EA141 SURVEYING 1 GRID LEVELING/TOPOGRAPHIC MAP

The objective of this project is to produce a topographic map of the area surveyed using the grid method.

Class: - 26 chaining pins, 4 range poles, 1 optical squareCrews: - level, rod, cloth tape

- the grassed area west of F-Wing

SURVEY PROCEDURE:

1. The class will set out the 4m x 4m grid. Thereafter each crew will work on their own.

2. Mark the four corners of the grid at stations (0,0), (20,0), (20,16) and (0,16) with the range pole

3. Mark the other grid points with survey pins.

4. Using profile survey format, take IFS readings on every grid point.

5. Then locate (by their co-ordinates) and take IFS readings on any break points (pointsbetween grid stations where the ground slope abruptly changes). These should be described as "breakpoints" on the description page.

6. Finally, locate (by co-ordinates) and take IFS readings if appropriate on any detail features inthe grid space (light standard, tree, maintenance hole and catchbasin). These should also bedescribed and sizes given on the description page. A diagram of the grid should be included.

SURVEY AREA:

EQUIPMENT:

TOPOGRAPHIC MAP (Scale - 1:100)

Each student should produce a topographic map on A4 or 8.5"x11" paper showing the following:

a) grid lines (dashed) with the co-ordinates of the four corners indicated using leader linesb) a note that the grid is 4m by 4mc) the elevation of each grid point on a 45° angled) the elevation of each breakpoint and feature (45° angle) with co-ordinates labellede) a symbol for each detail feature with appropriate labellingf) title block with title (Contouring by Grid Leveling) , scale, student name, date and class codeg) labelled contour lines (solid) at 0.2m interval (197.8, 198.0, 198.2, 198.4)h) a North arrow symbol

Maps can be drafted by hand or using AutoCAD. The following hints are for AutoCAD:

a) Plot from model space to a scale of 10mm = 1m (i.e., 10mm = 1000mm or 1:100).b) Use one of the mono fonts (each letter or number is the same width).c) Enter the elevations using (0,0), (0,4), etc. as the insertion points (text height: 0.3, angle: 45°)

(NOTE: because you're using a mono font, the decimal points will be on a 4m x 4m grid)d) Draw a dashed line starting at the decimal point at one corner going for 20 m horizontally.e) Repeat going 16 m vertically. Use LTSCALE of 0.05 and OFFSET of 4m to create the grid.f) Since the origin of the grid lines is not (0,0), use MOVE,ALL to move the grid and text so that

the grid origin is (0,0). The base point is the origin of the grid; the move-to point is (0,0).g) Use the POLYLINE command to draw the contours by estimating their location. If necessary,

use the FIT option in POLYLINE EDIT to smooth the contours. (Don't use SPLINE as it willpull the contour away from your selected points.)