A method for generating warning polygons for weather events in a geographic region , the method comprising: receiving (S101) measurement data from one or more sensors associated with the geographic region , the measurement data comprising sensor data related to a weather event and location data indicative of at least one location at which the sensor data was obtained; identifying the at least one location from the location data; identifying (S103) at least one map tile (C, E, G, K, L, O, R, T) of a map tile database that is within a predetermined distance to the at least one location , the map tile database configured to store partitions of map data according to an index of a plurality of map tile identifiers (A-T); calculating (S105), by a processor , a confidence level for the at least one map tile (C, E, G, K, L, O, R, T), the confidence level being inversely proportional to a distance from the at least one location at which the sensor data was obtained and a time that has elapsed since the sensor data was obtained; comparing (S107), by the processor , the confidence level for the at least one map tile (C, E, G, K, L, O, R, T) to a threshold confidence level; applying (S109) a DB-SCAN clustering technique to map tiles (C, E, K, O, R, T) with confidence levels exceeding the threshold confidence level, the DB-SCAN clustering technique grouping together map tiles (E, K, O, R) that are near one another and omitting map tiles (C, T) that have fewer neighbours to form a map tile cluster; and calculating (Sill), by the processor, a polygon by connecting a single corresponding point within each map tile (E, K, O, R) of the map tile cluster, wherein the polygon intersects the geographic region . receiving (S101) measurement data from one or more sensors associated with the geographic region , the measurement data comprising sensor data related to a weather event and location data indicative of at least one location at which the sensor data was obtained; identifying the at least one location from the location data; identifying (S103) at least one map tile (C, E, G, K, L, O, R, T) of a map tile database that is within a predetermined distance to the at least one location , the map tile database configured to store partitions of map data according to an index of a plurality of map tile identifiers (A-T); calculating (S105), by a processor , a confidence level for the at least one map tile (C, E, G, K, L, O, R, T), the confidence level being inversely proportional to a distance from the at least one location at which the sensor data was obtained and a time that has elapsed since the sensor data was obtained; comparing (S107), by the processor , the confidence level for the at least one map tile (C, E, G, K, L, O, R, T) to a threshold confidence level; applying (S109) a DB-SCAN clustering technique to map tiles (C, E, K, O, R, T) with confidence levels exceeding the threshold confidence level, the DB-SCAN clustering technique grouping together map tiles (E, K, O, R) that are near one another and omitting map tiles (C, T) that have fewer neighbours to form a map tile cluster; and calculating (Sill), by the processor, a polygon by connecting a single corresponding point within each map tile (E, K, O, R) of the map tile cluster, wherein the polygon intersects the geographic region . <EOS>