DTM FUNCTION IN SURPAC (MINING SOFTWARE)

2. Digital Terrain Model
Presentation on

3. Content
 Introduction
 Creating a DTM
 Create a DTM contours
 DTM volume calculation
 Editing a DTM
 summary

4. Introduction
 A Digital Terrain Model (DTM)
represents the topography of a project
 Digital Terrain Models can be
generated from survey data,
photogrammetry data geometry data
 The DTM can be drawn in a 2D or 3D
file
 We can rotate the DTM to see the
existing surface of the project area

5. PROCESSIN
G
ANALYSIS
VISUALIZINGAPPLICATION
DTM
REAL
WORLD
DATA
ACQUISITIO
N

7. Application
 Planning
 Engineering
 Height analysis
 Visualisation
 Soil erosion modelling
 Flow direction and
accumulation
 Wind flow and pollution
dispersion

8. KeyFeatures
.
 DTM data can also be used
in a GIS to create thematic
maps, grids and contours.
 Available in 10m grid
intervals
Key Features

9. Technical
Information
 95% of the data is within +/-1.0m
accuracy
 DTMs can be used to generate 3D
TINs

10. Functionof
DTM

11. SurfaceModellingConcepts

12. .

13. Creating a DTM
It is important to understand how a string file relates to a dtm. Once a dtm has
been created, any modifications to the string file will make the DTM invalid.
Hence, if modifications are made to string data, you will need to recreate the
DTM

14. CreatingDTMcanbe
doneintwoways:
1-Graphicalcreation
2- FilebasedDTM
creation
 1. Graphical Creation
 Open the file topo1.str in SURPAC
 From the Surfaces menu, select Create DTM from
layer.


15. Graphical
Creation
 Click Apply on the form to create a DTM surface.
 Since the data you are working on is a copy of the
original data, the file must always be saved after the
DTM creation.
 From the File menu, select Save, then String/DTM, to
save the DTM file
 Enter the data as shown below, then click Apply

16. Graphical
Creation
 Because the string file and dtm already exist, you will
be asked if you wish to replace them. Click Yes.
 Your results should like the diagram below:

17. FilebasedDTM
creation
 2. File based DTM creation
 We will now create a DTM from the string file pit1.str
using the file based DTM creation option. We will use
this function to demonstrate the impact of using
strings as breaklines.
 From the Surfaces menu, select DTM File functions,
then Create DTM from string file.
 Fill in the form as shown below, then click Apply.

18. FilebasedDTM
creation
 Note: The Strings to act as break lines checkbox is
NOT ticked
 Note: The ability to clip to a boundary string at the
same time as creating the DTM is new functionality
introduced in Surpac Vision V5.2D. In earlier versions,
or if you wish to clip a DTM from a string file after the
DTM has been created, use the function Clip DTM
from boundary string under the DTM file functions
menu.
 Open the file pit1.dtm in Graphics. You should see
something similar to that shown below:

19. FilebasedDTM
creation
 Note that there are several triangles in the dtm that do
not reflect the results we desire. We will now repeat
the procedure, but using strings to act as breaklines.
 From the Surfaces menu, select DTM File functions,
then Create DTM from string file. This time ensure
that the checkbox for Strings to act as break lines is
ticked.
 Fill in the form as shown below and click Apply.

20. FilebasedDTM
creation
 • The message window informs you of the processing
as the DTM is created. When processing is finished,
you will see a log file, which is a small report
containing information about your DTM. Close the file
to continue.
 • The DTM file is saved automatically as pit1.dtm.
 Open the file pit1.dtm in Graphics. You should see
something similar to that shown below:

21. Creating a DTM contours
.

22. Example:Plot contour from dtm using surpac
Take a string file as shown in fig below

23. Go to surface and create a dtm from a layer

24. Created DTMfile
appears justlike a
figurebelow
Created DTM file appears just like a
figure below

25. Gotosurfaceandincontouringdialogboxclickondtmfileand
Gotosurfaceandincontouringdialogboxclickondtmfileand
selectthecontourfilewhichisalreadycreatedandclickokselect
thecontourfilewhichisalreadycreated andclickok.

27. Thecreated
contour filewill
appear asshown
figurebelow
The created contour file will appear as
shown figure below

28. .
To find out the value of a
particular string i.e. the
value of a contour line
follow the steps below
In the command tool
which is present at
the bottom, insert DRAWZ
And click ok . A dialog box
appear in that click on
centroid and apply

29. The actual contour will appear as shown in the
figure below

30. .
 Thus by using a DTM various applications such
as digitalising of a contour, volume calculation,
open pit model ,height analysis etc. can be
calculated using DTM in surpac

31. DELETE TRIANGLES
FROM A DTM IN SURPAC
.

32. .
 As We Know That DTM Is an addition of Number of
Solid Triangles . Now we are going to see how to
remove/delete those triangles from a DTM in
SURPAC…
STEP 1 :
OPEN A DTM IN SURPAC

34. .
 Now Click On the ‘SOLIDS’ on top of the screen .There
you get an ‘Edit Triangle’ option.
 Now Click on it where you will get a different options
to delete the different types of triangles present In different locations of
that DTM.

35. solids
Edit Triangle
Delete single
Triangles
Delete
Triangles
attached to a
segment
Delete Triangles
inside a segment
Delete
Triangles
connected To
a point

37. .
 Thus DTM can be used in various field of
applications

38. .

39. Stepsusingin
volume
calcilation
1. Create a boundary string :-
A boundary string file can be used for: •
delineating cut and fill material for calculating volumes • finding the
intersection of a fault plane with a surface • finding where a pit design breaks
the natural surface.
There are two ways to create the boundary string in Surpac Vision
a. File-based method
there is no need to display the DTMs and
the boundary string is automatically saved to the nominated file
b. Graphics-based method
In the graphics-based method, the
DTMs must be displayed in graphics and the boundary string is not automatically
saved but is simply displayed in its own graphics layer. You must save your
boundary string to a file after it is generated.

40. a.File-based
method
 .
(Note that the pit extends past the natural topography. To determine the
volume of the pit, we need to define the boundary where the topography cuts the pit
design, otherwise our volume estimates will be incorrect. We do this by creating a
boundary string of the intersection between both DTMs.)
From the Surfaces menu, select DTM File functions, then Line of
intersection between two DTMs.
Once we have the boundary string we can use it to constrain our
volumes calculation.

41. b.Graphics-
basedmethod
 From the Surfaces menu, select Clip or intersect
DTMs, then Line of intersection between two DTMs.
Complete the form as shown below, then click Apply.
This outputs the same result as the file based functions, but
the fields can be selected graphically. In the graphics-based
method, you need to save the string in the intersection layer
to a string file if you wish to use it for further processing.
After applying this form the result is
displayed in the graphics and should look something like
the diagram below:

42. 2.CutandFill
BetweenDTMs
 We will now use the function Cut and fill between
DTMs function from the Volumes menu
From the Volumes menu, select Cut and fill
between DTMs. Fill in the form as shown below then
click Apply.

58.  .

59. Summary
 String file (*.str) contains spatial data
 A DTM is a digital terrain model which is an indexed
list of triangles which contain no spatial data
 A DTM file is invalid without its associated string file
 Triangles are referenced in 3-D space by points in
strings and the triangles are formed by connecting
groups of three data points together by taking their
spatial location in the X - Y plane into account.
 Vertices of triangle coincident with a string point.

60. .
.