Explaining this in detail is beyond the scope of this FAQ, but if you missed Geography 101, check out this NASA page for a good explanation.

Check out the "Mapping and Geography" section on the links page - especially the MapBlast and MapQuest links.

There are a lot of speculative theories floating around. The following list includes a few of them.

Every point located on the equator (an imaginary great circle passing round the middle of the Earth) is at zero degrees of latitude. Zero degrees longitude is every point on the Greenwich Meridian or primary meridian - an imaginary line which runs from the North Pole to the South Pole. By international convention it runs through "the primary transit" instrument (main telescope) at the Royal Observatory in Greenwich. Check out the Royal Greenwich Observatory special visit.

Latitude and longitude may be obtained from the property deed or county plat maps available at the local library or county recorder. If the information cannot be obtained from the above sources, contact the DNR Emission Inventory Staff for assistance.

The downloadable ZCTA gazetteer files contain the latitude/longitude coordinates for each Census 2000 ZCTA. Coordinates for ZCTA internal points (calculated by considering the latitude/longitude of all bounding features and then creating an area-weighted average point inside the polygon) are also available in the TIGER/Line® Files.

The easiest way is to use the Virtual Globetrotting Geocoding Tools. With these tools, you can find a latitude/longitude from: IP address Additionally, you could use the techniques in submitting a map to find a location on the map.

Yes My World can convert data as long as you know what coordinate system the data is in. When you import the data, it will ask you.

Post your data in unprojected latitude/longitude using decimal degrees, with west and south directions shown as negative values. Latitude is the Y and longitude is the X. For example, 105 degrees 30 minutes west would be represented as -105.5 degrees. To convert from degree-minute-seconds (dms) units to decimal degrees (d.dd), use the formula:

It depends on where you got the data from. Lots of data that can be downloaded from the internet comes with metadata (data about data). You can usually find a section in the metadata describing the coordinate system that the data is stored in.

Individual values of latitude and longitude can be, and in most cases would continue to be, stored with particular data items (georeferenced objects).

Yes, it is possible, by overlaying an hCard with the location markup (see the brainstorming on hCard locations), e.g. using your lat long example (taking the values as given, someone feel free to fix these to be the real values). The code example(s) are presumed to be inside an element with a class name of "vevent". See the hcalendar-location-hcard-example page for details.

Q19. I digitize my map and set the display and calibration units as Lat/Long, but when I export my map the units are in meters! Q20. I am having a problem printing ("Out of global memory" error, only a portion of the map prints, etc.).

StarGPS-NX outputs the lat/long in degrees, minutes and seconds (rounding to the nearest second). If the telescope controller does not support seconds then it rounds to the nearest minute.

For most of my maps, you can use one of the following. For the Blacks and Prisons in California map, I don't have a way right now. Edit the URL in your browser by hand. Look for something like lat=-122&long=37 and change those latitude and longitude coordinates to the ones you want. Use the Google Map zoom tool on the upper left hand side to zoom out, move to where you are interested in, and zoom in again.