Alabama is a ‘Deep South’ state and its Black Belt, shown as a dashed white line in Figure 1, is covered with dark rich soils that stretch across the state’s midsection attracting a plantation system of agriculture and slavery. After the end of slavery, lynching in southern and neighbouring states was used to control black people who were often feared and hated. Lynchings – open public murders of individuals suspected of crimes – were often carried out by mobs in spontaneous fashion. The clustering of executions and lynchings is of extreme interest in that the same cultural norms and social control mechanisms, when justified by legal codes, served to subjugate blacks by death penalty laws and informal illegal executions. The shifting geographies of executions and lynchings that occurred from 1871 to 1930 can only be understood in the context of historical events that took place in Alabama and beyond its borders prior to and after emancipation. GIS proved to be a useful tool in revealing these shifts.

Textbox:
Sweet Home Alabama
The death penalty was widely used in the South. Prior to 1865, blacks account-ed for well over 90% of all executions (see Figure 1) and were subject to death penalty statues not applicable to whites. Moreover, the majority of those executed were slaves, and slave-owners were often paid compensation for their loss. After slavery was abolished the old social order attempted to maintain control over free men once considered as private property; blacks were not only executed at a higher rate than during the slave era, they also became the targets of lynching violence which increased around 1870 and continued up until 1927, when the state centralised executions. Lynching as a form of social control was unique to the US. Most lynchings were carried out by hanging or shooting, but some incidents involved burning, dismemberment, castration, and torture. By and large, all were sadistic and race-driven attempts to maintain a caste system based upon skin colour. Lynching produced fear and thus proved an effective method of social control; whites, albeit few, were also lynched in Alabama.

Spatial Data
The spatial data used in the study includes boundaries of county, territory, and state of Alabama for the decades from 1820 to 2000. County boundaries were digitised using historical maps for decades from 1820 to 1910. These maps were first converted to uncompressed Tiff format and geo-referenced using an image-to-map method. To ensure integrity of shared boundaries, the digitising began with the most recent boundaries, working back in time by decade. After verification, county features from each decade were output as a feature class for the preceding decade. Area changes were corrected by modify–ing geometry for arcs within each boundary to agree with georeferenced maps. For the post-1910 period the year 2000 boundaries were adopted because county boundaries had undergone little change since 1910. They were filtered from an Access database containing census 2000 data and county areas for the entire US by attribute query and exported to a new database.

Non-spatial Data
Non-spatial data was gathered from two primary sources: “Espy File” and data from the “Hal Project” (Historical American Lynching Data Collection Project). The Espy File is a database of civil executions performed in the US, earlier New World colonies, and territories for the period from 1608 to 1987. The original data is provided on the Internet in tabular form, with each execution listed as an individual record in Adobe Acrobat format. The attributes include name, age, race, sex, occupation, crime, execution date, execution method, and location by county. The Espy File reports 302 executions for the period from 1871 to 1930 in Alabama and the ‘Hal Project’ database is a registry of lynchings in the US. The Hal data was compiled using NAACP (National Association for the Advancement of Colored People) Lynching Records housed at Tuskegee University in Tuskegee, Alabama. This data includes three hundred lynchings from 1871 to 1930 in the state of Alabama. The original data is provided in tabular form, with each lynching listed as a single record. The attributes include name, age, race, sex, alleged crime, date of lynching and location by county within Alabama. Race was, at the county level, considered the most informative attribute for both the ‘Espy File’ and the Hal data.

Method
Conversions of map entities from vector to raster format and grid surface analyses of z-values based upon incident frequencies were completed in GeoMedia Professional 6.0. Microsoft Excel was used as the initial workspace to standardise the data. The data was ultimately integrated into a Microsoft Access database connected to the GIS that included feature tables for state, county, and incident information. To better understand the geography of social control in Alabama during the period of overlap from 1871 to 1930 we used the GIS to track changes by decade from 1831 to 1930 in the distribution and frequency of four variables:
- total population by county
- percentage of population by county represented by slaves during the slave era and black persons thereafter
- total executions by county
- total lynchings by county.

Results
The GIS analysis of executions and lynchings confirm the correlation among factors such as race, county location, and demographics. Furthermore, the GIS revealed strong correlations between executions and lynchings in counties not directly under state control, where both forms were sanctioned either legitimately or illegitimately. Local situational cultural factors fuelled violence against the minority population, causing an increase in executions as lynchings declined. The eventual decline of both was achieved most significantly by the centralisation of executions initiated by the State of Alabama in 1927. Alabama was not unique in that all former confederate states experienced a similar corollary of executions and lynching. Both types of social control are, however, a reflection of a subculture of violence wherein these methods were determined more by cultural factors following slavery and emancipation.

Concluding Remarks
The authors plan to extend this study to include lynchings, executions and demographics for all 3,141 counties or county equivalents in the fifty US states and one Federal District.

Acknowledgements
Software and support were provided by the Intergraph Corporation’s Registered Research Laboratory (RRL) Program.

Further Reading
- W. Espy and J. O. Smykla. 1987. Executions in the United States, 1608-1987: The Espy File. Inter-University Consortium for Political and Social Research. Ann Arbor, Michigan.