November, 03, 2015

ESSE 2620Lab Report #8

Topographic Map

Group Members:

Dania Al-Adhami 213843883

Mark Umansky 213542527

Faisal Hamdan 213640057

Saman Imani 211292174

Josh Karon 213374137

Purpose:

The purpose of this lab is to practice topographic surveying. A map is created using a series of measured points taking into account the zenith angles as well as the slopes to each point from the reference. To have an accurate map, many points need to be at any topographic features such as roads, pathways, trees, and buildings.

Materials:● Tripod x1● Total station x1● Prism x1● Pole x1● Measuring tape x1

Methodology:1. A strategic point was chosen to be the location of the total station.

From this point, it was easy to locate the boundaries of the given area and all the points within it.

2. The total station was set up at the point chosen above and was leveled accurately.

3. The height of the total station was measured with the tape.4. An orientation point was chosen at a known location. It was sighted

and the readings were set to zero.5. A new unknown point was chosen next and the prism and pole were

set up and leveled there.6. The prism was sighted and the measurements of horizontal and

vertical angles were recorded.7. The prism was moved to another point near the point above.8. Steps 5-7 were repeated many times within the given area at

different points.

Raw Data: Table 1.1 Horizontal Angle Measurements and Distances

Point Name degrees minutes seconds Distance (m)

1 (BS) 0 0 0 30.2592 9 21 9 27.4603 3 59 8 24.6454 352 12 29 22.7565 336 13 15 20.946 260 56 53 38.7217 263 21 50 39.1048 268 35 55 35.9019 272 30 6 31.156

10 277 24 19 36.51411 279 10 27 40.12712 283 34 29 50.23213 322 3 39 39.16114 334 38 34 39.83415 343 59 10 40.53916 351 10 9 41.24117 357 9 46 40.63518 0 9 24 41.99419 11 53 32 30.47620 244 49 51 32.36721 335 38 2 25.94522 318 41 46 29.58423 310 20 36 26.24024 306 2 48 23.93125 293 45 1 23.93126 254 12 46 32.67927 336 58 21 14.31928 0 17 8 16.22929 21 17 37 17.23530 4 22 53 10.82931 278 53 31 10.20032 247 40 15 25.47333 254 27 38 26.77234 286 31 22 13.42835 25 53 14 11.40536 337 0 19 5.28637 241 28 41 25.255

38 231 48 29 24.73639 231 33 48 14.51440 251 9 50 8.376

Table 1.2 Vertical Angle Measurements and DistancePoint Name Degrees Minutes Seconds distance

(m)1 (BS) 91 22 29 30.259

2 91 34 15 27.4603 91 48 49 24.6454 92 1 4 22.7565 92 15 0 20.9406 91 48 47 38.7217 91 47 23 39.1048 91 34 13 35.9019 91 3 5 31.156

10 89 38 4 36.51411 88 33 26 40.12712 88 0 4 50.23213 88 12 58 39.16114 88 44 57 39.83415 89 38 24 40.53916 90 38 8 41.24117 90 44 12 40.63518 90 45 59 41.99419 91 25 4 30.47620 90 52 43 32.36721 91 25 46 25.94522 90 4 1 29.58423 90 48 4 26.24024 92 8 22 23.93125 89 56 30 23.93126 91 56 15 32.67927 93 19 17 14.31928 92 45 31 16.22929 91 57 39 17.23530 92 2 14 10.82931 92 0 42 10.20032 90 12 27 25.47333 91 55 8 26.77234 93 21 11 13.428

35 91 45 25 11.40536 94 26 44 5.28637 90 14 6 25.25538 88 11 1 24.73639 88 20 43 14.51440 93 40 11 8.376

The potential points we were supposed to do (marked in yellow): Figure 1.0

The points we ended up doing (marked in red):Figure 1.1

Calculations:The first step of the calculation process was to convert the measured angles from

minutes and seconds to a decimal in order to perform additional calculations:

degrees+minutes60

+ seconds3600

=degrees (decimal form)

for example measurement 2:

9 °+ 21 '60

+ 9 ' '3600

=9.3525 °

All of our measured angles are in reference to our chosen back site, in order to convert to UTM coordinates we need to find the offset of our angle measurements from the conventional Northing Easting axis.

θ=tan−1(∆ x∆ y

)=tan−1( TS easting−BSeastingTSnorthing−BSnorthing

)=22.3633477 °

For example measurement 2 now becomes:

9.3525°+22.3633477°=31.71474779°

To find the ∆x and ∆y of each point in reference to the total station use the equations:

∆ x=distance×sin (θ+180 °)∆ y=distance× cos(θ+180° )

For example measurement 2:∆ x=27.46m×sin (31.71474779°+180 °)=−14.435465m∆ y=27.46m× cos(31.71474779 °+180 °)=−23.359558m

Finally the UTM coordinates can be found for each point by adding the ∆x and ∆y to the known location of the total station:

point Easting = TS Easting + ∆xpoint Northing = TS Northing + ∆y

point 2 Easting = 619860.654m - 14.435465m = 619846.219m Eastpoint 2 Northing = 4847847.221m - 23.359558m = 4847823.860m North

To calculate the elevation of each point first convert the measured azimuth angles from minutes and seconds form to decimal form (equation provided above). Then use the following equation to find the ∆h:∆ h=distance ×sin(ϕ)+(TS−R)where TS is the total station height and R is the rod height

For example point 2:∆ h=27.46m× sin(90°−91.570833333° )+(1.560m−1.45m)=−0.642754918

Finally add the ∆h to the known elevation of the total station:UTM height = UTM height + ∆h

for point 2:UTM height = 191.149m - 0.642754981m = 190.502245m

Calculated UTM Coordinates:

Point Name UTM N (m) UTM E (m) UTM height (m)1 (BS) 4847819.2376 619849.1416 190.52905252 4847823.8614 619846.2185 190.50224513 4847825.1362 619849.7161 190.4750301

4 4847825.1968 619854.9293 190.45377065 4847826.2874 619861.1718 190.43289956 4847838.3065 619898.3349 190.02992537 4847836.6223 619898.2943 190.03372488 4847834.3781 619894.1793 190.27120189 4847834.1210 619888.9221 190.683313310 4847829.0925 619892.3499 191.487963111 4847826.2330 619894.8546 192.265340112 4847817.7401 619901.3250 193.007098013 4847809.4984 619871.1700 192.474070414 4847807.4414 619862.7353 192.124553415 4847806.9306 619856.1715 191.509712416 4847807.1248 619851.0045 190.797542117 4847808.9227 619847.0730 190.732559718 4847808.4289 619844.5708 190.693304619 4847822.0312 619843.5000 190.500951720 4847848.8060 619892.9822 190.758682621 4847821.2919 619861.5612 190.607778022 4847819.2390 619870.2571 191.220434023 4847823.9025 619872.6867 190.888123624 4847826.8364 619873.1903 190.361615725 4847829.9739 619877.2440 191.279364426 4847843.4791 619893.1181 190.150145627 4847832.9030 619860.8203 190.425404228 4847832.2434 619854.4048 190.473926729 4847834.7515 619848.7562 190.665281830 4847837.5504 619855.7810 190.870042731 4847841.9289 619869.3737 190.896949532 4847847.2063 619886.1270 191.162748233 4847844.0405 619887.2364 190.358548534 4847838.7914 619871.1065 190.469616935 4847839.6265 619852.1453 190.905326636 4847841.9353 619860.7123 190.845272937 4847849.9309 619885.7632 191.151416338 4847853.9685 619884.4519 192.039048539 4847851.2397 619874.6005 191.674111140 4847846.7058 619869.0141 190.7188945

Topographic Maps Made Using GIS:

Figure 1.2

Figure 1.3

Discussion:

In this lab we practiced topographic surveying, and the main point of this lab was to create a topographic contour map using a series of measured points. In order to get the required points, we set up the tripod at a strategic location so we are able to easily read the points that we needed. Once the station was set up, it was time to start reading the points, some of team members went around the perimeter of the area that we were reading, and had to decide which point to take and held the prism until the other members got and recorded the needed information. Some of the problems that we encountered during this lab included faulty equipment, where the tripod legs were not locking and we had to get that replaced which wasted about an hour of our time. We also faced an issue with the total station itself as it froze on a screen for almost half an hour and because it was a different type of total station compared with the one we have used earlier it was difficult for us to operate it. Another issue that we

encountered was the light, after the sun went down. It was very hard to see the crosshairs so it was difficult to get the readings. Errors:

As mentioned above, we have had several man made errors, due to the time constraint we have been put into due to our total station not functioning properly. We were not able to make all the potential measurements because we did not have the time to do so as it became very dark to see any measurements. We had to cut down our area into almost half of what the area we had to cover initially. Other errors were due to the movement of the person holding the prism. Thus, measurements kept alternating and once it settled, the measurement was recorded. Using the GIS software also created many errors because none of the team members have enough skills to create a perfect topographic map. Our points on the map in figure 1.3 were shifted to the right although we are certain of the positions of our final measured points in figure 1.1.

Conclusion:

After setting up the total station and acquiring all the needed points, we were able to implement and apply what we learned to do the necessary calculations to construct a contour map using the acquired points and angle measurements. We also concluded that if we acquired more points we would’ve gotten a more precise map.