Which of the following map ratios would be used to show a very small area of a neighborhood?

Maps are a graphical representation of the world or a section of the world.  

As a representation of the world, maps are compressed versions of the real world meaning that a large piece of land is recreated onto a smaller piece of paper or digital file.  

Maps are representations of some geographic features in the world. Map: International Hydrological Studies Map, USGS, public domain.

The relationship between the real world size of a geographic feature and its representative feature on a map is known as scale.

Scale is often represented as a ratio between the real world size and the size in units on the map.

How Scale is Shown on a Map

There are three main ways that scale is indicated on a map: graphic (or bar), verbal, and representative fraction (RF).

Bar Scales

Bar scales show scale using a graphic format.  The actual length of the bar scale shows what that length represents in real world units.

 In the example below, the bar scale shows the distance on the map that represents ten kilometers or a little under six miles.

Showing scale using a graphic scale.

Scale can also be represented verbally or in text format. 

Verbal Scale

For example the verbal scale, 1″ = 100′ means that one inch measured the map represented 100 feet on the ground.  

This map prepared by the US Census Bureau of the state of Oklahoma includes a verbal map scale.

Base map of the state of Oklahoma prepared by United States. Bureau of the Census. Geography Division. Library of Congress, public domain.

This decorative verbal map scale can be found on a map of the city of Washington from 1796.

Map scale. From: Map of part of the city of Washington shewing the situation of the mansion house, grave yard & buildings belonging to Mr. Notley Young : original proprietor of that part of the city, 1796. Library of Congress.

Representative Fraction

This type of scale representation visually looks very similar to representative fraction (RF).  However, representative fraction avoids the use of units in detailing the scale of a map.  

For example, scale that has a RF of 1:100 means that every one unit on the map equals one hundred of the same units on the ground.  

In comparable terms a RF scale of 1:1,200 is the same scale as a verbal scale of 1″ = 100′.

A set of map scales from a USGS 7.5 minute Topo map showing representative fraction (RF) and three different bar scales for different metric and standard units.

Large Scale and Small Scale Maps

Maps can be described by how varied the scale is.  

Maps that show a large geographic area in comparison to the relative size of the map are known as small scale maps.  The small scale refers to how small the fraction is.  

Mount Rainier in Washington shown on different scaled USGS topo maps. Source: USGS, public domain.

A map showing the entire world would be considered a small scale map whereas a map showing a neighborhood would be considered a large scale map.

Small scale maps tend to show a larger geographic area and less detailed and large scale maps show a smaller geographic area with greater detail.  

In the example below, the small scale map of the Chicago area shows only major transportation routes, and rivers.  In the large scale map, far more detail is available such as all the streets, building footprints, street flow direction, and increased labeling of more features.

Small scale map showing Chicago (upper map) and a large scale map showing a neighborhood in Chicago (lower map).

Watch: Understanding Map Scale

Related resources

• Understanding scale in GIS
• What is a map?

What is the definition of scale? Scale is the relationship that the depicted feature on map has to its actual size in the real word (more: map scale).  

All maps are modeled representations of the real world and therefore the features are reduced in size when mapped.  

In other words, scale is the measurement of the amount of reduction a mapped feature has to its actual counterpart on the ground.

Representing Scale on a Map

All maps will have an indicator of the scale of the map.  

A map that doesn’t conform to a specific scale will be indicated by the words “not to scale” (or NTS).  This notations is most commonly found on graphic style maps such as the  “we are here” or “how to get here” style maps used on invitations.  

Since GIS relies on a minimum threshold of accuracy and precision, almost all GIS-based maps will have a scale.

What are the Three Ways to Show Scale on a Map?

There are three ways to show the scale of a map: graphic (or bar), verbal, and representative fraction.  

Graphic Map Scale

Graphic scales, also know as bar scales, as indicated by the name, show the scale graphically.

Bar scale showing graphically the ratio of map units to ground units. The top scale shows the comparable ground measurement in kilometers (km) and the bottom bar scale shows the comparable length in miles.

Verbal Scale on a Map

A verbal scale is text based, with the scale shown as a number and type of unit measurement equal to a specified unit measurement on the ground.  The left side of the verbal is the unit of measurement on the map and the right side of the ratio is the unit measurement on the ground.  

For example the verbal scale, 1″ = 100′ means that one inch measured the the map represented 100 feet on the ground.  This type of scale is sometimes confused with Representative Fraction scales.

Representative Fraction as a Scale on a Map

Like verbal scale, representative fraction (RF) scale is also a text based scale but no units are shown.  

For RF, scale is a simple ratio of map to ground measurement with a colon between the two measurements .  

For example, a RF scale of 1 : 1,200 means that every one unit on the map is equal to 1,200 units on the ground.  There is no notation of the actual unit type used on a RF scale.  

Therefore a RF scale of 1:1,200 is the same scale as a verbal scale of 1″ = 100′.

Large versus Small Scale Maps

Maps are described as either large scale or small scale.  

Large scale maps show a smaller amount of area with a greater amount of detail.  The geographic extent shown on a large scale map is small.  

A large scaled map expressed as a representative scale would have a smaller number to the right of the ratio.  For example, a large scale map could have a RF scale of 1 : 1,000.  Large scale maps are typically used to show neighborhoods, a localize area, small towns, etc.

Small scale maps show a larger geographic area with few details on them.  The RF scale of a small scale map would have a much larger number to the right of the colon such as 1 : 1,000,000.  Small scale maps are used to show the extent of an entire country, region, or continent.

How Scale Affects Feature Representation

The larger the scale of the map, the better the features that can be detailed.

A map that shows the water network of a small area may show the river as a polygon layer and will show the tributaries of that river.  A small scale map covering the area would show that same river as a line feature and the tributaries would be removed (a process known as generalization).  

The smaller the scale of the map, the less the actual detail of a feature is preserved.  Smaller scale maps have river features that have the lines smoothed out whereas a large scale map would show more detail about the twists and turns of that same river.

Why Generalization is Related to Map Scale

So why not show the same level of detail regardless of the map scale?  There are two main reasons.  

The first reason is the noise level.  Showing a lot of detail for features on a small scale map would cause a lot of confusion on the map.  

By reducing the amount of detail to show only the most important aspects of a feature, the map shows a clearer picture of the area.  

The second reason is the file size.  

Features that have a lot of detail are larger in file size.  For a small scale map, loading several large layers will slow down the map production.

An Example of Small Scale Versus Large Scale Representation

Marina del Rey is an area of Los Angeles County that has one of the largest man-made small boat harbors in the United States.

The representation of this harbor on maps of the area is dependent on the scale of the layer used.  

The layer showing the counties for the entire United States shown in the image below has a very generalized coast line for this area.  The is almost no detail in the coastline and the harbor is not represented at all.

Marina del Rey area on a small scale map. The harbor is not shown at all on the map.

The map below shows the same coastline with a layer of all counties for the state of California.  While still a small scale layer, the coastline shows more detail.  The Marina del Rey harbor is represented by a small inlet on the map.

Marina del Rey area on a county map of the state of California.

In a large scale layer created to show just the County of Los Angeles boundary, the coastline for this area contains the highest level of detail, and a recognizable harbor is represented.

Marina del Rey at the county level.

The examples of how the detail of a coastline changes depending on the scale of the layer helps to illustrate as well the importance of carefully considering the scale of any data used for mapping and spatial analysis.  

Small scale data inherently is less accurate and less detailed than large scale data.  

Using small scale data for large scale analysis can lead to gross errors.  Data created for small scale purposes should not be used in large scale maps.  

Large scale data unless generalized, should not be used in small scale maps.

Watch: Large Scale Versus Small Scale Maps

Related Resources

What’s in a Map? – Understand the basic elements that make up a well formed map.

Cartographic Resources – Resources for learning more about cartography and cartographic techniques.