An Analysis of the Street Names in Four U.K. Cities

This article presents the results of an analysis of the 17,327 street names in four U.K. cities: Cambridge, Cardiff, Edinburgh and Oxford. These results can inform the implementers of indexing and filtering algorithms for applications that require the input of street names with the keyboard or by selection with the mouse from a list.

1. Introduction

This article presents the results of an analysis of the 17,327 street names in four U.K. cities: Cambridge (1598 streets), Cardiff (5351 streets), Edinburgh (5690 streets) and Oxford (1535 streets). These results can inform the implementers of indexing and filtering algorithms for applications that require the input of street names with the keyboard or by selection with the mouse from a list.

2. The Results

The following information was compiled for each city:

  • the shortest, average and longest street name length;
  • the number of occurrences of each street name length;
  • the number of street names starting with each letter of the alphabet.

The following table lists the shortest, average and longest street name length in each of the four cities.

Street Name Length
Shortest Average Longest
Cambridge 4 11 24
Cardiff 5 10 28
Edinburgh 5 12 30
Oxford 6 11 28

The following graph shows the number of occurrences of each street name length.

The number of occurrences of each street name length

Graph (a) below shows the number of street names beginning with each letter of the alphabet. This graph highlights that the most popular initial letters are C, H, L, M, P, S and W. Graph (b) shows the number of street names beginning with each letter of the alphabet averaged over each city, plotted against the most frequently occurring letters in English. The initial letter of the street names do not follow the frequency distribution of the letters in English; C is the most frequent initial street name letter rather than E, the most frequent letter in English. Implementations of indexing and filtering algorithms should ensure fast access to the most popular initial letters of the street names.

(a)
The number of street names beginning with each letter of the alphabet
(b)
The number of street names beginning with each letter of the alphabet averaged over each city, plotted against the most frequently occurring letters in English

Selecting a street name from a long list is eased if the number of names in the list can be reduced to a more manageable number, say 10 or 20 names, with a list filtering algorithm. One such filtering algorithm removes the items in a list that do not begin with the characters entered into a text input box. Using this algorithm, I analyzed the street names of the four cities to discover how many letters of a street name need to be entered to reduce the number of street names in a list to 10, 20 and 50 street names. Tables (a), (b) and (c) below show the minimum, average, and maximum number of letters of a street name that need to be entered to reduce a list of street names to 10, 20 and 50 names, respectively.

(a)
Minimum Average Maximum
Cambridge 1 4 13
Cardiff 1 3 9
Edinburgh 1 5 16
Oxford 2 2 8
(b)
Minimum Average Maximum
Cambridge 1 3 10
Cardiff 1 2 5
Edinburgh 1 3 16
Oxford 1 2 4
(c)
Minimum Average Maximum
Cambridge 1 3 7
Cardiff 1 1 3
Edinburgh 1 2 6
Oxford 1 1 3

For each of the cities, the smallest number of letters that need to be entered to reduce the list to 10, 20 and 50 street names is 1. Graph (a) above shows that street names starting with Q, U, X, and Z are uncommon; entering Q, U, X or Z as the initial letter of a street name immediately reduces the list of street names to 10, 20 and 50 street names. The average number of letters needed to reduce the list to 20 names is either 2 or 3 letters depending on the city. The average number of letters required to reduce the list still further to 10 street names is between 2 and 5. A list size of 20 street names is a manageable number from which to chose one name; it is not worth entering the extra characters needed to reduce the list to 10 names.