Recording Longitudes and Latitudes

Genealogists have always been taught to record our sources of information. We not only record the name of the book or other source of genealogy information, but we also record the location of the building (repository) where we found it. Typically we record the building's name, street address, city and state.

With today's technology, shouldn't we also be recording the geographic coordinates? With GPS receivers and the plethora of high-quality on-line maps, it is now easy to find the exact latitude and longitude of any address. Unlike street names, the longitude and latitude will never change.

I have written about finding cemeteries and other locations of genealogical interest by using GPS receivers. Shouldn't we be recording the exact latitude and longitudes of those cemeteries into our genealogy databases? Perhaps the cemetery's location alone isn't enough. Should we record the exact location of the ancestor's tombstone.

How about the location of great-great-grandfather's farm? I believe the latitude and longitude of that farm would be a valuable entry in your database so that future genealogists who have access to your data can find that farm's location, even if it has since become covered with weeds or perhaps become a high-rise apartment building. In short, I think we should record the geographic coordinates of every location in our genealogy databases.

You can enter the latitude and longitude of any location as a text note into most any modern genealogy program. However, several of the better genealogy programs have specific database fields for these coordinates.

If you own a GPS receiver, the next time you visit an ancestral site of any sort, you should record its geographic coordinates into your database. You can also find similar information by consulting topographic maps.

Comments

[theKiwi]

Google maps is a great help with this too, and here's an example of it in use in an online genealogy software - TNG - The Next Generation of Genealogy Sitebuildling..

http://roger.lisaandroger.com/getperson.php?personID=I16&tree=Roger

Happy New Year

Roger

[Yvette Hoitink]

I totally agree with you about the importance of geographic locations. In the region where my ancestors come from (the eastern part of the Netherlands), people are named after the farm they lived on. I love taking pictures of the farms that people I'm researching owe their names too. In the past, I've had problems figuring out which farm was which when I got back at home.

But now I have a new toy: a Nokia N95 telephone that comes with a camera and GPS receiver. This allows me to take pictures that are automatically geotagged, making it easy to identify the farms I photographed.

[Paula Kelley Ward]

I've been told that GPS is only accurate to within 50 feet. I don't have a GPS receiver, so I don't know if this is true or not. From the gist of the above discussions, it sounds as if you actually can identify the exact coordinates of, say, four tombstones in a cemetery. Can anyone verify this?

I did a Google search for "GPS accuracy," and this Wikipedia article (see below) covers a lot of information about accuracy. Apparently military GPS receivers are more accurate than civilian GPS receivers.
http://en.wikipedia.org/wiki/GPS#Accuracy_and_error_sources

I'd love to hear (read) a discussion about this.

[Dick Eastman]

GPS accuracy varies depending upon several factors. The primary consideration is how many satellites are within range at that moment. The more satellites, the greater the accuracy.

Generally speaking, a GPS receiver is always accurate plus or minus 50 feet and often can determine distances plus or minus ten feet or so when coverage is optimum.

Military GPS systems use a slightly different system that is not available to civilians and can almost always determine locations within a foot or two.

I have been told that accuracy is less in the polar regions. I haven't spent much time in polar regions in the past 30 years or so and haven't verified that myself.

- Dick Eastman

[Cedric Wyndham]

Does anyone know an automated method of pasting co-ords into a database?
I have about 1700 localities in my database. Nearly all exist in World Place Advisor v1.2, & in these cases the name in my database corresponds with WPA. I could just manually copy the co-ords into my RootsMagic v3 database, but that will take a lot of time & with my typing skills a lot of errors would result. I could copy the relevant RM table into a spreadsheet, if I could also get WPA's table (or another table of co-ords & place names) I could run a v-lookup function to paste the values, then paste the table back into RM.
Any suggestions?

[Andrew Millard]

If you are recording latitude and longitude with GPS beware that there are several different systems for latitude and longitude. Basically they differ in the geometric approximations they use for the shape of the earth. GPS uses a system known as WGS84, which differs from that used for British Ordnance Survey maps (OSGB36) and that in use in western Europe (ED50), so that the same lat/long reference in the different systems may refer to places up to 120 metres apart (see http://en.wikipedia.org/wiki/OSGB36 ). 19th century maps use a whole variety of systems, which may differ even more. Mostly being 100m out won't matter for a genealogist, but in a densely built-up area it could be a real pain if you are there with a GPS receiver trying to locate a specific building. So don't assume that a precise location from a map translates into precise lat/long for GPS or vice versa. Google maps uses a version of WGS84 which probably doesn't differ significantly from that used in GPS (see http://cfis.savagexi.com/articles/2006/05/03/google-maps-deconstructed for a somewhat technical discussion).

[Jim Agnew]

Building on what Andrew Millard wrote, the WGS84 "system" is referred to as a Datum. There are several datums in use. In North America, you can probably set your handheld GPS unit to read out in any of them (usually from the set-up screen), so be sure you are using the latest ones (WGS84 or NAD83 are the newest for North America, and are essentially equivalent) and make note of which datum you used when recording your latitude & longitude numbers. Older topographic maps from the U.S. Geological Survey used the NAD27 datum (North American Datum of 1927), which is quite a bit different from the current NAD83 datum, especially in longitude (east-west corrdinate). Longitude can vary by up to 100 meters (328 ft) between the NAD27 and NAD83 datums, making it difficult to locate a point on a map if the datum is not given. Several computer programs can translate Lat & Lon numbers from one datum to another - I use TOPO! from National Geographic, which is a compilation of U.S.G.S. topographic map sheets on CD-ROM. Buying a handheld GPS unit with "WAAS" also helps increase the accuracy of the location.

[Fred Nauman]

In August of 2006 my wife and I took a vacation trip to Nova Scotia. I had just recieved a GPS unit and installed it in the rental car at the airport. One of the reasons for the trip was to locate and photograph a monument to Pierre Thibaudeau, an ancestor of my daughter-in-law, which we knew to be located somwhere in Port Royal, Acadia.
Much to our surprise, an Annapolis County brochure listed the monument and included its GPS location. Although none of the locals we asked, not even the proprietor of the general store not more than 300 yards from the site, was aware of its existence, our new electronic friend took us directly to it.

[Judith Reesor Hutchinson]

My oldest son spent 21 years in the US Coast Guard, and has been to Antarctica and to the Arctic Ocean several times on ice breakers. On September 6, 2001, he was on the USCGC Healy at 90 degrees north (North Pole). He emailed me at that time that everyone's personal GPS receivers (including his) went wild with all sorts of error readouts when they could not record Longitude. However, the ship's GPS (or whatever means they used to determine their location) worked fine.

[Sharon Zingery]

Can I read my coordinates on most of the GPS units now advertised? I was concerned that they might not tell me where I am, only how to get to where I want to be??

[Jason Presley]

Don't confuse a typical GPS receiver (which tells you your current coordinates) with a navigation system (TomTom, Garmin Nuvi, etc) like those you find in rental and higher end cars (which are just designed to give you directions).

[Jo Dye]

Have any of you become involved with the Waymarking movement, using GPS coordinates to locate sites, including many of genealogical interest? I'm actually wondering if anyone has experience with the site. Is it reliable and/or worth contributing to it? Thanks and Happy New Year to all! Jo

[Michelle Woodham]

Here is a link to a site where you can convert your GPS coordinates to various formats...

GPS Coordinate Converter, Maps and Info

http://boulter.com/gps/

I have found that my Garmin Etrex records postions in a format that needs to be converted for use with Google Maps on FindaGrave.com which are recorded in Decimal Degrees (WGS84).

[Tim Skinner]

Although a number of the better Family Tree programs support the storing of Latitudes and Longitudes (Legacy and Rootsmagic spring to mind) the trouble is that there is no defined standard for saving this information in a GEDCOM file. Both the two aforementioned programs use "Custom Tags" in the GEDCOM files to store this info but both programs do it differently and so the data is not interchangeable.

The proposed draft standard for GEDCOM 5.5.1 defines a way this should be done but since the standard has never been released no vendors have adopted this method.

I've written a program "Map My Ancestors" for Geocoding GEDCOM files for use with KML/KMZ compatible programs such as Google Maps, Google Earth, Microsoft Earth etc. It will read the custom tags from Legacy and Rootsmagic if they are present but maintains its own Place name -> Latitude/Longitude mapping (so you could switch between different Family Tree programs if you wished without losing the Latitude/Longitude information.

I've included a tutorial video on my web site at -
http://www.familytreeassistant.com

Tim

[Tim]

I've recently updated Map My Ancestors to include a facility to export to most of the major Sat Nav and GPS systems as Point Of Interest (POI) files.

A free trial can be downloaded from -

http://www.familytreeassistant.com

Tim