integration of traverse computations and cad by …

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UDC 69.05

A. Serwa1, Hossam H. El-Semary2

INTEGRATION OF TRAVERSE COMPUTATIONS AND CAD BY DEVELOPING

OF TRAVCAD SW PACKAGE

Helwan University

Egypt, Cairo, e-mail: [email protected] 1Dr., Asst. Prof. of Surveying, Faculty of Engineering in El-Mataria

Benha University

Egypt, Cairo, e-mail: [email protected] 2Dr.,.Asst. Prof. of Surveying, Faculty of Engineering in Shoubra

Statement of the problem. Traversing is one of plane surveying operations which is a traditional

methodology that can be used to map the earth. The rapid development in instrumentation and

computer dependency led to the need to develop plane surveying SW. Civil Engineering students

suffered from the lack of illustration when the study of traversing is coming out. One can not fly to

view the traverse but SW can show a planemetric view. SW gives the better solutions with feasible

budget instead of manual and practical one. The integration between observations, computations

and illustration made development of educational SW is an optimized solution.

Conclusions. This research work is providing free software’s as well as traversing data at abso-

lutely free of cost. Initiatives of the educationist, researchers and software developers in the field

of plane surveying may be benefited from this research work. An effort has been made to review

the main components of the developed SW.

Key words: Educational, Civil Engineering, Plane Surveying, Web, Traverse, CAD interface, SW Development.

Introduction

As plane surveying is an important branch of surveying, the need of development plane sur-

veying SW comprised. In present scenario, where the educational techniques are becoming

more interactive and attractive with the aid of geomatics tools, the role of developed SW is

noteworthy. Civil engineering students need to apply the integration between surveying, SW

development, CAD and web. These new integrating tools and techniques have been comple-

menting or replacing established surveying techniques and geoinformation production process

[Beek et al, 1996].

© Serwa A., H. El-Semary Hossam, 2016

Scientific Herald of the Voronezh State University of Architecture and Civil Engineering. Construction and Architecture

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Computer programming is the iterative process of writing or editing source code. Editing source

code involves testing, analyzing, and refining, and sometimes coordinating with other program-

mers on a jointly developed program. (Adejare, 2003) also wrote a similar algorithm using Mi-

crosoft Excel Spread Sheet [Odumosu, J. O, et. al, 2014]. Ruchel, 2010, developed software

package caries out geodetic computation. The main objective of this research work is to develop

a comparative SW that can be expressed as self-developed SW. Hashimi, 2004, used Microsoft

Excel Solver to apply traverse Adjustment. The integration between traverse computations and

CAD is an important part of the research. The developed system is called TravCAD. One must

develop a self-developed SW in order to fulfill some research requirements [Serwa, 2003]. Some

of existing SW has enigmatic tasks that prevent researchers from make some improvements

[Serwa, 2009]. This research aims to develop object oriented software with friendly GUI (Graph-

ical User Interface) for traverse computations concerned with course of plane surveying.

1. Types of traverses

There are two kinds of traverses: closed and open (depending on the information constraints).

Two categories of closed traverses exist: polygon and link. In the polygon traverse, as shown

in Figure.1 (a), the lines return to the starting point, thus forming a closed Figure that is both

geometrically and mathematically closed. Link traverses finish upon another station that

should have a positional accuracy equal to or greater than that of the starting point. The link

type (geometrically open, mathematically closed), as illustrated in Figure 1(b), must have a

closing reference direction, for example, line E-Az Mk. Closed traverses provide checks on the

observed angles and distances, which is an extremely important consideration. They are used

extensively in control, construction, property, and topographic surveys [Ghilani & Wolf, 2012].

Figure 2 shows an example of open traverse.

Fig. 1. Examples of closed traverses [after Ghilani & Wolf, 2012]

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Fig. 2. Example of an open traverse [after Ghilani & Wolf, 2012]

One can extract three types of computational traverses as follow:

1 –– Closed polygon traverse.

2 –– Closed linked traverse.

3 –– Open traverse.

The first two types of computational traverse can be checked mathematically and can be ad-

justed due to the existence of conditions. The third type can not be checked or adjusted but

only can be plotted.

2. Traverse Computations

In closed polygon traverse the minimum known parameters are:

1 –– Correct coordinates of a point.

2 –– Correct direction of a side (it is better if the known point lays on it).

3 –– Observed angles between sides.

4 –– Observed side lengths.

One can abstract general computations steps as follow:

Step 1: Computation of angles misclosure.

Step 2: Balancing angles.

Step 3: Computation of preliminary directions.

Step 4: Computation of departures and latitudes.

Step 5: Computation of linear misclosure.

Step 6: Traverse adjustment.

Step 7: Computation of final coordinates.

The correct sum of internal angles can be computed as follow:

∑= (n – 2) 180o. (1)

One can use the sum of external angles which can be computed using:

∑= (n + 2) 180o. (2)


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In order to compute the angles misclosure one need to compute the sum of observed angles

∑\. Then the angles misclosure can be computed as follows:

Angles misclosure = ∑ – ∑\. (3)

The permissible angles misclosure C in seconds can be computed as follows:

C = K √n. (4)

Where: n is the number of observed angles and K is a constant depend on the level of traverse

accuracy. According to Federal Geodetic Control Subcommittee (FGCS) K takes the follow-

ing values:

First-order class I = 1.7"

Second-order class I=3"

Second-order class II=4.5"

Third-order class I=10"

Third order class II=12"

There are two methods of balancing angles [Ghilani & Wolf, 2012]:

1 –– Applying an average correction to each angle where observing conditions were approx-

imately the same at all stations. The correction for each angle is found by dividing the total

angular misclosure by the number of angles.

2 –– Making larger corrections to angles where poor observing conditions were found.

The first method is widely used because of the lack of knowledge related to observation con-

ditions.

The preliminary whole circle bearings (WCB) can be computed as follows:

WCBfore= WCBback ± Corrected Angle ± 180o. (5)

The angle in between is positive if it was observed clockwise and it will be negative if it was

observed anti- clockwise.

The departure and latitude of sides of the traverse can be computed as follows:

Departure = Length* Sin (WCB) (6)

Latitude = Length* Cos (WCB) (7)

Departure misclosure is the algebraic sum of all traverse departures and the same for latitude

misclosure. So the linear misclosure can be computed as follows:

departure misclosure latitude misclosure (8)

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The relative precision can be computed as:

relative precision =

(9)

Traverse adjustment can be carried out by computing the corrections of both departure and

latitude of any side AB using the following equation:

correction in departure for AB –

length of AB,

correction in latitude for AB –

length of AB. (10)

Then the adjusted departure and latitude can be obtained by adding the corrections to the

computed departures and latitudes.

The final coordinates can be computed as follow:

XB = XA + Departure of AB.

YB = YA + Latitude of AB. (11)

3. Closed Linked Traverse

In closed linked traverse the minimum known parameters are:

1 –– Correct coordinates of both starting and ending points of the traverse.

2 –– Correct directions of both starting and ending sides (the starting and ending known

points lays on them).

3 –– Observed angles between sides.

4 –– Observed side lengths.

One can abstract general computations steps as follow:

Step 1: Computation of directional misclosure.

Step 2: Balancing directions accumulatively.

Step 3: Link stating and ending points to form a virtual polygon.

Step 4: Computation of departures and latitudes.

Step 5: Computation of linear misclosure.

Step 6: Traverse adjustment excluding the linking side.

Step 7: Computation of final coordinates.

The directional misclosure can be computed by using equation (5) starting with the first

known WBC and the observed angles between traverse sides until reaching the ending known

side. One can compute directional misclosure by comparing the computed WCB and the

known WCB of the ending side.


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The balancing values can be obtained accumulatively using the equation:

Δi = (i – 1) (WCBn-known – WCBn-computed) (i = 1, 2...n). (12)

Where:

Δi is the directional correction of side order i, n is the order of the ending traverse side.

The rest steps of closed linked traverse are similar to the steps of closed polygon traverse ex-

cept that the linking side does not take any correction in departure and latitude because they

are correct values.

4. Open Traverse

Open traverse can only be plotted using starting known point and the observed lengths and the

observed angles. There is no adjustment can be carried out for this type of traverses and so

one can avoid forming this type in surveying projects.

5. TravCAD Development

In order to achieve the research objective SW development life cycle using the water fall

software model was adopted as shown in Figure 3.

Fig. 3. SW development life cycle using water fall model

Initiation & Feasibility: one can review current systems to see how to improve if possible.

One did a feasibility study on the current systems to see if making a new system is feasible or

not. By the end of the study one should have a project plan for the future stages of the cycle.

Investigation: one have to do a detailed investigation of the users needs, so one knows how

the system will work. From this investigation one also is able to identify the inputs, processes,

outputs and data flows by using all the information got from the current systems.

Requirement, analysis and specification: one must gather up all the information and plan out

what the TravCAD system will be able to do.

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Design: This stage helps to identify how the TravCAD system will look and run in details

such as the interface design and coding.

Build: the developer use the plan that the design stage made and basically convert the infor-

mation they got into computer code. Computer programs were written for every part of the

system, normally done as series of modules in the project.

Testing: In this stage one used the test plans that should have been created in the design stage

to test the system, so a check were carried out. A real life data were used to insure the reliabil-

ity of the TravCAD.

Implementation: one needs to make sure that it has very few or no problems for system users.

When the system is being installed the users will then be trained in how to use the new system.

Maintenance: This is the final step in the cycle. Users of the developed system can report

bugs they are dealt with. Some improvements can be applied on the system or the cycle can

be returned to the first stage according to the conclusions and reports.

TravCAD SW was developed using VB6 programming language. It consists in this version of

the following forms:

1 –– Starting form: Contains author affiliation and institution as shown in Figure 4.

Fig. 4. Starting Form

2 –– Identification form: identify SW name and purpose as shown in Figure 5.

Fig. 5. Identification Form


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3 –– Main form: Contains functions commands to the left, CAD module (Figure 6a) and cal-

culations table (Figure 6b).

Fig. 6: a) Main form with CAD module, b) Main form with calculation table

Some advanced tasks can be found in the main form such as:

–– Read traverse file.

–– Show polygon (1:1 scale)

–– Show calculation table.

–– Solve (apply all steps of traverse computations as mentioned in section (3-2).

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–– Save as BMP (save the traverse image as displayed).

–– Save as HTML (save the traverse image and calculation table in HTML format in order to

publish it on the web.

–– Save DXF (export the traverse to the AutoCAD environment).

–– Save as TXT (export the traverse final coordinates in ASCii format).

4 –– Compass form: it is a tutorial form to make the user familiar with WCB and directions

as shown in Figure 7.

Fig. 7. Compass form

5 –– Components form: it is a calculator for departure and latitude from known length and

WBC according to equation (6) and (7). The polar components (length and WBC) can also be

computed as shown in Figure 8.

Fig. 8. Component form


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6 –– Coordinates form: it is a calculator for coordinates of points from known coordinates of

previous point and the components of the containing line. Also it can calculate components of

a line from coordinates of two belonging points as shown in Figure 9.

Fig. 9. Coordinates form

7 –– Angle form: it is a tutorial form that enables the engineer to understand and apply the

relation between two lines and the angle in between according to equation (5) as shown in

Figure 10.

Fig. 10. Angle form 8 –– CAD module: it contains additional tasks such as:

–– CAD interaction tasks such as zoom in, zoom out, zoom window, zoom previous and pan.

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–– Computing area and perimeter of the traverse.

–– Display grid scale 1:1

–– Display Compass on any traverse point.

Most of these tasks shown in Figure 11.

Fig. 11. CAD Module

The software shall link with web using HTML output. Another privilege is CAD interface and

output including: advanced zoom (in, out, window, extent and undo) in addition to DXF oper-

ations such as point extraction and output. With its name, it has a great privilege of CAD fa-

miliarity that eases of surveying drawings treatment. Zoom in, zoom out, zoom window and

zoom previous for example makes the developed SW familiar to civil engineers. The compa-

tibility between the developed SW and AutoCAD is a strong point to allow the user to store

and retrieve data between the two SW. File processing between TravCAD and AutoCAD can

be expressed in DXF file conversion. TravCAD can convert point ASCii format to DXF for-

mat in order to display the adjusted traverse in AutoCAD to continue surveying work. The

last notice is that the first author has the only commercial rights concerned with TravCAD.

4 –– Application: In order to proof TravCAD reliability an example of textbook of "Elemen-

tary Surveying –– An Introduction to Geomatics 13th ed –– E. Ghilani, P. Wolf" were

adopted as follow: The given example can be shown in Figure 12.


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Fig. 12. Example of closed polygon traverse [after Ghilani & Wolf, 2012]

The TravCAD file format including the given data and the method of adjustment can be indi-

cated in Figure 13. TravCAD file formats differ according to the first line of the file (the type

of the traverse). The format of closed polygon file is as following:

–– Type of the traverse.

–– Number of sides.

–– WBC of starting side.

–– Side lengths.

–– Internal angles.

–– Coordinate of starting point.

–– Adjustment method.

Fig. 13. TravCAD format file for closed polygon traverse

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6. Results and Analysis

The results of TravCAD can be shown in Figure 6 a), 6 b) and table 1, while the textbook so-

lution is shown in table 2. The solution of TravCAD is more precise because of the computed

departures, latitudes and coordinates is in the format of (*.###) while Ghilani & Wolf, 2012

using the format of (*.##). The coordinates of the sample points were computed manually to

check for the existence of significant difference or discrepancy between TravCAD.

Table 1 Example solution given by Ghilani & Wolf, 2012

Table 2 Example solution given by Ghilani & Wolf, 2012

7. Statistical Test

SPSS SW was used in testing whether the two sets of computed coordinates (TravCAD and

Ghilani & Wolf, 2012) were from population with the same mean. The Student-T distribution


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test was carried out to determine the confidence interval of computed X and Y coordinate.

The test was carried out to test if there is any significant difference. Both the null hypothesis

and the alternative hypothesis were assumed. The Level of significance was chosen to be

95%. Since the population is < 30, the student-t distribution shall be used. The student-t dis-

tribution is expressed as:

t =

/ / (13)

Where:

μ1, X1: is average mean error and sample mean of the solution given by Ghilani & Wolf,

2012.

μ2, X2: is average mean error and sample mean of the solution given by TravCAD. The both

solutions can be seen identical; therefore, we accept the null hypothesis that there is no sig-

nificant difference between the TravCAD and Ghilani & Wolf, 2012 in computing coordi-

nates.

Conclusion

The research objective was achieved by developing and testing the developed system. Trav-

CAD used equations that are commonly in the field of surveying computations. It can be ob-

vious that all methods can be applied in TravCAD. TravCAD is reliable in traverse computa-

tions process depending on results comparison with solved example in famous textbooks. One

can use TravCAD to have a facility and time reduction in traverse computations, in addition

to avoid human errors. The integration of traverse computation and CAD system can be pre-

sented in TravCAD.

One must recommend making further steps in the field of development of self-made survey-

ing SW. There are some important surveying operation had to be covered using a self-made

SW in order to satisfy the needs of both engineers and students of civil engineering.

References

1. Adejare, Q. A. Comparative Package for Surveying Computations using Hot Sheet, Unpublished B.Eng. The-

sis submitted to the Department of Surveying and Geoinformatics / Q. A. Adejare. –– Nigeria : University of

Lagos, 2003.

2. Beek, K. J. Geoinformation: A world in motion. Paper presented on the occasion of the 40th Anniversary of

Wuhan Technical University of Surveying and Mapping (WTUSM), 16––19 October / K. J. Beek, C. M. Paresi,

1996.

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3. Ghilani, C. D. Elementary Surveying: An Introduction to Geomatics. Pearson Education Inc. 13th Edition /

C. D. Ghilani, P. R. Wolf. –– New Jersey, USA, 2012.

4. Hashimi Sayed R. Hashimi. Traverse Adjustment Using Microsoft Excel Solver. ACSM/TAPS Conference

April 19 –– 21, Nashville, TN, USA / Hashimi Sayed R. Hashimi, 2004.

5. Odumosu, J. O. Development of an Object Oriented Program for Traverse Computation / J. O. Odumosu,

O. G. Ajayi, P. Ibrahim, V. C. Okorocha, F. F. Idowu // International Journal of Scientific Engineering and

Technology. –– 2014. –– Vol. 3, issue 7. –– pp. 967––973.

6. Ruchel Jan Ruchel. Creating Applications for Geodetic Computations / Ruchel Jan Ruchel // Geomatics and

Environmental Engineering. –– 2010. –– Vol. 4. –– pp. 81––89.

7. Serwa A. Serwa. Detailed Studies of on the Potentials of High Scanning Resolution and Different Types of

Camera Lenses for Digital Photogrammetric Applications, MSc Thesis, Faculty of Engineering, Assiut Universi-

ty, Egypt, March 2003.

8. Serwa A. Serwa. Automatic Extraction of Topographic Features from Digital Satellite Images, PhD. Thesis,

Faculty of Engineering in Cairo, Azhar University, Egypt, Sept. 2009.

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