Brunton GEO Transit Instructions

Locate the area you wish to survey on a base map or aerial photograph. Use the highest resolution or largest scale maps and aerial photos you can find. Sketch out the rough boundaries of your study area on the map and observe any substantial landmarks such as buildings or roads, streams, hilltops and mountain peaks. Transcribe the site boundaries and main features from the maps and aerial photos into your field notebook.

Go to your study area and select a permanent object such as the corner of a building, corner of a bridge or the center of a manhole cover for your first point. If there is a geodetic survey benchmark on or near your study site, use it as your base point. Label the point on your field sketch map and in your notes.

Adjust the magnetic declination dial for your specific declination between magnetic north and true north for this and all subsequent measurements. Hold your geo transit waist high in front of you and take general azimuth directions in degrees from the compass for several visible landmarks or features.

Use a handheld GPS (Global Positioning Satellite) unit to determine the precise latitude and longitude coordinates and elevation of your base point. Compare with a topographic map for accuracy. Once you have characterized your first point, label, list and record latitude, longitude, elevation, and direction of travel for each subsequent point you measure. Record data point by point in your field notebook.

Take sight of your next feature, objective or point. Use the small right-angle sight at eye level with the long pointer sight in front in the direction of interest. Take directional data on visible points at each new data point. Record all point data and in-between point data, such as distance and slope, on your field sketch.

Measure the slope of your path to the next object or point by employing the clinometer function of the pocket transit. Hold the transit on its side and face toward you. Level the bubble and your transit is now a clinometer, which measures the number of degrees or the percent grade in a slope. Look through the viewfinder to observe and then record the slope. Use this information to create or to compare topographic contour maps.

Place your pocket transit on a sloping surface of any kind and measure the level horizontal strike direction and dip angle perpendicular to strike direction. Use this on near vertical walls and heights that you can not traverse in their entirety as well as on exposed beds of rock and earth materials. Use a tape measure to measure the distance to the base of an object and use your clinometer to measure the angle toward the top. On level ground, Height = (TanA + TanB) x Distance. On sloping ground, Height = (TanA - TanB) x Distance.

Create a final map showing features you observed and using the field data you collected with your Brunton pocket geo transit, GPS unit, and tape measure. Take your finished map back into the field and test it for accuracy by using your Brunton pocket transit to measure and locate features from the map in the field.