A software application installed on a mobile device periodically measures a parameter and records it along with the position associated with the measurement. These data are recorded on the device's internal memory and displayed in the form of a map so that users can navigate to locations with desired parameter levels. In one embodiment, this parameter may be cellular signal strength, allowing users in areas with no useable cellular signal to find a location where a phone call can be placed. Parameter and location data may be displayed in a map as they are acquired or in other embodiments they may be preloaded onto the device, for example allowing cellular signal strength maps to be displayed on a device even when it has no current data connection.