Introducing 3D representations as an advanced method for the case of the Hot-Warm-Cold zone model

Abstract

The use and availability of 3D data and 3D applications is increasing every year. In this light, the Dutch National Police is trying to implement more 3D data for several cases. One of these cases is the Hot-Warm-Cold zone model, a safety model in which the 3 different zones represent differences in safety during calamities. Currently 2D data is used in this case, but the use of 3D data can increase safety, effectivity and efficiency. In this research a method has been created for the introduction of 3D representations for incidents requiring the Hot-Warm-Cold zone model.

A distinction has been made between 2 different kinds of incidents. ‘Ad hoc’ incidents concern incidents which happen quite unexpectedly and at locations not known by the police, while ‘high risk’ incidents happen at locations known by the police and thus are already observed and analysed prior to any incidents occurring. For the ‘ad hoc’ incidents a 3D representation has been developed in ArcGIS Pro, using a 3D city model and various visibility analysis and buffer tools. A 3D representation for ‘high risk’ incidents on the contrary, has been developed with 2D data in ArcGIS Pro as the foundation, while the more detailed 3D representation has been created in CloudCompare using a Hidden Points Removal algorithm on point clouds.

For the ‘ad hoc’ incidents as well as the ‘high risk’ incidents 2 different forms of 3D representations have been developed. The nature of the incident can differ, thus depending on the incident being related to explosions, chemical substances or violence, the shapes of the hot, warm and cold zone of the 3D representation differs. For chemical incidents the factor of the wind is of such significant importance that it needs to be included in the 3D representations. For these specific incidents an ovoid 3D representation is developed, as the wind can be depicted through this ovoid shape. Other incidents, for instance related to explosions and violence, are not influenced by the wind and therefore a sphered 3D representation is adequate where the hot, warm and cold zone are depicted through spheres.

Depending on the type of incident, a suitable 3D representation can be used within the operative police environment. These 3D representations make it easier to decide on the outlines of the hot, warm and cold zone and additionally ensure that more accurate and precise outlines can be created. This establishes a safer environment of the incident location as more information on the location is available. Besides, the information which is available is more understandable as the 3D representations stand closer to the real-life situation.