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Acquiring Risk Map

This section describes the risk maps widely used by EvWH.

  • Risk Values

    When the rules obtained by association rule extration are applied to real data, certain values for certain times and places based on the rules are obtained. Since EvWH extracts rules to determine the ease with which traffic congestion can occur based on precipitation or the dispersalrate of air pollutants based on temperature and humidity, the obtained values are referred to as "Risk Values."

  • Risk Maps

    In the API to obtain vector data from risk maps (mapserv.riskmap) and the alert API, risk values distributed across time and space are expressed in a "Risk Map" format.

  • Risk Map Management

    Risk map entities are clusters of records made up of temporal attributes (start date and time and end date and time), spatial attributes (polygons) and risk values measured (or predicted) at that time and space.

    EvWH manages individual risk maps as single tables arranged under a riskmap schema.

Common specification for the riskmap data

Tables that manage risk maps must define the following four columns.

Column Name Data Type
start_datetime timestamp with time zone
end_datetime timestamp with time zone
geom geometry
risk integer

  • Make it unique with the set of start_datetime, end_datetime and geom

  • Create Btree multicolumn index on start_datetime, end_datetime, risk to achieve better performance

  • Created tables need to be browsed based on the theme name to be used through the Web API. The administrator controls relationships between the risk map tables and theme names.

API Key

An API key and private key are required to use this API. Please apply to the system administrator to obtain it It is necessary to send each with the following key name to the HTTP header part when sending an HTTP request

  • API Key: APIKey
  • Secret key: Secret

API List

  • mapserv.riskmap Riskmap distribution

    Obtains geometry data from the riskmap that intersects the specified spatio-temporal range as contor vector polygons, and returns it with the risk values in GeoJSON format.