Resumen
Nowadays, the fingerprint scanner widely used to records attendance. However, this technology has a weakness. Much research has done to improve the attendance system by utilizing mobile technology, like usage a fingerprint smartphone and location by GPS sensor to validate user location manually. In this research, we developed an application to enhance the records attendance system with a smartphone by crossing numbers to verify user position automatically, which implemented in a mobile app. This application using the PNPOLY method for detecting the location of the user inside of the polygon area predetermined. This method is part of the crossing number algorithm for increasing x and fixed y from point P, which x is latitude, and y is a longitude. The result of the experiment demonstrated that the percentage of successful validate user coordinate inside edges of the polygon boundary is 87%, depending on the GPS sensor embedded into a mobile device.