Physical Measurement

This ground method involves physical measurements of the units or parcels of land on the ground using measuring tapes. The material and preparation needed are as follows.

Materials required include a compass, measuring tape or chain (30-100 m), hammer, survey pegs, permanent-marker paint, clinometer (ocular device showing changes in percent and in degrees), shovel and notebook

Preparation for fieldwork Good knowledge and information on existing data from the area, a person with local knowledge in the team, permission from landowners and land users obtained by explaining the work's purpose and maps available for the area.

If the land is leveled, the area can be measured by using a tape or chain and compass. If the site has a significant slope (greater than 10 degrees), a clinometer should be used to record the slope in degrees. This is done by taking a clinometer reading from one position to the next, ensuring that the next location is at the same height as the operator's eyes. If the slope is greater than 10 degrees, a correction factor has to be used for estimating the distance, which can be done with a correction table given in Table 8.2. Two people make the work easier (Greenhouse 2002).

The choice of a distance-measuring device should be evaluated based on where it will be used. Dense or thorny environments will destroy a regular measuring tape and thick vegetation will entangle it, hence a chain is required. In open grassland areas, a measuring tape made of fibreglass is preferable, since a fabric tape may expand since it is slightly elastic and should therefore be avoided. Metal tapes are available but usually in short lengths.

Table 8.2 Distance slope correction table

Slope percent Slope distance per 30 m

30.1

30.3

30.8

33.8

34.4

8.2.1.1 Steps in Physical Measurements

Step 1: Hold or tie the measuring device at a fixed point along the border of the land area. Tag the starting point and all the points on the boundary whenever the direction changes for periodic monitoring. Tagging can be done with metal clips that are added to trees or other permanent features.

Step 2: Take a bearing to a point on the boundary in the direction in which you will be walking.

Step 3: Walk towards the point where the bearing was taken letting the measuring device unfold as you walk.

Step 4: At each change of direction, record the covered distance using the measuring device.

Step 5: Check the previous bearing with a back bearing and record it.

Step 6: Take a new bearing to the next point.

Step 7: If the slope is greater than 10 degrees, measure this in degrees with a clinometer at every change of direction.

If available, digitalize the result into a geographical information system (GIS) since it can be easily stored, changes incorporated and linked to other data for the project.

Map, either manually or digitally, the spatial distribution of different parcels of land, locations of the parcels, project activities along with the boundary and extent of each parcel of land.

8.2.1.2 Merits and Demerits of Physical Measurement

• Provides ground knowledge of the project area to the project managers

• Easy to adopt and local staff could be trained to implement the method

• Suitable for projects covering small geographical areas

• Suitable for project proposal development phase

Merits

Demerits

• High cost, particularly for large areas

• Difficult if there are multiple land units far apart

• Not suitable for large sized projects

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

Get My Free Ebook


Post a comment