In previous posts we spoke (Aoristic clock, Ring map and Grid by point density) about a series of geoprocesses related to criminology made together with Jaume I University (UJI). These geoprocesses can be used in different sectors, not exclusively related to criminology.

Now we are going to show the Aorist Clock by grid geoprocess. The main objective of this geoprocess is to visualize the distribution of the temporal component in a graphical way. Its distribution within the hours of the same day, and within the day of the week will be shown.

Temporal distribution of 150.000 crimes in New York

A square grid will be generated in which the same number of entities on which the analysis has been made will be placed, with the only difference that the geometry has been changed to a point type geometry that will be placed on the grid. The position of this geometry will correspond to the time field, according to the day and the hour in which the event occurred.

When having all the starting elements with all their fields, we will be able to apply other type of symbologies. By default, a dot density symbology will be generated (as seen in the first image), but we could apply any other. A legend by categories or a label could be applied too. Other legends could also be applied, such as grouping points.

Temporal distribution analysis of 16 features by categories.

The geoprocess parameters are a layer that has two fields with time and day (which could be contained in the same field), an optional filter of the input data, and two proportion parameters that will help us to manage the horizontal and vertical size in case you want to modify it.

This geoprocess can be tested with the next Release Candidate version of gvSIG Desktop. You can download it from Tools -> Add-ons manager and search the “Geoprocess: Aoristic clock” geoprocess. Once installed, and after restarting gvSIG, it will appear at the “Scripting – Data Analysis – Aorist Clock” section.

If you have any doubt or you find any error you can send us the information through the mailing lists.