ERRORS IN PLANE TABLE SURVEYING

ERRORS IN PLANE TABLE SURVEYING

The errors could be grouped into the instrumental in addition to personal errors.

Instrumental Errors

1. The outer lining of plane table not flawlessly plane.
2. Bevelled edge connected with alidade not straight.
3. Sight vanes of alidade not perfectly perpendicular on the base.
4. Plane table clamp currently being loose.
5. Magnetic compass currently being sluggish.
6. Drawing sheet being of low quality.

Personal Errors

1. Centering errors
2. Levelling errors
3. Positioning errors
4. Sighting errors
5. Problems in measurement
6. Plotting errors
7. Errors due to instability of tripod.

ADVANTAGES AND DISADVANTAGES OF PLANE TABLE SURVEY

Strengths are

1. Possibility of omitting measurement is eliminated.
2. The surveyor can compare the plotted work within the field then and there just.
3. Irregular objects are plotted a lot more accurately, since they are viewed while plotting.
4. Booking errors are eliminated.
5. Local attractions usually do not influence the plotting.
6. No great skill is instructed to produce satisfactory maps.
7. Approach is fast.
8. No costly instruments are needed.

Limitations are

1. Survey are not conducted in wet weather in addition to rainy days.
2. Plane table is cumbersome and heavy to handle.
3. It needs many equipment.
4. It is less exact.
5. Reproduction of map in order to different scale is difficult.