Back in 2011 when I started working with the Bührer dataset it was clear to me that all the emigrated Bührers are “family”, i.e. are more or less closely related to me. A first glimpse at the map’s family tree in 2015 showed that this assumption is somewhat shaky – most of the emigrated Bührers are rather distant relatives.
A renewed look (see above) gives a more precise picture: relative to me (generation and degree of relationship = 0) the closest emigrated relative is Michael Bührer (generation = 5, degree of relationship = 6) who directly descends from the 10th generation of my direct line of ancestors. The degree of relationship of US persons (living or dead) ranges from 6th to 11th degree. Not that related after all…
Note that indicated degree of relationship according to my calculation (I didn’t find an authoritative source on how to calculate it) doesn’t increase in direct descendancy unless the generation is below 0.
The original dataset from 2011 featured 4557 relevant persons (Bührers, spouses and their children/grandchildren). Up to 2017 the dataset had grown up to 9223 relevant persons, i.e. neatly doubled! This provided ample reasons to redo – with a couple of substantial improvements – the original mapping exercise.
The maps shows – as the earlier ones – the Bührers’ emigration to the United States (Map 1) up to the 1880s and subsequent internal migration up to now (Map 2).
A legend explains the symbology and the groups of emigrated Bührers with common ancestors. In contrast to the earlier maps there has been no manual tweaking, with exception of the orientation of the immigration arrows. The big challenge is clearly visible in Map 2: the larger number of persons means there’s really too much going on to fit it on one map!
The major changes compared to the earlier version in 2015 are:
Emigrated Bührers where matched against emigration/immigration evidence, e.g. passport lists, ships lists at port of embarkation, US immigration records and US census information. This allowed (see 2nd page of legend for emigrated groups of Swiss Bührers) to more accurately determine/narrow down the actual time of emigration.
Normalization, completion and geocoding of places was done using a person’s context (e.g. where other relatives had lived/died) to geocode places that otherwise would not be clearly identifiable (e.g. “West Rome Cemetery”). This allowed to geocode substantially more places and hence produces more migrations.
Determination of a common male ancestor was combined with deriving the family status for emigrants in a more robust procedure that can accurately handle also more complex cases such as three generations of emigrated Bührers with intermarriage with other emigrated Bührers. As a result some of the groups of emigrated Bührers have changed.
Assignment of persons to a time period (generations prior/beyond 1880) was reworked. This allows a flexible ad-hoc definition of periods based on the common minimal birth year of a group of siblings and their spouses. Furthermore extrapolation to ancestors/descendants via a generation offset (25 years) allows the period estimation of persons with no known birth year.
In terms of map-making the are few notable optimizations:
The number of distinct Bührer persons per county and common ancestry is indicated with pie charts, allowing to visualize both the total number of Bührers and the repartition by ancestry. QGIS 2.18 strictly speaking still doesn’t support this feature (treating diagrams as labels that float on top), but using a workaround with two map layers in the composer (one below with the base map including the pie chart diagrams and remaining places, the other above with the migration arrows and all the labels) did the trick.
Descendants are no longer shown (i.e. their immigration, migration as well as number of persons per county) because they are irrelevant/arbitrary in the US emigration context.
Meaningful migration labels are now fully computed, even though a few could still profit from manual tweaking. A custom label rankingfor migration paths was developed to prevent label cluttering and lets the important labels prevail (e.g. those with first migration evidence). Place labels were optimized to only show first migration evidence (in red) if this occurred in the respective period.
The – with 13 A3 pages very wide – family tree (Family Tree of Emigrated Buehrers) shows all persons that emigrated to the United States including their ancestors as well as their immediate relatives. Persons are aligned horizontally by generation, with oldest generations on the top. Squares denote males, circles females and triangles marriages. Persons represented by black line symbols are shown on the map whereas those with grey line symbols are not. Otherwise symbology follows the one for the map, i.e. line styling indicates category and colours show common male ancestors.
Data for the family tree was prepared in the project’s PostgreSQL database stripping irrelevant persons and families. The family tree was drawn in yEd (http://www.yworks.com) in “Family Tree” mode and styled via Properties Mapper.
The production of the map showing theemigration of Bührers from Switzerland to the United States relied on the following, largely self-developed sequential steps:
Normalization, completion and geocoding of places used for family and persons events
Identification and categorization of in-scope persons, notably persons born as Bührer or name varieties such as Buehrer (“Named”), spouses (“Married”) and their children/grandchildren (“Descendant”) that have different family names
Constructing a sequence of geocoded events for a person’s life, also considering childbirth for women. In case geocoded events lacked dates a natural sequence was assumed, i.e. birth followed by marriage, childbirth, death and burial.
Determination of an emigration/residence status relative to Switzerland, the US or third countries. Of particular interest were those that emigrated to the US as well as confirmed or assumed US residents
Determination of a common male ancestor for all Bührers that emigrated or have lived in the US and the generation relative to him
Deriving a family status for emigrants, i.e. whether emigrants emigrated as single, with their spouse or family
Assignment of persons to a time period (generations prior/beyond 1880) based on known birth years, ensuring a consistent assignment of couples and siblings to the same period
Construction of migration pathsegments following the sequence of geocoded events
Aggregation of migration paths per county and time period, including aggregated indicators such as the category of in-scope person with Bührer prevailing and the minimal generation involved
In the second half of the 19th century many farmers emigrated from the rural communities of the Swiss canton of Schaffhausen, mainly due to a local agricultural crisis and better economic prospects elsewhere. There were emigration peaks around 1850, 1870 and in the 1880’s with a large majority of emigrants heading to the United States. From 1868 to 1890 an equivalent of more than 10% of the canton’s population had left, a large number for Swiss standards at the time.
Among the emigrants were many Bührers from the small hamlets of Bibern, Hofen, Opfertshofen as well as from Herblingen and Stetten in the Reiat region. Originally immigrated from southern Germany the Swiss Bührer at large remained constrained to that tiny corner of Switzerland, which greatly facilitates genealogical research.
The maps shows the Bührers’ emigration to the United States (Map 1) up to the 1880s and subsequent internal migration up to now (Map 2). Almost all of them initially immigrated to a small area in northwestern Ohio around the city of Archbold in Fulton County; some of them migrated further west to Kansas, Texas or the Pacific Northwest.
In order to provide the necessary historic context Map 1 shows historic state boundaries, population density as well as the railway network (the main mode of transportation for Swiss emigrants) at 1870, the heyday of the Bührer emigration.