Combine models Combine modelsCombining two terrain models to give a difference in surface height. The resulting model is a triangle net, in which the Z coordinate is the height difference of the two original nets. Triangles from the both nets are included in the combined model and also all the break lines. The intersection line between the two models is added into the resulting model to get absolute accuracy for volume calculation.
The new file, which is technically normal terrain model, can be used for volume calculation and contour line calculation. In the created triangle net, the areas above and below the zero height will be colored differently.
Volume calculation is based on surface codes. Be sure to have the correct codes, and if need be, change the codes in edit model.
The different areas (cubic and square meters) are shown using different colors after calculation, if both settings 'Volumes' and 'Result file' are selected. Use Point view/Areas to set raster painting on or off. The code used for area painting is calculated by adding 9800 to the surface code. Earth dig areas use code 9801, rock quarry uses code 9802, fill areas use code 9811, etc.
The dialog shows the area and volume of the some surfaces. Rest of the volumes and surfaces will be shown in the result file. Volume calculation results are stored also to file as attributes. Volume attributes are named VOL_x, where the x is surface id. For example, rock volumes are stored to attribute VOL_2. These attributes can be used to show volumes on screen using title files.
Determines how the combined model is created. First two options calculate difference model, which means that combined model’s height values are difference between the height values of original models. First option calulates also volumes. Minimum takes the lower height of two models, Maximum upper height and Average center between them.
Minimum or maximum surface with slopes copy the second surface edge outwards and add this line to the first surface before combining models. This creates steep slopes at the edges of the second surface. Amount of side offset is five centimeters by default, but it can be changed with the special setting SlopeOffset.
Method Check upper surface raises surface 1 points at least to surface 2 level. Method Check lower surface lowers surface 2 points at least to surface 1 level. Both methods first go through the target surface and change point heights if needed. After that, other surface points are checked and if necessary, new points are added to the target surface. Actual combination is not made, because it could create too big results with big surface models. Note that you can use dZ-values to change model heights before calculation.
The program has chosen default values for the upper and lower surfaces, and they will appear in the dialog. You may choose from the list any of the models in use, or the standard plane.
Surfaces can be given in any order. Calculation result is always based on model surface codes. Rules are same as in cross section volume calculation. If there are any problems in combining models, surfaces in lists can be swapped. This changes interal combining order. Same effect can be achieved by pressing Shift-Do it. If the other surface is fixed plane, it is handled as a construct surface (11). However, if the other model is already construct surface, fixed plane behaves as earth surface (1).
Combining with the Alt-key forces surfaces to rock (2) and construct (11).
One of the models can be replaced with the standard plane. There is no model as such, but a surface is formed from the given plane (Z-height).
Displays model's real internal surface id. It can be changed with model edit function. For fixed planes construction surface id 11 is used unless the other model already uses it, in which case earth surface id 1 is used.
The given model (upper or lower surface, or standard plane) can be raised or lowered with a given value. The raising or lowering value is always taken from the original height. So, its effect is not accumulative.
Surface denotes what surface code the model is saved with. This surface code also decides the names of the created files. If the surface code is e.g. 0 (zero), the difference model will appear as *.TM0.
Value m²-limit is thickness limit for rock volumes (2). If the thickness of rock is lower than this value, it is listed separately as area. Slope is minimum slope for bottom of the rock volume. If the construct surface slope is steeper than given value, rock is handled as volume regardless its thickness.
The border file name. The border file is normal vector file in the element list. The lines in the file will be inserted to the result file and only triangles within the border will be calculated. If there are several border lines, volumes are calculated separately for each area. Border lines must be closed and thay must have line number, which is used as an area id in the result file. If the border lines overlap, volumes are added only to the first area.
Calculates volumes outside of given border file lines.
Stores calculated volumes to border line attributes.
Includes slope areas of all surfaces into result file. Areas are calculated only from upper surface of the surface volume areas.
Determines the format of the result file. If the checkbox is selected, array format is used. Otherwise, list format is used. Array format is more suitable for transferring results to spreadsheet program. See examples at the bottom of page.
Number fo decimals in volume calculation results. Negative values round to nearest power of ten: -1 to nearest 10 and -2 to nearest 100.
Every area separately, if border file has multiple lines. Only closed lines can be used as border lines.
Saves combined model areas to a new separate vector element. With the Shift-key selects the intersection line/lines of the two models (height difference=0), gets height to every point of this line from one of the models and saves this line into a new vector file element.
The results of the volume calculation are displayed in the result file [user]/volume_combine.txt. You can view the results in text editor after the calculation. Settings affecting format of the result can be changed and the result file displayed again without recalculation of volumes.
With the Shift-key the result file is written using tabulators as column separators. This makes it easy to copy result value columns to Excel. Decimal separator is comma by default, but it can be changed with special setting ResultDecimal. With the Alt-key the result file is written with template file.
The surface names are set in the code file. Notice that you can specify two names separated by semicolon where the latter one is used in result file for volume calculation.
There are also two other methods for volume calculation: grid volumes and cross sections.
Example of list type output:
Volume Calculation : Terrain model
Z-limit: 1.00 (Slope 7.00)
Border file: C:\Users\Mikko\Data\Model\Volume\Kasa\raja.xyz
Files:
C:\Users\Mikko\Data\Model\Volume\Kasa\pohja.mm1 (dz = 0.00)
C:\Users\Mikko\Data\Model\Volume\Kasa\kasa.mm11 (dz = 0.00)
Total
Surface Area Volume Code
Täyttö 9727.90 74033.02 11
Area: Area2
Surface Area Volume Code
Täyttö 4020.35 47351.66 11
Area: Area1
Surface Area Volume Code
Täyttö 5707.55 26681.36 11
Example of array type output:
Volume Calculation : Terrain model
Z-limit: 1.00 (Slope 7.00)
Border file: C:\Users\Mikko\Data\Model\Volume\Kasa\raja.xyz
Files:
C:\Users\Mikko\Data\Model\Volume\Kasa\pohja.mm1 (dz = 0.00)
C:\Users\Mikko\Data\Model\Volume\Kasa\kasa.mm11 (dz = 0.00)
Surface Täyttö (11)
Area Volume
Area: Area2 4020.35 47351.66
Area: Area1 5707.55 26681.36
Total 9727.90 74033.02
There are some special settings related to this function.
If not zero, calculates rock drill areas for locations where construction steepness is greater than the given limit.
Decimal separator used with tabulated result file. Either comma (0) or point (1).
Model edge side offset when using combination method minimum or maximum surface with slopes.
See also: Using special settings