HW Set up Your Project Site, Measure Distances, Sketch Site

HW Set Up Your Project Site, Measure Distances, Sketch Site

Site: You are to establish a “survey site” consisting of a four-sided "parcel" with four "corners" near two geodetic control points. Much of our course homework will be associated with this site.

Your location must be carefully chosen – somewhere that you will have access in a safe environment (away from major roads, etc.) Start by searching for geodetic control points with vacant land nearby that you can measure on without objection from the owner or authorities: school property, airport perimeters, county/city properties, etc.

Do the following:

1. Find two inter-visible horizontal control points. View the Lecture on NGS control. This lecture discusses NGS control points and how to find them, including dominant web sites of control point information. The one closest to your parcel will be called the "base control point". The other will be called the “backsight” point. The straight line between these will form a “reference azimuth”, a line of known direction. As an alternate, you may find one control marker with an “azimuth mark” so that the direction from the marker to the azimuth mark is published and known. As another alternate approach, you may be in an organization that has high-accuracy GPS survey ability. The organization may be able to establish two control points for you.

2. Establish your “parcel” near one of the control points. This control point will be your “base control point”, the one you’ll use to geo-reference your parcel. The parcel should have the following attributes:

a. Set four markers to create a four sided "parcel". You need to have a physical marker that gives a well defined point for measuring. Surveyors usually set reinforcing rods with plastic caps driven flush with the ground surface. The cap has a well defined “dimple” that indicates the precise corner. Alternatively, you may get large nails from a hardware store and push these into the soil to define the corners. Tie plastic “flagging” on the rods or nails before you set them to aid in their recovery. Don't leave the tops of your markers above the ground surface. The parcel corner closest to the "base control point" will be called the "reference point."

b. The sides of the parcel should not be less than 150 ft and not more than 300 ft long. The sides should not be parallel.

c. The nearest edge of your parcel may be located close but not at the base control point.

3. Measure Distances on Your Parcel

Equipment: Total Station Theodolite

Procedure:

Parcel Measurement with Total Station -- Beginning at your parcel's reference point (closest to the base control point) measure distances around the parcel, measuring all sides forward and backward along with the diagonals forward and backward. Also measure from the parcel's reference point to the base control point. Always record the reduced horizontal distances (H), not slope distances.
Record total length of each line in field book to nearest 0.001 ft or millimeter.
Measure each line in the reverse direction.
Calculate the discrepancy ratio (shows how precisely you made your measurements) and express as a fraction:

ratio = | FWD. DIST. - BACK DIST. |

AVERAGE DIST.

Determine acceptability of each ratio. Your ratio should be < 1/5000 or the denominator of your fraction should be > 5000. If the calculated ratio is NOT acceptable, then re-measure the line forward and backward.

4. AutoCAD Sketch your Parcel and Site

Gain access to mapping software – download from Autodesk Inc., gain access at a surveying/engineering firm, high school, community college, university laboratory, etc. Watch the lecture video on ACAD Intro Sketching, mastering all the ACAD techniques demonstrated.

Prepare a sketch of your project site. Input your geodetic control points in State Plane Coordinates. Sketch other features such as: nearby roads, buildings, sidewalks, parking lots. Enter your parcel corners as point input, clicking the screen for the approximate location. Add lines around your parcel, the tie line to the base geodetic point, and the line to the backsight geodetic point.

Add appropriate labels in text. Add a north arrow.

Save your drawing. When doing the "save as", in the save as dialog box, pull down the list of "file types". Select ACAD 2007. This will allow grading with older or newer versions of AutoCAD.

Submit: In the WebCT Assignment tool for this HW, upload

1. An Excel spreadsheet that is set up to resemble a field book. Include all typical field book content in the spreadsheet: page title, personnel, date, weather conditions, sketch of parcel and surrounding features, notes of markers set, control point locations, north arrow, etc. You can make the sketch in your spreadsheet using the Drawing Toolbar as demonstrated in the Trig Review lecture.

2. Attach your ACAD 2007 *.dwg file to your WebCT upload.

Also, incorporate the following information in your Excel spreadsheet concerning your two geodetic control points, similar to the following:

1. Complete the following for your “tie” control point:

Mark Name:TIGERT RESET

Mark PID (if NGS):AR1389

Mark physical construction

(brass disk, rod and plastic cap, nail,

other - explain):BRASS DISC IN CONCRETE

General Location (describe):ON UNIVERSITY OF FLORIDA CAMPUS NEAR AUDITORIUM ALONG UNION DRIVE.

SPC State Plane Coordinates on the NAD83 datum (express in feet):

Northing =3,280,718.516

Easting =370,055.093

Method used for coordinates

(NGS published, locally measured - explain):NGS PUBLISHED VALUES ON DATA SHEET

2. Complete the same information for your “backsight” control point:

Mark Name:TIGERT AZ MK 2

Mark PID (if NGS):CW5172

Mark physical construction

(brass disk, rod and plastic cap, nail,

other - explain):BRASS DISC IN CONCRETE

General Location (describe):ON UNIVERSITY OF FLORIDA CAMPUS NEAR LIBRARY WEST

SPC State Plane Coordinates on the NAD83 datum (express in feet) AND/OR Azimuth from north:

Northing = none given

Easting = none given

Azimuth = 332 26 57.3 (ddd.mm.ss)

Method used for coordinates

(NGS published, locally measured - explain):NGS PUBLISHED VALUES ON DATA SHEET