# What is Scale Bar?

## What is Scale Bars?

A scale bar is a graphical representation of distance on a map. It is typically used to measure the actual distance of a given point on a map, as well as the scale being used.

The length of the bar is proportional to the value on the x-axis; it is typically drawn from left to right for horizontal maps or from bottom to top for vertical maps.

For example, if a map has an x-axis with values ranging from 1 – 10, we could use a 4-inch (ten cm) scale for measuring distances. As the distance between two points increases, so does the length of the scale bar.

Scale Bars are most commonly used with a map of a small area.

They are also used when the values on the x- or y-axis vary widely and it is necessary to show that change.

## Styles and Design of Scale bars

Scale bars/lines come in a variety of styles that can be used in maps. Among them are:

### Simple Scale Lines

A simple scale line is one in which there is a single line with no pattern or other design, just straight lines.

It is used when the scale is constant, and the distance on the x-axis doesn’t change over time. The closest example we can use for this would be a scale bar on a road map.

### Single Division Scale Bars

A single-division scale bar is one in which there is a line on the map that has a “1” or some other single-digit number along the length.

It is used for maps where distances between points are measured in thousands of feet, miles, or the like.

For example, if we used this scale bar with a map of an Olympic bobsled race track, then every time we went around one turn on the track (assuming there was an even number of turns per lap), we would measure 4.0 m to represent the entire length of the track.

In this case, there is no value on the x-axis, so we could use a scale bar that was 5 m long for all the distances between laps.

### Alternating Scale Bars

An alternating scale bar is one in which the value on the x-axis changes from one point to another.

This type of scale can be used for any distance that varies in the x-axis, such as an oil pipeline map with a 100-yard (91 m) route.

It is used when there are no other styles of scale bars that seem appropriate. It is also used in maps where the values along the y-axis are not very important, such as road maps where every mile is a different color.

### Stepped Scale Lines

A stepped scale bar is one in which the line has a step pattern along the length of the line.

This is used to show distance on maps where different values are measured between points. For example, in a map that has steps of 0.5 km, 1 km, and so on, we can use this style to show how many miles there are between each step.

### Hollow Scale Bars

Hollow scale bars are popular in satellite maps because of their carto-friendly appearance. They are used in maps where the values along the x-axis or y-axis do not vary throughout the map.

They are also commonly used with polar maps, where all values along the x-axis and y-axis (and sometimes z) stay constant, such as a map of levels of sea ice. CartoCSS supports different types of scale bars (simple, single division, alternating, stepped, and hollow).

Scale bars can also be formatted to meet the needs of the map’s audience and to improve their visual appeal. The scale bar’s distances can be measured in miles, yards, feet, kilometers, meters, and other units depending on the scale and audience.

To make the scale bar more practical and less overwhelming, the subdivision frequency and distance between subdivisions within the scale bar can also be changed.

The color of the scale bar or line can also be changed in order to lower the scale bar in the map’s visual hierarchy. When formatting your scale bar, keep your audience and scale in mind.

## How to Draw A Scale Bar

To draw the scale bar, you follow these steps

1. Add the scale bar layer after all your geographic layers.
2. Select the layer and double-click to go into edit mode.
3. Add a CartoCSS Class for your scale bar in the section Style > CartoCSS Classes > Layer Styles.
4. Under General Style set the style for drawing scale bars. For example, if you want a scale bar to be red, you can change the color in this section.
5. Check if any of the other options are needed for your map and select them in this section or add more options here as needed (you can see examples of some of these symbols below).
6. For the ‘Scale’ option and ‘Subdivisions’ set the distance between your subdivisions to what is called a “step value”.
7. For the ‘Color’ the color of the scale bar can be changed. To make the scale bar more appealing to your audience, you can change its color in this section.
8. For the ‘Size’ set the size of your scale bars to achieve an approximate visual hierarchy of your map.
9. Add or delete the ‘Scale type’. Add this type to be able to change the general style of your scale bar.
10. Add or delete the ‘Line series’, if you want this feature in your scale bar then select the ‘Line series’ option.
11. Check for any other options that can help you achieve what you want and select them in this section or add more options here as needed (you can see examples of some of these symbols below).
12. Click the OK button to finish adding, saving, and closing your map.

## Examples of Scale Bars

Here are some examples of scale bars and their uses:

### Global And National Scale Bars

If we are working with a map of all the countries on earth and the scale of each country is similar, then we can use a global scale bar.

This helps the users to know how big each country is from another. A map that has this kind of scale bar will give us an idea of where each country would be in relation to other countries.

### Local Scale Bars

If we are working with a map of an area and the scale of distance is very different in each location, then we can use local scale bars.

For example, if we want to work with a map that shows the height of different mountain peaks, or a map that shows how many kilometers there are between different locations, then this kind of scale bar will give us an idea how far away each specific location is from other locations.

### Roadmap Scale Bar

If we are working with a map that represents an area with major roads, giving each road a different color, then we can use a roadmap scale bar.

This kind of scale bar is very useful on maps which represent an area with major roads because it allows users to understand how many kilometers separate each different location and how much time it takes to get from one place to another.

### Matrix Scale Bar

Matrix scale bars allow the user to see how several values relate. Matrix scale bars are popular on choropleth maps.

For example, if we want to work with a map that shows different types of species in a given area and the number of species is different for each type, then this kind of scale bar will allow the users to see how many species there are for each type.

### Data Table Scale Bar

Data table scale bars create a spreadsheet-like visual effect.

For example, if we want to work with a map that shows the number of people who are employed in different industries to the right of the map and this information is shown in rows and columns on the left side of the map, then we can use data table scale bars.

This type of scale bar will make it easier for users to understand what industries there are more or fewer people employed in.

## Scale bars in different areas

These areas are:

### 1. Scale Bars in Science

Scientists taking pictures of phenomena on the cellular or similar minuscule levels rely on scaling their images appropriately to represent the size.

This could be helpful to, for example, communicate the relative size of cells in a population or neurons in a network of the nervous system. The ways to do this depend on the specific software used in imaging.

Other methods of defining a scale can be more straightforward with simple photography. Consider photographing a specimen or cell culture next to a ruler to make it easy for readers to determine length and size.

### 2. Scale Bars in Photoshop

Some later versions of Photoshop can make it simple and quick to add scale bars to microscope images.

You must first determine the pixel size of the camera used to generate the images, as well as whether or not binning was used in the image production. You should also determine the lens magnification and magnification for both C mount and objective magnification lenses.

Then, using the following formula, you can calculate the actual pixel size of the microscope images: Actual Pixel Size = (CCD Pixel x Binning) / Lens Mag x C mount x Objective Mag

### 3. Bars in ImageJ

There are two ways to add a scale bar in ImageJ. The first approach involves capturing a picture of the scale bar (such as a ruler or micrometer), using the straight-line selection tool, and drawing a line across the scale to determine a known distance.

Select the “Analyze” option, then “Set Scale” and enter the required distance in the provided boxes. Select “Global” to have it apply to all photos.

The second technique is to change the scale directly using the “Set Scale” menu choices without measuring. This strategy can be used if you know the scale of your imaging method.

After that, choose the photos to which you want to add a scale bar and select “Scale Bar” from the “Analyze/Tools” menu. This should result in a scale bar being added to your image. You may also adjust the scale bar’s size, color, and placement.

## FAQs

### What is Scale bars?

Scale bars are a graphical representation of a unit of measurement. They are used to indicate the size of features in an image or map. Scale bars can be placed in a variety of locations in an image, but are most commonly found in the lower right-hand corner.

Scale bars are often used in maps, diagrams, and illustrations to provide a unit of measurement for the reader.

The length of a scale bar is typically specified in the legend or caption and can be any unit of measurements, such as inches, centimeters, or miles.

### How do you read scales?

Different scales read differently. Some scales have numbers along the sides and top of the scale with values given for each side, while other scales have a single scale line with values given at tick marks.

Usually, you will start with the far-left side and read to the right or top, but occasionally you may need to start on the far right and read leftward. The important thing is to know what units are being used.

The units that you read from a linear scale are in your measuring system (metric or US customary).

The units of a map scale are in the map projection.

### Why is a scale bar important?

A scale bar is important because it will tell the user how they can interpret the scale on the map. For example, a state with an area of 10% will be displayed as a line going through 1% on the map.

A global-scale bar can be used to compare countries with each other, such as on housing maps. A local scale bar can be used to compare between areas within cities or towns.

### How do scale bars work?

The scale bar is a graphical indication that tells the user how much each point on the map represents in terms of distance.

### Is there a standard scale?

There are no standard scales, so the scale on any map will vary depending on the scale used to make it and who is using it. There are, however, scales that show many common things and they you can use to help understand how local areas relate to one another.

### When a scale bar is placed on a map, what are its main features?

A scale bar has two main features: its length and its orientation.  Length describes how far the line stretches from top to bottom.  Orientation gives information on which side of the line to read from.

### The goal is to get the line length equal to the actual length of the units.

For example, if you have a country that covers 20% of the land area in your data, then you would need a scale bar that is 20% as long as the country’s land area.

Orientation is just as important. You want to make sure that your scale bar reads from left to right (or vice versa), not from bottom to top.

### What is a scale bar on a drawing?

A scale bar is a linear graphic separated into equal segments that is used to measure distances on drawings and/or maps that are prepared to a certain scale but are not necessarily printed to that scale.

### What is an example of a bar scale?

The distance in the scale bar illustrates a connection between distance on a map and distance in real life. This scale bar’s units, for example, are in kilometers. Each tick graphically represents a kilometer, on which you may place your fingertips to estimate its approximate distance.

### Do all maps need a scale bar?

No. The scale bar is not required if the map includes all the necessary information for making a conversion.

### What does a scale bar look like?

A scale bar is a straight horizontal or vertical line with several tick marks (markers) separated into equal segments. The ticks should be evenly spaced and the distance between each tick mark should be noted.

The bottom of the scale bar should include a percentage or ratio that shows how much of the actual distance is represented on the map.

### What determines the look of a scale bar?

The type of map and the units being used determine the look of a scale bar.

### What is bar scale also known as?

Also known as a line scale, bar scale, or linear bar scale.

### Are there two scales on the same map?

No. The second scale is placed on top of the original map. If you are using a commonly relied upon standard such as the UTM or STMA, then your map and its accompanying coordinate system will always be prepared to that standard.

### What is the function of a scale bar in biology?

A scale bar with a handy unit of length is added to the image captured by the camera and becomes an essential component of that image.

If the image is then raised or decreased in size, the scale bar adjusts in proportion, allowing you to always see the proper size of the cells or tissue.

### How do I create a scale bar in Word?

To create a scale bar in Word, open the picture file, then right click and select “AutoScale Image.” Click on the “Set Scale” menu and enter the desired value. Click on “OK” to confirm.

NOTE: Using AutoScale Image will sometimes distort some of your images by cropping them. If you want to crop without affecting the scale bar, you can use Photoshop’s Crop tool and set the option to ‘Always Crop.