| Authors: | Zoltan Siki siki1958 (at) gmail (dot) com |
|---|
Note
This training material does not extend to the use of the program in every detail, further information can be found in other documentation files.
Table of Contents
- Introduction
- Loading sample data set
- View and edit field-books
- View and edit coordinate lists
- Graphic window
- Preliminary coordinates
- Calculations
- Calculation distances and areas
- Coordinate transformation
- Save to DXF file
- Horizontal network adjustment
- Leveling network adjustment
- Digital terrain model
- Regression calculation
The installation kit contains a demodata directory. In this guide the data files from the demodata directory will be used.
Images in this tutorial are generated on an Ubuntu box. Window layouts on different operating systems may look different.
After starting GeoEasy a small windows appears near to the upper left corner of your monitor. It is the main window with a menu and a rotating Earth. If the rotation stopped the software is busy, user have to wait.
Main window
Another window is opened for the calculation results. It has dual function besides the results it has some logging role.
Calculation results window
In the main window select File/Load... from the menu. Navigate to the demodata folder and select test1.geo. A log message appears in the Calculation results window, that data have been loaded.
The loaded field-books can be opened in a window. Select Edit/Observation from the menu of the main window. In a cascading menu the name of the loaded data sets popup, in this case only test1 is visible, select it. Field-book data are displayed in the default mask type.
Note
The mask name is used for dialog boxes containing tabular data. This comes from the display masks which were used on old Leica instruments.
Fieldbook data
Data are arranged in a table, a row contains station or observed point data. Column header can contain more labels (e.g. Signal height and Instrument height). The color of the values in the cells can be different, if more header lines are present, for example signal heights are black, instrument heights are red. Colors can be customized in the File/Colors... menu from the main window.
You can move in the table using the right side scroll bar, up and down arrow keys, mouse wheel (Windows only), TAB/PgUp/PgDn/Ctrl-PgUp/Ctrl-PgDn keys. You can edit the content of the active field, inside the field Home/End/Backspace/Delete/Insert and arrow keys can be used. If the edited value is not valid (e.g. non-numeric value in the distance field) an error message appear and you can not leave the field until the field value is invalid.
The loaded coordinate lists can also be opened in a window. Select Edit/Coordinates from the menu of the main window. In a cascading menu the name of the loaded data sets popup, in this case only test1 is visible, select it. Coordinate data are displayed in the default mask type. Points are ordered in the table by point IDs.
Coordinate data
Data are arranged in a table, a row contains coordinates of a point. Column header can contain more labels (e.g. Easting and Easting prelim.) The color of the values in the cells can be different, eastings are black, preliminary eastings are red. Colors can be customized in the File/Colors... menu from the main window.
Field values can be edited in the same way as in field-books. The default mask for field-books and coordinate lists can be configured in the geo_easy.msk file (geoMaskDefault and cooMaskDefault variables)
Points having horizontal coordinates from all loaded data sets are displayed in graphic window. Select Window/New graphic window from the menu of the main window or press F11 key to open a new graphic window.
Graphic window
Enlarge the size of the graphic window, drag the corner of the window by the mouse and press F3 to zoom to extent. Point symbols, IDs and observations are visible in the graphic window. Red filled circles are stations but not oriented yet.
Let's calculate preliminary coordinates for those points which have no coordinates so far. Select Calculate/Preliminary coordinates from the menu of any window. You'll get a message, that there are no elevations for some points. Several points will be added to the graphic window and the coordinate list. They have red point IDs to mark preliminary coordinates. Preliminary orientations and elevations are also calculated.
Press F5 button to turn off detail points, having a less crowded view in the graphic window (or Commands/Detail points from the menu of the graphic window).
Graphic window detail points turned out
Note
Detail points are selected by the program using the following rules. A detail point has a numeric ID and has only one polar observation and was not station.
The calculation results are listed in the Calculation results window, if you have closed it, open it Window/Log window from the menu of the main window. Calculation results are stored in a log file (geo_easy.log in the user's home directory), so you can review them later. There are calculations for a single point and multiple points. Single point calculations are available from the popup menu, right click on the point in the graphic window or in the row of the point in the coordinate list window or in the field-book window. Multi point calculations are available from the Calculation menu of any window.
Let's calculate the whole circle bearing and distance between points 231 and 13. Click on the point 231 with the right mouse button in the graphic window and select Bearing/Distance from the popup menu. A selection list is displayed with the point IDs having coordinates. You can select one or more point to calculate bearing and distance. Select 13 from the list. The calculation result is visible in the Calculation results window and in the status bar of the graphic window.
Point selection box (window header gives hint how many rows to select)
2023.10.21 23:01 - Bearing/Distance Point num Point num Bearing Distance Slope dis Zenith angle 231 13 293-08-21 4029.889
The slope distance and the zenith angle are calculated only if the elevations of the points are known.
Note
You can use the right mouse button in the field-book or coordinate list windows, too. Right click on the point ID and select Calculate, a cascading menu appears with the possible calculations for the point. If you select the menu item with the point ID an info box will be displayed about the point.
Let's calculate orientation for station 12. Click on the point 12 with the right mouse button in the graphic window. Select Orientation from the popup window. A list with the back-sight directions are displayed, orientation angle in the first column and point ID in the second.
Backsight selection
Select both points (231, 11), use Shift or/and Ctrl keys to select more lines. If you would like to select all rows, click on the All button.
A weighted average will be calculated for the mean orientation angle, the weights are the distances. The calculation results are shown in the Calculation results window.
2023.10.21 23:12 - Orientation - 12 Point num Code Direction Bearing Orient ang Distance e" e"max E(m) 231 232-53-54 291-04-11 58-10-17 2243.319 0 16 0.010 11 334-20-10 32-30-25 58-10-15 1588.873 -1 19 -0.010 Average orientation angle 58-10-16
The e" column contains the difference from the mean, e"(max) is the allowable maximal difference (depending on distance), E(m) is the linear difference at the back-sight point.
Note that the fill color of the point marker of point 12 became green, oriented station. The orientation angles and the mean are stored in the field-book, too. Select the orientation mask from the Commands/Mask... in the field-book window to see them.
You can calculate orientations for all station in a single step, select Calculate/Orientations from the menu of any window. Results are written to the Calculation results window. If the difference from the mean is too large a warning is displayed. The three other unoriented stations are also oriented.
2023.10.22 11:22 - Orientation - 11 Point num Code Direction Bearing Orient ang Distance e" e"max E(m) 12 295-54-35 212-30-25 276-35-50 1588.873 1 19 0.010 14 71-01-11 347-36-58 276-35-47 1637.971 -1 18 -0.010 Average orientation angle 276-35-48 2023.10.22 11:22 - Orientation - 231 Point num Code Direction Bearing Orient ang Distance e" e"max E(m) 15 341-58-03 222-18-10 240-20-07 2615.063 -1 14 -0.023 13 52-48-11 293-08-21 240-20-10 4029.889 1 11 0.023 Average orientation angle 240-20-08 2023.10.22 11:22 - Orientation - 16 Point num Code Direction Bearing Orient ang Distance e" e"max E(m) 14 290-57-39 51-22-38 120-24-59 1425.779 -2 20 -0.016 11 355-25-59 115-51-02 120-25-03 1628.118 2 18 0.016 Average orientation angle 120-25-01
Note
Orientation angles are stored in the field-book, you can see them if you select orientation template (mask). Select the orientation mask from the Commands/Mask... in the field-book window to see them. The calculated orientation angles will overwrite the previous values.
Let's calculate the coordinates of point 5004 using intersection. Four directions were measured from point 11, 12, 231 and 16 to 5004. Stations have to be oriented to be used in intersection. Right mouse button click on point 5004 in the graphic window and select Intersection from the popup menu. A list of possible intersection directions are displayed in the selection window. The field-book name and the point numbers are shown in the list (if more field-books are loaded, stations from any field-book can be used). Select two directions 11 and 12 (best intersection angle).
Intersection point selection
There are two columns in the list window. The first column refers to the data set names, the second column contains point numbers.
Note
This selection dialog is used at several places in the user interface. Check the header of the selection window, how many lines should be selected.
2023.10.22 11:30 - Intersection Point num Code E N Bearing 11 91515.440 2815.220 243-57-51 12 90661.580 1475.280 330-00-58 5004 90246.207 2195.193
Note the color of point number is changed in the graphic window from red to black after calculation done.
Note
You can repeat the intersection calculation selecting different directions. The last calculated coordinates are stored only in the coordinate list. Previous coordinates will be overwritten.
Let's calculate the coordinates of point 5003 in demo data set using resection. There are six possible directions for resection. Let's find the best geometry, 120 degree between directions at 5003. Point 12, 13 and 14 look optimal. Right mouse button click on point 5003 in the graphic window and select Resection from the popup menu. A list of possible resection directions are displayed in the selection window. The field-book name and the point numbers are shown in the list.
Resection from the popup menu
Resection point selection
2023.10.22 11:35 - Resection Point num Code E N Direction Angle 14 91164.160 4415.080 99-10-24 88-42-37 12 90661.580 1475.280 187-53-01 147-41-20 13 84862.540 3865.360 335-34-21 5003 89398.550 2775.210
Note
You can repeat the resection calculation selecting different direction. The last calculated coordinates are stored only in the coordinate list. Previous coordinates will be overwritten.
Let's calculate the coordinates of point 5002 using arcsection. There are three measured distances from 5002 to 11, 12 and 16. Right mouse button click on point 5003 in the graphic window and select Arcsection from the popup menu. A list of possible arcsection directions are displayed in the selection window. The field-book name and the point numbers are shown in the list.
Arcsection from the popup menu
Let's use the distance from point 11 and 12.
Arcsection point selection
2023.10.22 11:41 - Arcsection Point num Code E N Distance 11 91515.440 2815.220 954.730 12 90661.580 1475.280 1117.280 5002 90587.628 2590.110
Note
Using arcsection there are two solution (two intersections of the two circles). If there are more observations for the point to be calculated, GeoEasy can choose the right solution as this case a third distance. Otherwise the user have to select from the two possible solutions.
Note
You can repeat the arcsection calculation selecting different distances. The last calculated coordinates are stored only in the coordinate list. Previous coordinates will be overwritten.
Let's calculate the elevation of point 5003. Right mouse button click on point 5003 in the graphic window and select Elevation from the popup menu. A list of possible elevation calculations are displayed in the selection window. The point name, the elevation and the distance are shown in the list.
Elevation point selection
Let's select both rows. The elevation will be calculated as a weighted average. The weight is inverse proportional of the distance square.
2023.10.22 11:43 - Elevation Point num Code Height Distance 14 118.414 2409.679 11 118.433 2117.268 5003 118.425
Note
You can repeat the elevation calculation selecting different points. The last calculated elevation is stored only in the coordinate list. Previous elevation will be overwritten.
There is a traversing line with three internal points (1_sp, 2_sp, 3_sp) between point 5001 and 5002.
Note
Before you start traversing please make sure the start and end point of the travese line have final coordinates (in black) in the coordinate list and are oriented (green circle). You can use resection for 5001, and intersection for 5002 if necessary.
Let's use the 6th toolbar icon to specify the traversing line. Click on the first point (5001) and the three internal points using the traversing tool and double click on the last point (5002). A black line is draw as you click on points.
Traversing line selection
This is an open traversing with orientation on both known endpoints. A small dialog is shown where you can select the calculation task. Traversing to calculate horizontal coordinates and/or Trigonometric line to calculate elevations.
2023.10.22 11:59 - Traversing Open, two orientation
bearing bw dist
Point angle distance (dE) (dN) dE dN
correction fw dist corrections Easting Northing
0-00-00 -
5001 132-34-50
- 0-00-05 89562.497 3587.526
132-34-45 -
1_sp 134-23-17 498.890 367.354 -337.553 367.374 -337.516
- 0-00-05 - 0.020 0.038 89929.872 3250.011
86-57-57 -
2_sp 228-16-31 330.610 330.147 17.500 330.160 17.525
- 0-00-05 - 0.013 0.025 90260.032 3267.535
135-14-23 -
3_sp 225-08-37 468.460 329.862 -332.634 329.881 -332.599
- 0-00-05 - 0.019 0.035 90589.913 2934.936
180-22-55 -
5002 359-37-10 344.860 -2.299 -344.852 -2.285 -344.826
- 0-00-05 - 0.014 0.026 90587.628 2590.110
0-00-00 1025.131 -997.416
1080-00-25 1642.820 1025.064 -997.540
720-00-00
- 0-00-25 0.066 0.124
0.140
Error limits Angle (sec) Distance (cm)
Main, precise traversing 50 30
Precise traversing 65 38
Main traversing 67 51
Traversing 85 63
Rural main traversing 87 71
Rural traversing 105 89
2023.10.22 11:59 - Trigonometrical line
Height differences
Point Distance Forward Backward Mean Correction Elevation
5001 100.000
498.879 23.947 - 23.947 -0.015
1_sp 123.932
330.625 0.307 - 0.307 -0.007
2_sp 124.233
468.448 12.661 - 12.661 -0.013
3_sp 136.881
344.834 1.926 - 1.926 -0.007
5002 138.800
1642.786 38.842 -0.042 38.800
Error limit: 0.118
Note
Orientations on all stations were calculated previously. Orientation have to be calculated before traversing calculation.
You can start traversing calculation from the Calculation/Traversing menu, too. That case the traversing points are selected from lists.
Some polar detail points were measured from the traversing points. Let's calculate the coordinates for those points. The fastest way to get the coordinates of detail points is to select Calculation/New detail points from the menu. It will calculate orientation angle automatically if necessary.
2023.10.22 12:03 - Orientation - 1_sp
Point num Code Direction Bearing Orient ang Distance e" e"max E(m)
5001 0-00-06 312-34-28 312-34-22 498.879 1 33 0.003
2_sp 134-23-23 86-57-42 312-34-19 330.625 -1 41 -0.003
Average orientation angle 312-34-21
2023.10.22 12:03 - Orientation - 3_sp
Point num Code Direction Bearing Orient ang Distance e" e"max E(m)
2_sp 278-51-33 315-14-06 36-22-33 468.448 -1 35 -0.003
5002 144-00-10 180-22-47 36-22-37 344.834 2 40 0.003
Average orientation angle 36-22-35
2023.10.22 12:03 - Orientation - 2_sp
Point num Code Direction Bearing Orient ang Distance e" e"max E(m)
1_sp 123-44-51 266-57-42 143-12-51 330.625 3 41 0.006
3_sp 352-01-22 135-14-06 143-12-44 468.448 -2 35 -0.006
Average orientation angle 143-12-47
2023.10.22 12:03 - New detail points
Oriented Horizontal
Point num Code E N H Station direction distance
101 89817.629 3124.380 125.301 1_sp 221-46-44 168.468
102 89888.203 3112.688 126.819 1_sp 196-52-47 143.505
103 90043.364 3181.377 126.988 1_sp 121-09-48 132.631
201 90257.670 3134.414 124.353 2_sp 181-00-59 133.142
202 90112.966 3206.386 120.740 2_sp 247-25-22 159.272
301 90543.540 2842.474 139.235 3_sp 206-38-08 103.440
302 90467.017 2904.628 137.424 3_sp 256-08-47 126.578
303 90443.184 2958.512 139.836 3_sp 279-07-41 148.611
Note
You can recalculate all detail points after editing the observation data using Calculate/All detailpoints, you may need to recalculate orientation, too. You can recalculate station by station, right click in the graphic window on a station and select Detail points from the popup menu.
The sum of the horizontal distances between points having coordinates can be calculated in the graphic window using the ruler tool from the toolbar (4th icon). Click on the point marker of the first point and the further points. Finally double click on the last point. A report is sent to Calculation results window.
2023.10.22 12:07 - Distance calculation Point num E N Length 5001 89562.497 3587.526 1_sp 89929.872 3250.011 498.879 2_sp 90260.032 3267.535 330.625 3_sp 90589.913 2934.936 468.448 5002 90587.628 2590.110 344.834 Sum 1642.786
The sum of the distances is shown in the status line of the graphic window, too.
Distance calculation
The next icon, right to the distance calculation is the area calculation. It works similar to the distance calculation. Click on the points of the polygon and double click on the last point (you needn't to click on the first point finally). The calculation result are reported in the Calculation result window.
2023.10.22 12:48 - Area calculation Point num E N Length 101 89817.629 3124.380 102 89888.203 3112.688 71.536 103 90043.364 3181.377 169.685 202 90112.966 3206.386 73.959 201 90257.670 3134.414 161.615 303 90443.184 2958.512 255.650 302 90467.017 2904.628 58.919 301 90543.540 2842.474 98.584 101 89817.629 3124.380 778.728 Area 78674.14098 Perimeter 1668.677 Mean centre 90196.697, 3058.107 Centre of gravity 90191.093, 3054.207
Note
The distance and area calculation is available from the Calculation menu. That case the points are selected from lists.
During a GeoEasy session all points have to be in the same coordinate reference system (CRS) for the calculations. Coordinates can be converted between two CRSs if there are common points in the two system. Two GeoEasy data sets have to be used. The source data set should be opened and select Calculation/Coordinate transformation from the menu. The target data set have to be selected next. Select test1_trafo.geo from the demodata folder. A list of the common points width horizontal coordinates in the two data sets is shown.
Common points for transformation
Select all points and press OK button. In the next dialog box the transformation type can be selected.
Transformation options
Pressing the OK button the transformation parameters are calculated using the least squares method. In the Calculation results window three blocks of information is displayed.
2023.10.22 12:57 - 4 parameters orthogonal transformation test1 -> test_trafo E = 561684.477 + e * 0.999997669 - n * -0.000003434 N = 246411.178 + e * -0.000003434 + n * 0.999997669 Scale = 0.99999767 Rotation = - 0-00-01 Point num e n E N dE dN dist 11 91515.440 2815.220 653199.720 249226.070 -0.007 0.007 0.010 12 90661.580 1475.280 652345.850 247886.150 0.001 -0.007 0.007 13 84862.540 3865.360 646546.830 250276.240 0.002 -0.003 0.004 14 91164.160 4415.080 652848.440 250825.940 -0.001 -0.006 0.006 15 86808.180 347.660 648492.460 246758.540 -0.004 -0.001 0.005 16 90050.240 3525.120 651734.510 249935.970 0.009 0.010 0.014 RMS= 0.008 Point num e n E N 1_sp 89929.872 3250.011 651614.150 249660.872 2_sp 90260.032 3267.535 651944.309 249678.395 3_sp 90589.913 2934.936 652274.189 249345.796 101 89817.629 3124.380 651501.907 249535.242 102 89888.203 3112.688 651572.481 249523.550 103 90043.364 3181.377 651727.642 249592.238 201 90257.670 3134.414 651941.947 249545.275 202 90112.966 3206.386 651797.244 249617.247 231 88568.240 2281.760 650252.518 248692.628 232 88619.860 3159.880 650304.141 249570.746 301 90543.540 2842.474 652227.815 249253.334 302 90467.017 2904.628 652151.293 249315.488 303 90443.184 2958.512 652127.460 249369.372 5001 89562.497 3587.526 651246.778 249998.388 5002 90587.628 2590.110 652271.903 249000.970 5003 89398.550 2775.210 651082.828 249186.074 5004 90246.207 2195.193 651930.481 248606.056
In the first block the formula of the transformation is given. The second block contains the coordinates of common points and the errors. In the third block the transformed coordinates are given, those points can be found here which have coordinates in the source data set but not in the target data set.
Note
If the transformation parameters are known use the Commands/Transformation or Commands/Transformation, parameters from file from the menu of the coordinate list window.
The points with horizontal coordinates from all loaded data sets can be exported into a DXF file. Select Commands/DXF output from the menu of the graphic window. After specifying the output DXF file path, several options can be set for the DXF file in the displayed dialog box.
DXF options
The point symbol (AutoCAD point entities), the point ID and the elevation can be exported to the output. The last block is available if a DTM is loaded.
Let's calculate the coordinates of points 5001, 5002, 5003 and 5004 using all available observations from points. GeoEasy uses GNU Gama (https://www.gnu.org/software/gama/) for the network adjustment.
Before adjustment calculation the a priori standard deviations should be set in the Calculation parameters dialog. 3 arc seconds for directions and 3 mm + 3 ppm for distances.
From the Calculate menu select Horizontal network adjustment. From the first point list select the unknown points (which coordinates are changed during adjustment). This list contains all point having preliminary or final coordinates.
Unknown points
From the second point list select the fixed points (if no fixed points selected then free network will be calculated). This list contains point with final coordinates.
Fixed points
The result of the adjustment is shown in the Calculation results window. During the adjustment statistical tests are calculated to detect blunders but blunders are not eliminated automatically.
Leveling data can be loaded from GSI field-books created by digital leveling instruments (for example Leica DNA03 or NA3000 instruments). Manual input of height differences is also possible.
Let's start with an ASCII file (field-book) which contains start and endpoint, distance, height difference.
B H 232 0.44982
H I 240 -0.07392
I J 416 0.06413
I N 186 -0.10494
K B 90 -0.26894
K N 215 0.00234
J K 806 -0.17131
N H 408 0.17836
N J 634 0.1686
Field-book (leveling.dmp file)
Please close all opened data sets. Let's load this field-book into GeoEasy. Select File/Load from the menu of the main window. Select Fieldbook (*.dmp, *.DMP) type. The leveling.dmp file is in the demodata sub-directory of GeoEasy installation folder. Select the file and click on Open button. A dialog will be displayed where fields of the input file can be set. Remove the unnecessary fields (Horizontal angle, Vertical angle, lope distance, signal height,instrument height) and add horizontal distance and Height diff. leveling. Don't forget to add space to the separators.
Loading leveling.dmp
Open the field-book (Edit/Observations) and change the mask ( Commands/Mask...) to leveling. You can see nine observations.
Observations in leveling mask
These observations were made by digital leveling instrument with a standard deviation of 0.3 mm/km. Change calculation parameters (File/Calculation parameters...), Decimals in results should be changed to 4. Check also Standard deviation for leveling [mm/km], it should be 0.7.
We shall adjust this small leveling network. There are no elevations in the field-book, so first set the elevation of point B to 100.000 (Commands/New point from the menu or F7 button). After it let's calculate preliminary elevations (Calculations/Preliminary coordinates)
Preliminary elevations
Now we can start leveling network adjustment (Calculate/Leveling network adjustment). Select all point as unknown. In the calculation result window a long result list is displayed and the coordinates in the coordinate list are updated.
Adjusted heights
****************
i point approximate correction adjusted std.dev conf.i.
======================= value ====== [m] ====== value ========== [mm] ===
1 B * 100.00000 -0.00002 99.99998 0.1 0.4
2 H * 100.45000 -0.00013 100.44987 0.2 0.4
3 I * 100.37600 0.00001 100.37601 0.1 0.4
4 J * 100.44000 0.00003 100.44003 0.3 0.8
5 N * 100.27100 0.00010 100.27110 0.1 0.4
6 K * 100.26900 0.00000 100.26900 0.1 0.4
Adjusted observations
*********************
i standpoint target observed adjusted std.dev conf.i.
=========================================== value ==== [m|d] ====== [mm|ss] ==
1 B H h dif 0.45000 0.44989 0.2 0.6
2 H I h dif -0.07400 -0.07386 0.2 0.6
3 I J h dif 0.06400 0.06402 0.4 1.0
4 N h dif -0.10500 -0.10492 0.2 0.5
5 K B h dif -0.26900 -0.26902 0.1 0.3
6 N h dif 0.00200 0.00210 0.2 0.5
7 J K h dif -0.17100 -0.17103 0.4 1.1
8 N H h dif 0.17800 0.17877 0.2 0.6
9 J h dif 0.16900 0.16894 0.4 1.0
Adjusted elevations an mean errors in fix_stdev mask
GeoEasy is capable to create TIN based Digital Terrain Models from the points in the loaded data sets or from a DXF file. Triangle open source project is used to generate triangles. There is a small electric field book in the demo data set called terrain.scr. Load the scr file using the File/Load... menu of the main window.
Loading field book
There are 77 points in the coordinate list, let's open a graphic window to see the points and turn off the the yellow observation lines and point name labels using the Commands/Observations F4 and Commands/Point names from the menu of the graphic window.
Note
In the calculation results window you can see a table with collimation and index errors. If the observations were made in two faces, the average of face left and face right will be stored in the field-book.
Note
The colors used in the graphics window can be changed using File/Colors... from the menu of the main window.
Let's start to create a TIN, select DTM/Create... from the menu of the graphic window and press OK button in the Create DTM dialog and select directory and name for the DTM in the Save as dialog.
DTM creation
TIN in the graphic window
The convex hole of the points is filled by triangles which have minimal sum of perimeters. At the side of the model there are narrow triangles. These can be avoided by defining a non-convex boundary for the model. Unload the TIN by DTM/Close from the menu of graphic window. Using the Break line tool from the toolbar draw the boundary of the model.
Non-convex boundary for TIN
Select again the DTM/Create... from the menu and unselect convex boundary checkbox. Triangles are created inside the closed polyline.
Non-convex boundary for TIN
Note
Break lines can be added, those can also be open polylines. If convex boundary is unchecked at least one closed boundary have to be added to the model.
Let's add contours to our model, DTM/Contours from the menu. Input 1 (meter) for contour interval. Finally export contours to an AutoCAD DXF file using Commands/DXF output.
Contours in LibreCAD
Note
TINs are stored in three ASCII files (.pnt for points, .dtm for triangles and .pol for break lines).
Regression calculation can be used to find best fitting geometrical shape to the coordinates of points. Least square adjustment is used to find the parameters of the best fitting geometry. The reg.geo data set in the demodata folder will be used in this chapter. Load the data set to try regression algorithms and close other opened data sets.
Crane track points
Observations were made along a crane track. Points from 1 to 7 are on the right rail and points from 8 to 14 on the left rail. Let's first fit a 2D line on the right side rail, Calculate/Regression calculation/2D Line from the menu.
2023.10.22 14:07 - 2D Line
N = +0.71863307 * E -100.619
Angle from east: 35-42-08
Correlation coefficient: 1.000
Point num E N dE dN dist
1 223.563 60.040 -0.001 0.001 0.001
2 231.684 65.879 0.001 -0.001 0.001
3 239.801 71.714 0.002 -0.002 0.003
4 247.926 77.543 -0.003 0.004 0.005
5 256.046 83.388 0.002 -0.002 0.003
6 264.161 89.211 -0.002 0.003 0.004
7 272.285 95.058 0.002 -0.002 0.003
RMS=0.003
The results are printed in the Calculation results window. Beside the equation of the line the direction and correlation are also calculated. From the table of the point-line distances (dist) can be read.
This case we had better to fit two parallel lines using Calculate/Regression calculation/Parallel 2D lines. From the first point list select the points on right side rail (1-7) and press OK. From the second point list select points on left side rails (8-14).
2023.10.22 14:11 - Parallel 2D lines
N = +0.71870599 * E -100.637
N = +0.71870599 * E -90.785
Angle from east: 35-42-18
Horizontal distance: 8.000
Correlation coefficient: 1.000
Point num E N dE dN dist
1 223.563 60.040 0.000 -0.000 0.001
2 231.684 65.879 0.001 -0.002 0.002
3 239.801 71.714 0.002 -0.003 0.003
4 247.926 77.543 -0.003 0.004 0.005
5 256.046 83.388 0.001 -0.002 0.002
6 264.161 89.211 -0.003 0.004 0.005
7 272.285 95.058 0.001 -0.001 0.001
8 218.896 66.533 -0.002 0.003 0.003
9 227.017 72.376 0.001 -0.002 0.002
10 235.137 78.206 -0.002 0.002 0.003
11 243.254 84.045 0.001 -0.001 0.001
12 251.374 89.883 0.002 -0.002 0.003
13 259.496 95.715 -0.001 0.001 0.001
14 267.611 101.550 0.001 -0.001 0.001
RMS=0.004
On a diaphragm wall points were scanned by a robotic total station, points from Scan0676 to Scan0915. Let's check if the wall is vertical using Calculate/Regression calculation/Vertical plane. In the point list select all Scan points and press OK.
2023.10.22 14:14 - Vertical plane
N = -0.00119324 * E +0.054
Angle from east: - 0-04-06
Correlation coefficient: -0.390
Point num E N dE dN dist
Scan0676 68.799 -0.004 -0.000 -0.024 0.024
Scan0677 67.798 -0.004 -0.000 -0.022 0.022
Scan0678 66.789 0.002 -0.000 -0.028 0.028
Scan0679 65.790 0.001 -0.000 -0.026 0.026
Scan0680 64.789 0.001 -0.000 -0.024 0.024
Scan0681 63.788 0.003 -0.000 -0.025 0.025
Scan0682 62.786 0.003 -0.000 -0.024 0.024
...
RMS=0.024
We got two points for the planned position of the diaphragm wall, these are points S2 and S3. Let's check the distances from the planned position. Select Calculate/Regression calculation/Distance from line from the menu (vertical plane is the same as 2D line in this situation). First select the two points from the plan S2 and S3 from the point list. From the second point list select Scan points. In the Calculation results list we get the distances of the scanned points from the planned positions.
2023.10.22 14:25 - Distance from the S2 - S3 line
Point num E N Distance dE dN
Scan0676 68.799 -0.004 -0.004 0.000 0.004
Scan0677 67.798 -0.004 -0.004 0.000 0.004
Scan0678 66.789 0.002 0.002 0.000 -0.002
Scan0679 65.790 0.001 0.001 0.000 -0.001
Scan0680 64.789 0.001 0.001 0.000 -0.001
Scan0681 63.788 0.003 0.003 0.000 -0.003
Scan0682 62.786 0.003 0.003 0.000 -0.003
Scan0683 61.785 0.003 0.003 0.000 -0.003
Scan0684 60.784 0.002 0.002 0.000 -0.002
Scan0685 59.784 0.003 0.003 0.000 -0.003
...
Max distance: 0.083
There are points on five horizontal sections of a chimney. Let's fit a regression circle on lowest section, point ids like '1nn'. Select Calculate/Regression calculation/Circle from the menu of any window. A list of point ids is displayed in a new window. Select all points from 111 to 133 and press OK button. You will be asked for the radius of the circle. Let the unknown value in the input box to calculate radius from the data. You can give a radius if it is known and you don't want to get an estimated value from the circle regression.
Points for circle regression
Optionally you can enter the radius of the the circle if it is known. Let radius field empty to calculate it from the input data. The result of the calculation is displayed in the Calculation results window. E0 and N0 are the coordinates of the center of the circle, R is the radius. The tabular data show the coordinates of the used points and the differences from the best fitting circle (in east, north and radial direction).
2023.10.22 14:40 - Circle
E0 = 635.693 N0 = 271.517 R = 2.442
Point num E N dE dN dR
111 633.661 270.152 0.005 0.003 -0.005
112 635.355 269.096 0.000 0.002 -0.002
113 637.586 269.966 -0.004 0.003 -0.005
121 633.975 269.779 0.001 0.001 -0.001
122 634.477 269.404 -0.002 -0.004 0.005
123 634.520 269.378 -0.001 -0.003 0.003
124 634.520 269.378 -0.001 -0.003 0.003
131 637.898 270.468 0.000 -0.000 0.000
132 638.132 271.428 0.001 -0.000 0.001
133 638.129 271.655 0.002 0.000 0.002
RMS=0.003