A scale is a ratio that increases or decreases the size of an object, drawing, or model. It is important to work with scale rulers to help avoid mistakes.
This systematic review identified ten main types of limitations commonly reported during the scale development process: sample characteristic limitations, methodological limitations, psychometric limitations, qualitative research limitations, missing data, social desirability bias, item limitations and lack of manual instructions.
Definition
A series of steps or degrees representing a ratio of relative size. In geography, scale refers to a map representation that preserves the relationships of distances and areas between locations, depending on a specific scale ratio.
The scale of a map is an important factor in how well it will work. For example, if the scale of a map is 1:1,000,000 then each pixel on the map will represent one kilometer on Earth’s surface. This is a very useful feature, especially when trying to find the location of an object on a large area map.
The term “scale” is often used by people who produce and use geographic information, and it has many different meanings. If you’re new to the field, it can be confusing to keep track of all these different uses. The purpose of this chapter is to help you understand the different concepts behind scale and how they relate to map creation.
Types
There are four different types of scale. They are nominal, ordinal, interval and ratio. Each level of data measurement has a different impact on the statistical analysis you can perform. It is important to understand how a measurement scale works before using it in your research.
The first type of scale is a nominal scale. It names groups in your data, but doesn’t provide any numerical value. For example, a scale of “high school, college, and post-graduate education” is a nominal scale.
Another type is an interval scale, which records continuous data and allows you to make comparisons between data points. For example, the Celsius and Fahrenheit temperature scale is an interval scale.
Ratio scales are often used to measure quantitative variables, such as height, weight and speed. They can be continuous or discrete, and can include a zero measurement that indicates a lack of the characteristic. For example, a ratio scale that measures a variable such as weight may use a decimal point for precision.
Units
The units of scale are the measurable quantities that form the basis of a measurement system. These are called base units and consist of the metre (m), kilogramme (kg), second (s), and Kelvin degree (deg).
Other dimensions can be defined as derived units by combining base units. For example, the derived unit for area is the square metre. A derived unit is a named combination of base units that have been officially accepted by the International System of Measurement, or SI.
The SI prefixes for each unit of measure are arranged from largest to smallest. This makes it easy to remember the conversion factors for each unit. For example, when converting meters to centimetres, the conversion factor is 100. This same convention is used when converting between the metric and imperial systems of measurement. The pound is a common unit of weight in the UK, and pounds are commonly used in health and fitness centres to monitor personal weight.
Measurement
Scales of measurement are important to understand before selecting a technique for data analysis. There are four types of scales: nominal, ordinal, interval and ratio. Each has a set of properties that determines how the data can be analysed. The ratio scale, for example, has properties like identity, magnitude, equal intervals and a meaningful zero point.
Other examples of scales include the Likert scale, which uses adverbs of degree to rank a list of attributes, and the logarithmic scale, which is used for things like distances and temperatures. Using a scale when drawing or creating something helps people interpret the size of objects accurately based on their representations.
The scale of a map can vary depending on the curvature of the Earth’s surface, which can affect the distances between locations. This can be corrected by using a conformal projection. Alternatively, Tissot’s indicatrix can be used to show how scale changes across a map. Error bars are graphical representations of the uncertainty in a measured value and can help determine how accurate a measurement is.