Abstract: For the wireless local area network based on WiFi in open-pit，data transmission time from mobile terminal to server reflects the network quality of the mobile terminal's location in a sense. Data transmission time of different points in whole open-pit is sampled，and then processed them with Kriging interpolation method. So the distribution of data transmission time in whole open-pit was obtained，and it is a digital expression of network quality. By making use of Voronoi diagram and MER (minimum enclosing rectangles) to index related spatial data of network quality，the data transmission time of the mobile terminal's location can be obtained，and this value can be an effective evidence for arranging the allocation of resources of mobile terminal program reasonably.

Key words: Kriging interpolation, Open-pit, Wireless local area networks, Spatial query