Latitude and Longitude in Family History Research
Analyzing family/pedigree relationships using geographic criteria
Among relatively stable populations before the Industrial Revolution the significant events of people's lives such as birth/christening, marriage and death/burial tended to occur in small geographic localities.
People of the past were like people of the present. They moved infrequently, or not at all, unless compelled to do so. Movement was dictated by topography, political system, socioeconomic status, economic opportunity, and other considerations. Travel was difficult and costly. People frequently followed the easiest course and moved the shortest possible distance when purchasing property, establishing their trades and families, etc. For these reasons, locality is always an important consideration in family history research, especially before the Industrial Revolution.
How do we know which localities were close to each other? What does "in the vicinity" mean in terms of family history research?
We can determine goegraphic proximity by consulting maps, atlases, gazetteers and other tools. We can also compile latitudes and longitudes for places where the events occurred, such as churches, and then calculate the distances between selected points.
In terms of family history research, the shorter the distance between two life events, the more likely they are to be related. The more widely separated two life events, the less likely they are to be related.
Failure to read primary sources, and to utilize maps, atlases, geographic and historical tools, are extremely serious omissions which invariably result in significant pedigree errors.
What follows is a brief article for non-mathematicians who wish to learn how to use geographic coordinates to enhance the quality of their research. The article uses photographs, illustrations and simple instructions to give non-mathematicians a basic understanding of latitude, longitude and distance computations as applied to family research. It is not intended to be historically, geographically nor mathematically comprehensive.
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