundary **
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CUTAREA – The total cut area within the boundary*
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FILLVOL – the total fill volume within the boundary **
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FILLAREA – the total fill area within the boundary*
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COMMAREA – the amount of area that is common to both surfaces within the boundary*
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CREST – The reference top elevation. This will either not be present or contain absent values if no benches have been specified. (Numeric)
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TOE – The reference bottom elevation. This will either not be present or contain absent values if no benches have been specified. (Numeric)
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* The CUTAREA, FILLAREA and COMMAREA fields are only calculated if the Include Areas check box is enabled. This option is unavailable if a third/reference surface is specified.
** The CUTVOL , and FILLVOL fields are only calculated if the Include Volumes check box is enabled.
You can view the generated table using Microsoft Excel (if installed) and/or the Datamine Table Editor.
Evaluation Results:In addition to the summary table, you can also output an evaluation results table. This is only available as an option if theEvaluate the cut and fill volumes against a block modeloption is selected on theEvaluationsub-panel (see above). You can view the generated table using MicrosoftExcel(if installed) and/or the DatamineTable Editor.
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The above tables are created in memory and also saved to disk automatically, as a part of your current project. |
Solids: if selected and specified then an output wireframe object is created that contains the cut and fill solids.
Outlines: if selected and specified then an output string object is created that identifies boundaries of cut and fill.
Remove solids with volume below: automatically strip data (remove complete volumes from output data files if they are below a certain measurement.
Trim solids
with thickness below: this allows you to set a minimum qualifying
thickness distance to see if an aspect of a solid qualifies for inclusion
or removal. This can be a useful method for removing 'noise' from the
resulting cut or fill volumes where a slight misalignment of theoretically
common surfaces exists (for example, the difference in surface topography
between one scan date and the next, or where surface slopes are slightly
different in the area surrounding an excavation or dump.
Take the following example; using a zero thickness setting (meaning a volume
thickness check will not be performed), the resulting cut and fill volumes
contain an outlier fragment and a lot of thin protruding sheets around
both the void and dump volume:
Recalculating the volumes with a minimum
permitted thickness of 10m removes the unwanted data from the resulting
volumes, and the generated outlines are also smoother:
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Volume removal options are data-sensitive and the required setting (if any) will depend on the nature of the two topographies being compared. One potentially useful approach to resolving noisy data is to start with a value that represents 1/10 of the expected bench height, and increase in similar increments until the results appear as expected. Thickness removal is commonly useful when removing data fragments around expected cut and fill volumes (where they intersect with the non-excavated surface), and volume removal can be useful where unexpected/unwanted outlier data fragments exist outside the expected volumes. |
Restore: restore any values entered in a previous cut and fill dialog session (all tabs).
Calculate: initiates the cut and fill command. This option is only enabled when two surfaces have been selected (either by selecting two objects which may or may not have key field and values specified, or the same object twice with different key field / value pairs).
Cancel: dismisses the Cut and Fill Volumes dialog without further action.
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Related Topics |
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DTMCUT
process
wireframe-verify wireframe-decimate |
