Measurement Flashcards
What tools do you measure with?
Laser/disto
Trundle wheel
Scaled plan
Promap
Tape measure
In what instance would you use a laser, tape measure, trundle wheel, OS map + promap?
Laser – when measuring a residential property
Tape measure – use for narrow areas or if bright light, shiny surfaces was affecting laser measurements
Trundle wheel – use to measure site boundaries
OS map/pro map – use to measure site area
What is Promap?
Software used to measure land area
What should be done before calculating the site area on Promap?
Check boundaries on site with OS plan + land registry title document
How do you know where a site boundary is?
Land registration
Title
Fencing
Why do you have to reference to title plans?
To ensure boundaries are correct
Why can measuring software be inaccurate?
Hard to pinpoint the exact boundaries or surfaces to measure online
What are the limitations of a laser measure?
Does not function well in bright light
Less accurate over distances up to 200m
How does a laser measure work?
Measures how long it takes the laser pulse to be reflected from a surface
How would you know if your laser disto needs calibrating?
Would show an error message
However, would always send device to be calibrated annually + regularly check it against known distances
Tell me about a strength and weakness of a measuring technique you have used
Laser/disto
Accurate + easy to use
However, does not function well in bright light + less accurate over distances up to 200m
When would you use a tape measure?
For narrow areas
When would you use a trundle wheel?
When measuring land boundaries
What could be used to measure the boundaries whilst on site?
Trundle wheel
What are the limitations of a trundle wheel?
Human error affecting accuracy
Does not account for changes in level
Can be inconvenient to use
How do you measure a development site?
Promap (remember to check boundaries accurately on site with OS plan or Land Registry documents)
Trundle wheel
What would you require on a HM Land Registry compliant plan?
Correct scale (1:1,250 – 1:500 for urban properties, 1:2,500 for rural properties)
Scale bar
Red line boundaries
Orientation - north arrow
Details including buildings, roads, access points
What is the accuracy of a laser?
Accurate to within 1.5mm
Less accurate over distances up to 200m
What tolerance of accuracy is generally acceptable?
+/- 10%
How do you calibrate a laser?
Send it off to manufacturer to calibrate it annually
Regularly check it using a known distance (do this approx. 10 times + must be within 2mm)
Do you need to calibrate a disto?
Yes – need to be checked annually (send off to manufacturer)
Can also regularly check it using a known distance (do this approx. 10 times)
How do you confirm a laser measure is correctly calibrated?
Check accuracy against a known distance + record on a log
How can you ensure accurate measurements?
Take several measurements
Check with scaled plans
Use tape/rod for tight areas
Ensure disto is calibrated
Why do you take check measurements?
To ensure accuracy before reporting to my client