One of my Wednesday classes is a
3-hour long surveying lab. Though long, this lab is pretty cool! As of a couple
weeks ago, we only learned how to use the equipment (levels, theodolites, total
stations); but that's pretty neat right there. A couple weeks ago, though, he
told us he was going to have us form groups and do a topographic survey.
A topographic survey, in case you
don’t know, is a survey where you locate all the existing features on a portion
of land. Usually, topographic surveys cover a large amount of land, but for the
purposes of this class, we only surveyed a small portion (about 20’ by 40’). Here’s
a picture of the area we surveyed:
 |
| The red square is the area we surveyed. |
In order to locate the points, we
had to set up a total station (an instrument that can measure angles and
distances electronically) on a control point, then calculate azimuths (the
angle from one point to another), horizontal distances, and vertical distances
for each point in the field. So, the total station never moves, but another
person moves around with a prism (set on a rod), and sets the prism directly
over each point, whether it be the side of a tree, a bush, a sprinkler, an
electrical box, or a side of a concrete border. Then, once one point is
collected, another point is calculated, and so it continues until all the
points are in the book and written down. All told, we calculated over 60 points
(61, if I remember correctly)! Here’s what my sheet of points looks like, in
digital form:
CRB1 102.691883382503 142.995815655189 10.02
SHR1 103.698409334966 144.125278111203 9.98 Also ICRB1
SHR2 108.325346748989 144.406317135168 9.7 Also ICRB2
SHR3 110.228469841332 146.774702614821 10
SHR4 111.955910512808 151.305346737058 10
SHR5 110.473243755337 154.238074866659 10.02
SHR6 107.619548986577 155.559957462557 10.04 Also CA1
SHR7 103.297639062727 155.442016346919 10.04
CB1 103.539463355811 156.529300359662 10
CB2 104.895894984577 158.816584500462 10.06
BOX1 103.792614195121 153.746353155977 10.06
BOX2 105.171469810285 151.64170698187 10
CA2 106.065398014763 156.797054033836 10.14
CC1 107.711169979565 157.545646729759 10.1
CC2 106.484224060766 159.085264138614 10.1
ICRB3 103.045059763272 161.965225820924 10
OCRB2 101.862886422586 162.952442797532 10.14
SHRA 110.625501476061 160.757889350949 10
SHRB 113.909296203132 157.522203357778 10.04
SHRC 114.543777938458 154.037025485095 10.1
SHRD 114.574863695737 149.936497156395 10.02
SP1 113.782690061931 144.682603490136 10.14
OCRB3 123.692964668298 144.05273913421 9.98
ICRB4 123.704000493175 145.021047973359 9.76
TR1 120.511746826358 150.514340955133 10.12
TR2 118.779897362706 151.970982817782 10.16
TR3 121.568953722249 151.852925041192 10.06
SP2 123.049012244016 154.050722794198 9.98
ICRB5 123.023207559912 163.026517543437 9.7
OCRB4 121.999711752923 164.300655383816 9.8
SP3 112.876610303107 162.364535652099 10.14
TCRB1 128.916913713065 162.758442470405 9.84
TCRB2 129.629165614072 148.951414126804 9.88
SP4 123.531017525889 145.134257656422 9.94
SP5 122.609335507697 162.751158936711 9.96
SP6 103.282508299612 161.933073064906 10.2
CD1 96.7763558407172 162.697181103574 10.2
CD2 94.3965415455412 158.994481549965 10.12
OCRB5 93.6782036427429 159.203433099926 10.06
ICRB6 92.7324544480534 159.054489936417 9.92
BSH1 90.1407732019041 159.488533743434 10.04
SP7 88.8585514210008 161.498927824487 10.42
BLD1 87.8435736152824 161.204422205858 9.88
BSH2 91.3222946390717 155.18185417027 10.24
BSH3 90.2644251432568 150.591787695324 10.22
SP8 89.379011805599 151.557387538299 10.62
BLD2 88.122347767295 150.728013734414 10.02
BLD3 78.2882772902315 150.228273880098 10.42
MC1 80.7812348117533 145.746950331569 10.42
MC2 83.9317739053884 145.485269155766 10.36
MC3 82.4024570970866 147.078594751544 10.38
BLD4 78.6398380084268 141.978011859708 10.1
OCRB6 88.508122312508 142.265550359787 9.84
ICRB7 88.5138942841599 143.468045452775 9.84
SP9 91.6413341011986 143.870813810462 10.2
ICRB8 93.3754742731745 143.599606178206 9.94
OCRB7 94.541074072439 142.692408314798 10.02
SP10 94.4806821742037 147.238657164846 10.28
SP11 94.0733334072462 156.40951181404 10.24
HOL1 104.974881767206 160.114498678791 9.78
HOL2 109.110867393118 144.517251659834 9.72
It may look like a bunch of jibberish, but this list of
points tells me the x- and y-coordinates of each point that we surveyed in the
field, as well as the elevation at each point.
After the long process of taking the points in the field,
and reducing them down to coordinates and elevations (a job that took about 5
hours total), I was ready to input them into AutoCAD and actually create the
map. The professor was originally going to make us do it by hand on a gridded
sheet of paper, but he said he was fine with AutoCAD drawings, as well. I
immediately jumped on that, since AutoCAD drawings are cleaner, more professional
looking, and more accurate than hand-drawn ones. Besides, AutoCAD is what most
companies use for topographic survey maps anyway!
This drawing was different than my other drawings, because
this one I did completely from scratch. The other ones I’ve done I’ve just
copied other drawings. As you can imagine, I’m proud of this one J
So, after another few hours of work on AutoCAD, I finally
put the following image together (it's oddly squashed, for some reason):
And there you have it! A topographic map, from start to
finish!
