Latitude measures your geographic position on a north-south axis, specifying location using a three-part measurement made up of degrees, minutes and inches. The corresponding east-west measurement, latitude, uses the same pattern of coordinates. You can determine your own location mathematically based on GPS software and hardware as well as telephone number information. To figure out another person's latitude based on his phone and its number, look to basic online reference tools or software as your search tools.

Telephone Number Analysis

Reverse phone-number analysis capabilities abound on websites that also offer contact information when you type in the name of a person you're seeking. These sites can correlate a phone number's area code with part of a state or large metropolis. In most cases, the number's prefix -- its first three digits after the area code -- can specify its location more closely than the area code can. With the enormous numbers of mobile phones now in use, some phone prefixes resolve to specific service providers rather than to geographic areas, but numbers that began as landline connections still point to portions of a city or town. In some cases, reverse phone analysis sites provide you with an actual address for a telephone subscriber.

Translating Location to Coordinates

Once you know the geographic area in which a number originates, you can derive the latitude and longitude of that general location. Some websites accept various forms of location information -- city and state, names of famous buildings and places, or topographic features -- and return latitude and longitude coordinates. Other sites include or substitute a map on which you can click to locate the spot for which you want location information. These maps incorporate zoom features that show you smaller, more-specific parts of the United States to ease the task of making a selection.

Mobile Phone Location

You can use the optional smartphone apps that help you find a lost handset to locate a mobile phone you actually own. In addition to find-me software, app developers and social media sites also offer products you can install to share your geographic location with the people who make up your inner circle. These apps must be installed both on your phone and on the phone of another person you want to find. App preferences determine whether an individual agrees to share location data through these kinds of software. To identify your own latitude, simply check your phone's coordinates.

Other Considerations

Social media sites encourage location-based check-ins that tie where you are to when you're there. Making your geographic location public raises significant privacy concerns, especially if you use an app that shows your movements in real time. The same concerns apply when you're searching for specific location information about another person. Even if you want to find latitude information for a research project or to compile a family atlas, consider the consequences of investigating someone's whereabouts before you dive in to an all-out search.