Imprecise area search
The imprecise vicinity search is a vicinity search in which regional distances from postcodes are determined without using a postcode database.
Sensibility and disadvantages
Inaccurate area searches are only useful if you want to give a rough overview of the regional affiliation of postcodes. Distance calculations are generally not possible with this method; this method is also very error-prone and should only be used if no geographic database enables a search for the vicinity.
Imprecise area search in Germany
In Germany, numeric postcodes with five digits are used. This makes it possible to identify nearby places within a limited framework. The identification is problematic among other things in federal state border areas , since there are big leaps in the number ranges. An assignment of postcodes to federal states is not possible without a corresponding database.
An example: The postal code 63067 belongs to Offenbach am Main . The first two digits indicate the regional allocation; the answer to the question "Which places are near Offenbach am Main?" is therefore partially possible.
Partly recursive
Since in practice a proximity search is used to find locations (e.g. branch search), a partially recursive algorithm has become established. The user enters an n-digit postcode with which a first search query is started. If no results are found, a new search with n − 1 digits is started. This continues until either there is no longer any position or one or more results have been found (e.g. 63067 → 6306 → 630 → 63 → 6).
Other countries
In some other countries such as Austria, Switzerland, Australia, Belgium, Denmark, Portugal, Sweden and Spain, an imprecise area search similar to that in Germany can be implemented.
In other countries, imprecise area searches are not always feasible or there is no information about their postcode systems.