METRIC (MEsure des TRajets Inter-Communes / Carreaux // Measurement of Inter-municipal / Grid Travel) is a tool, designed internally by INSEE, for calculating travel distances and times from one municipality to another (in the case of supra-municipal data), as well as from one point to another (X, Y) (in the case of geolocation data).
When data are available at the municipal level, this module can be used to calculate the theoretical travel distances and times from the main town of one municipality (the starting point) to the main town of another municipality (the destination). In particular, for all travel occurring within a given municipality, METRIC will set, by convention, the time and distance at zero. The average times and distances calculated for a given set of municipalities will thus be greatly underestimated. Consequently, there is a non-negligible bias for issues related to access to (public) facilities and commutes between home and work, which are scenarios that jointly represent a large proportion of travel made within a given municipality. This is why, when no geolocation data are available, a user will be prompted to use a municipal database for which, for each municipality, the average travel distance and time within a municipality have been estimated by INSEE.
When a user has geolocation data (X, Y coordinates), METRIC will calculate the travel distance and time between pairs of points (which are either located in the same municipality or in different municipalities of the same department). Unlike the supra-municipal module, travel within the same municipality will not have distance and time set to zero. This sub-municipal module can also be used to calculate theoretical travel distances and times to various (public) facilities: for every 200-metre square of a selected municipality, the time and distance to access the nearest facility are provided (NOTE: the calculated distance and time are theoretical because they do not indicate whether a given facility was actually accessed).
METRIC has been built using cartographic holdings made available by the IGN (Institut Géographique National //National Institute of Geographic and Forest Information). These holdings provide information on the different types of existing roads (motorway, quasi-motorway, single carriageway road, etc.), as well as their respective length, gradient and sinuosity. This information has then been cross-referenced with population data (at 1 km) to determine the population density of each of the zones.
The application was developed using R and uses, among other things, the igraph package (a set of functions for creating and manipulating graphs). In cases where there is no possible route between two municipalities or two points, the application returns the value of 9999.
Accessing and using METRIC
METRIC is available as an application , and is accompanied by:
- a user guide (available in French only) and
- a municipal database with estimated distances and times for trips occurring within the same municipality, accompanied by a note detailing the allocation method used.
To use METRIC for performing your own travel distance and time calculations, please submit a formal request via the Quetelet-Progedo-Diffusion Data Request Platform (reference APF-0004) APF-0004).
For more information, please consult the METRIC User Guide (available in French only).