FROM TAPE TO SPACE – Fundamentals of spatial measuring: Part 3 – Measuring Tools

Generally, the following shall be in the pack of instruments if you are to measure a site, which makes your measuring more easy and accurate.

Measuring Tools

• Conventional measuring tapes
• Self-retracting tape measure (or pocket tape measure)
• Long Distance tape measure
• Measuring Wheel (Optional – used to measure large lands)
• Steel ruler
• Laser Measuring Tape
• Large profile gauge
• Angle Compass

Other Tools

• Clipboard
• Tracing Paper / Graph paper (Preferable)
• Pens and Pencils including clutch pencils
• Flashlight
• Camera (More than 5 MP is preferable)
• Calculator
• Spirit Level / Level Tube (Optional, but comes in handy on special situations)

2.1          Self-retracting tape measure (or pocket tape measure)

There are many variants of this type of tape measures. However, for the purpose of architectural measuring, it is best to use a Professional type Magnetic (Where the hook is magnet which helps on securing it on steel objects when taking measurements) tape measures. These shall include the following features:

2.1.1      True Zero Design

Tape measures comes with a hook on their free end which enables you to fix the hook to take measurements. however, to its own structure, this type of end assembly introduces an inaccuracy when the rule is used for inside measurements. I.e., if the tape starts exactly at zero, then taking the measurement adds the thickness of the hook, which requires you to deduct its thickness from the measurements.

True zero enables you to take measurements directly without doing any math. This is done by allowing the hook to move back and forth along the securing rivets to account for the hook design thickness and provide an accurate measurement.  If you count the marks on the first 1″, you will notice a shortage of 1/16″ – 1/8″. (i) Push the hook all the way in for an inside measurement; e.g. interior of a cabinet. (ii) Pull the hook all the way out for an outside measurement.

Figure 2 – Tape Measure TrueZero Feature (Source – http://diyhousehelp.com/wp-content/uploads/2012/05/tape_measure_true_zero.jpg)

2.1.2      Scribing Feature

Helpful in locating where you want to screw, nail, drill, or cut if a pencil is not available or easily available. Place the tape measure at the edge of the material, at the measurement wanted, let’s say 17″, then place the blade tip and mark the material where it needs to be cut. To achieve this, tape measures comes with a saw tooth edge on the hook.

Figure 3 – Tape Measure Scribing (Up) | Saw tooth edge of hook (Down)

2.1.3      Nail Grabbing

Use the slot to latch onto a nail or screw head, for help in measuring or drawing circles. (i) When drawing circles you will be better served to have a tape measure with a very secure locking mechanism. (ii) When trying to keep the blade hook taught on the nail or screw head, you may tend to pull on the body, which can easily move with a weak blade lock, and therefore ruin your measurement and drawing. (iii) Use the same scribing procedure mentioned above, with the pencil tight against the body and exact measurement.

2.1.5      Body Dimensions

The majority of tape measures, minus flexible tape diameter designs, will have markings on the tape measure body. This aids in taking accurate inside measurements; e.g. inside cabinets, wall corners, or any other place that would have you bend the tape to get a full measurement. Butt the tape measure body up to a wall, edge, etc. and add the body measurement to the blade measurement. Some bodies have more visible markings than others. You may have to look closely or lift the belt clip to properly see on some brands and models.

2.2          Laser Measuring Tape

A laser tape measure is a very simple device and a great technological advance on the old way of measuring distances. It is accurate to within 1/8 inch up to 300 feet and can measure distances up to 650 feet in some instances.

Usually best brands of laser measures are expensive, equipped with high accuracy and they offer many other features. There are cheap Chinese brands where the accuracy cannot be guaranteed.

If you plan to use such device, always think about the quality and accuracy of the device because inaccurate readings will ruin the entire measured drawing and your designs (especially in renovation projects).

2.2.1      Using a target

As long as the laser optics can hit something, you usually won’t need a target when measuring distances less than 100-300 (depend on model) feet with your laser tape measure.  Go beyond that and a reflective target is necessary in order to obtain a measurement.

2.2.2      Measuring

Just place it with the base against an object and aim the laser dot at the other object whose distance you want to know. Press the button marked “measure” and you’ll immediately have a readout of the distance. Some instruments will offer a choice between metric and inch readouts.

2.2.3      Additional Features

A good laser tape measure will come with addition and subtraction keys. Some allow calculation of floor areas, volumes and some offer more sophisticated features like producing CAD format drawings according to the measurements.

2.2.4      Long Distance Outdoor measuring

When you’re measuring longer distances in sunlight, you can have problems seeing the red laser dot on the far object. That makes it impossible to know if you’re measuring the right distance. If you’re doing this kind of work, use a magnified view finder which is usually available on some models. Others have an optional external view finder that can give even greater magnification of up to 4x.

2.3          Measuring Wheel (Surveyor’s Wheel)

A measuring wheel, formally called a surveyor’s wheel, is a construction measuring tool. The origin of the measuring wheel dates back the 17^th Century alongside the evolution of the odometer. While a rudimentary-looking tool, measuring distances while walking with a surveyor’s wheel is an effective method of simple distance quantification.

The more flat the surface being traveled along, the more accurate your measurement will be. Elevation changes, rough or soft terrain, or ground debris can affect the measurement. Accurate surveyors will compensate for such circumstances by estimating or using surveyor’s tape. Measuring wheels are used largely used for lower accuracy measurements – which is to say, they’re used to get idea of how long a given distance is or used for distances where surveyor’s tape alone would be impractical.

The measurement can be taken by using the formula:

Measurement = 2 * p * r * n

p – Pi value constant = 3.14159

r – Radius of the wheel

n – Number of revolutions

2.4          Profile Gauge

A profile gauge or contour gauge is a tool for recording the cross-sectional shape of a surface. Contour gauges consist of a set of steel or plastic pins that are set tightly against one another in a frame which keeps them in the same plane and parallel while allowing them to move independently, perpendicularly to the frame. When pressed against an object, the pins conform to the object. The gauge can then be used to draw the profile or to copy it on to another surface.

In architectural conservation, they are used to document the profiles of decorative moldings.

Once you have recorded the shape, you can easily transfer the shape into a 2-D paper space where you can manipulate it further.

2.5          Angle Compass

Angle finder tools and protractors can be used in a variety of different settings. They offer a great solution to finding precision angles and degree of bend with ease. Especially finding angle of slanted walls, etc. You’ll find stainless steel, aluminum, plastic, and lexan gauges in an assortment of different sizes, both rotational and digital.