Proximity statistics

What does the survey comprise?

Purpose

Provide insight into the travel distances to different facilities of persons for areas with inhabited addresses. Providing insight into the options available for a facility: the number of facilities within a certain distance for people at inhabited addresses in an area.

Target population

The distances are calculated for all persons at inhabited addresses.
The population numbers only include persons who are included in the municipal database of a Dutch municipality. In principle, everyone who lives in the Netherlands for an indefinite period of time is included in the population register of the municipality of residence.

Statistical unit

The average number of kilometres to a facility and for part of the facilities the average number of facilities within a certain distance.
Publications are made at the level of areas where personal data cannot be traced individually. The results are published at the level of the Netherlands, parts of the country, provinces, COROP areas, municipalities, districts and neighbourhoods.

Date/year survey started

2006.

Frequency

2-3 times per year.

Publication strategy

The data is final at the time of publication.

How is the survey conducted?

Survey type

The data is integrally observed and compiled by combining different sources.

Survey method

The distance from an inhabited address to the nearest visiting address of a facility is determined. This distance is calculated per address over paved (car) roads. This takes into account grade-separated intersections, ferries and one-way traffic on national and provincial roads. Routes crossing the Dutch borders are not included into the calculation.
All persons at the inhabited address are assigned a calculated distance to the nearest facility. The average distance per area to a facility is calculated by taking the average of the calculated distance for all persons living in that area. The nearest facility does not therefore have to be located within the same area.

The average number of facilities within a fixed distance per area is calculated by taking the average of the calculated numbers of facilities per person, for all people in that area. The more facilities available within the fixed distance, the more choice the residents of the area have for these facilities. The fixed distances are determined at 1, 3, 5, 10, 20 or 50 kilometres.

Depending on the density of facilities, the three most relevant distances are selected for publication in the table.

Respondents

To determine the addresses of persons: Municipal Personal Records Database (GBA).
Addresses and locations: the file Address Coordinates of the Netherlands (Kadaster).
The connections by road, formed by the network of paved roads and roads, are built based on the National Roads File (Rijkswaterstaat)
The address details of facilities are obtained from various (external) sources and institutions.

Sample size

n.a.

Checking and correction methods

An integral assignment of addresses of facilities and persons to locations on the map is checked. Invalid addresses of facilities are assigned a location with the help of information via the internet.

Weighting

n.a.

Quality of the results

Accuracy

A valid address location can be determined for 99.7 percent of the people. The remaining 0.3 percent of the persons is not taken into account in the analyses and outcomes.
The end results are published only when the exact location (x,y coordinate) of the address of 90 percent or more of the inhabitants in the area can be determined. In addition, the average is only published for at least 10 inhabitants per area.

Sequential comparability

The distances and densities of different years can’t always be used for a correct representation of the development over time. The boundaries or codes of the areas can change annually, so that addresses are provided with a different code. In general, this is a bigger problem for small areas such as districts and neighbourhoods than for larger areas such as municipalities.

Quality strategy

Throughout the process several checks are performed to ensure the quality of both the input and output of the distance calculations. Furthermore, checks are performed on internal consistency of the results and whether the results are complete.