The lab exercise for my Maps and Mapping class on Friday was surveying using a theodolite (transit) and a survey stadia rod. We had to survey a number of different types of geographic features in the quad near our building.

We took measurements for two polygons (a garden, and the concrete pad for a large sculpture), two lines (a road segment, and the side of one of the buildings on the quad), and five points (lamp posts).

There are five values collected for each sighting:
1. horizontal azimuth
2. vertical azimuth
3. lower stadia height
4. crosshair height
5. upper stadia height

A polygon needs a minimum of three sightings. A line a minimum of two sightings, and of course a point just needs one sighting.

There is a spreadsheet they gave us to enter our measurements. This will calculate distances from the central control point to each sighting location. (We did not move the theodolite for any of these measurements.) We will then use these points to construct a map of the quad. I had to stop by Office Depot to pick up a protractor. That, and a calculator, is the only thing I will need to get the points properly onto my map.

Pretty neat stuff. I have also wondered how surveying worked. I think it would be neat to find an antique theodolite at an estate action or flea market. I would also like an antique sextant.