History, definition, and problems of medical geography: a general review. Report to the Commission on Medical Geography International Geographical Union 1952.
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Climate↗
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Alfred Haviland's nineteenth-century map analysis of the geographical distribution of diseases in England and Wales.
The nineteenth-century English physician Alfred Haviland used the national mortality statistics for England and Wales to develop an elaborate geographical explanation based on map analysis for the cause of heart, cancer, and tuberculosis deaths. He found that females had higher rates for all three causes of death. However, although his technique was innovative his analysis was flawed.
England↗
Finke's 1792 map of human diseases: the first world disease map?
Documentary evidence reveals that a German physician L.L. Finke produced a world map of diseases in 1792. This is much earlier than any world disease map previously known. Contrary to the contemporary literature in medical cartography this data proves that: (1) It was neither yellow fever nor cholera epidemics but indigenous diseases that were the catalyst for this earlier world disease map. (2) It predates Humboldt's influence on thematic mapping.
Epidemiology↗
Our sense of Snow: the myth of John Snow in medical geography.
In 1854, Dr. John Snow identified the Broad Street pump as the source of an intense cholera outbreak by plotting the location of cholera deaths on a dot-map. He had the pump handle removed and the outbreak ended...or so one version of the story goes. In medical geography, the story of Snow and the Broad Street cholera outbreak is a common example of the discipline in action. While authors in other health-related disciplines focus on Snow's "shoe-leather epidemiology", his development of a water-borne theory of cholera transmission, and/or his pioneering role in anaesthesia, it is the dot-map that makes him a hero in medical geography. The story forms part of our disciplinary identity. Geographers have helped to shape the Snow narrative: the map has become part of the myth. Many of the published accounts of Snow are accompanied by versions of the map, but which map did Snow use? What happens to the meaning of our story when the determinative use of the map is challenged? In his book On the Mode of Communication of Cholera (2nd ed., John Churchill, London, 1855), Snow did not write that he used a map to identify the source of the outbreak. The map that accompanies his text shows cholera deaths in Golden Square (the subdistrict of London's Soho district where the outbreak occurred) from August 19 to September 30, a period much longer than the intense outbreak. What happens to the meaning of the myth when the causal connection between the pump's disengagement and the end of the outbreak is examined? Snow's data and text do not support this link but show that the number of cholera deaths was abating before the handle was removed. With the drama of the pump handle being questioned and the map, our artifact, occupying a more illustrative than central role, what is our sense of Snow?
Cholera↗
Males and females scan maps similarly, but give directions differently.
After studying routes on a map, females tend to give directions that feature landmarks and left/right turns, whereas males include more cardinal and distance information. It is plausible this difference results from disparate attention to these features during exploration of a map. In the present study, 22 males and 22 females learned routes on a map while their eye movements were monitored, and then gave written directions between different locations. Consistent with earlier research, males made more references to NSEW when giving directions, whereas females referred mainly to left/right turns and landmarks along each route. However, these reporting biases were not related to differences in how the groups explored the maps, as females did not spend more time looking at landmarks, nor did either group spend more time looking at Euclidean cues. Thus, despite sexually dimorphic route descriptions, there was not dimorphic exploration or attention to the salient features.
Adolescent↗
Cluster analysis of structural stage classes to map wildland fuels in a Madrean ecosystem.
Geospatial information technology is changing the nature of fire mapping science and management. Geographic information systems (GIS) and global positioning system technology coupled with remotely sensed data provide powerful tools for mapping, assessing, and understanding the complex spatial phenomena of wildland fuels and fire hazard. The effectiveness of these technologies for fire management still depends on good baseline fuels data since techniques have yet to be developed to directly interrogate understory fuels with remotely sensed data. We couple field data collections with GIS, remote sensing, and hierarchical clustering to characterize and map the variability of wildland fuels within and across vegetation types. One hundred fifty six fuel plots were sampled in eight vegetation types ranging in elevation from 1150 to 2600 m surrounding a Madrean 'sky island' mountain range in the southwestern US. Fuel plots within individual vegetation types were divided into classes representing various stages of structural development with unique fuel load characteristics using a hierarchical clustering method. Two Landsat satellite images were then classified into vegetation/fuel classes using a hybrid unsupervised/supervised approach. A back-classification accuracy assessment, which uses the same pixels to test as used to train the classifier, produced an overall Kappa of 50% for the vegetation/fuels map. The map with fuel classes within vegetation type collapsed into single classes was verified with an independent dataset, yielding an overall Kappa of 80%.
Cluster Analysis↗
Evaluating factors influencing groundwater vulnerability to nitrate pollution: developing the potential of GIS.
The 1991 EU Nitrate Directive was designed to reduce water pollution from agriculturally derived nitrates. England and Wales implemented this Directive by controlling agricultural activities within their most vulnerable areas termed Nitrate Vulnerable Zones. These were designated by identifying drinking water catchments (surface and groundwater), at risk from nitrate pollution. However, this method contravened the Nitrate Directive because it only protected drinking water and not all waters. In this paper, a GIS was used to identify all areas of groundwater vulnerable to nitrate pollution. This was achieved by constructing a model containing data on four characteristics: the quality of the water leaving the root zone of a piece of land; soil information; presence of low permeability superficial (drift) material; and aquifer properties. These were combined in a GIS and the various combinations converted into a measure of vulnerability using expert knowledge. Several model variants were produced using different estimates of the quality of the water leaving the root zone and contrasting methods of weighting the input data. When the final models were assessed all produced similar spatial patterns and, when verified by comparison with trend data derived from monitored nitrate concentrations, all the models were statistically significant predictors of groundwater nitrate concentrations. The best predictive model contained a model of nitrate leaching but no land use information, implying that changes in land use will not affect designations based upon this model. The relationship between nitrate levels and borehole intake depths was investigated since there was concern that the observed contrasts in nitrate levels between vulnerability categories might be reflecting differences in borehole intake depths and not actual vulnerability. However, this was not found to be statistically important. Our preferred model provides the basis for developing a new set of groundwater Nitrate Vulnerable Zones that should help England and Wales to comply with the EU Nitrate Directive.
Agriculture↗
Within-state geographic patterns of health insurance coverage and health risk factors in the United States.
BACKGROUND: A number of health risk factors have been associated with the incidence and mortality of common diseases. Although knowing risk factor patterns at a small-area level would be useful for ecologic analyses and prevention program planning, risk factor data are generally published only at the state or regional level in the United States. This study presents maps of within-state patterns of several such factors. METHODS: Responses to Behavioral Risk Factor Surveillance System (BRFSS) questions about smoking, obesity, health insurance, and mammography use were aggregated for 1992-1998 by county. These data were then geographically smoothed by adjusting each county's proportional response based on the responses of its neighboring counties. RESULTS: The maps show risk factor patterns consistent with published state-level maps, but also identify within-state variations masked by aggregation to the larger geographic units. CONCLUSIONS: The risk factor maps presented should permit a better understanding of localized patterns of health risk behaviors and access to health care as well as help to target intervention activities in the U.S. areas that most need them.
Adult↗
Locating community health care centres in rural Saskatchewan: the case of the Living Sky Health District.
Using the Living Sky Health District in rural Saskatchewan as a sample case, this paper illustrates and discusses the use of location theory modelling tools as an aid to achieving high levels of efficiency coupled with administrator-determined levels of access. The paper begins by examining access issues as they affect location decisions. One of the empirical pillars of the paper is the well-documented idea that people will travel great distances in situations of acute circumstances, but are unwilling to travel far for important preventive care and monitoring of some chronic conditions. The study continues by presenting a non-technical overview of location theory which demonstrates the applicability of location modelling to the present problem; several possible location scenarios for Living Sky Health District are calculated, the most appropriate of which will depend on the goals and priorities of the district board. Finally, the study's results and more general conclusions are presented and discussed.
Catchment Area, Health↗
ARTMAP neural networks for information fusion and data mining: map production and target recognition methodologies.
The Sensor Exploitation Group of MIT Lincoln Laboratory incorporated an early version of the ARTMAP neural network as the recognition engine of a hierarchical system for fusion and data mining of registered geospatial images. The Lincoln Lab system has been successfully fielded, but is limited to target/non-target identifications and does not produce whole maps. Procedures defined here extend these capabilities by means of a mapping method that learns to identify and distribute arbitrarily many target classes. This new spatial data mining system is designed particularly to cope with the highly skewed class distributions of typical mapping problems. Specification of canonical algorithms and a benchmark testbed has enabled the evaluation of candidate recognition networks as well as pre- and post-processing and feature selection options. The resulting mapping methodology sets a standard for a variety of spatial data mining tasks. In particular, training pixels are drawn from a region that is spatially distinct from the mapped region, which could feature an output class mix that is substantially different from that of the training set. The system recognition component, default ARTMAP, with its fully specified set of canonical parameter values, has become the a priori system of choice among this family of neural networks for a wide variety of applications.
Computer Simulation↗
Spatial registration of digital brain atlases based on fuzzy set theory.
We present a semiautomatic method based on fuzzy set theory for adjusting a computerized brain atlas to magnetic resonance images (MRIs) of the human cerebral cortex. The atlas was registered to three-dimensional MRI data sets of 10 healthy volunteers. After a global matching using the external contour of the brain, several local procedures were performed regarding selected primary furrows and cytoarchitectonic areas. The final transformation matrix was calculated with respect to these anatomical structures and to their local matrices. Evaluation revealed an increase in accuracy as expressed by a reduction of the visible mismatch with respect to the registration of cortical and subcortical brain structures.
Atlases as Topic↗
Neuromuscular disorders: gene location.
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Bibliographies as Topic↗
Congenital myasthenic syndromes: gene mutations.
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Bibliographies as Topic↗
Life and death of the people of London: a historical GIS of Charles Booth's inquiry.
Social reformer Charles Booth undertook a massive survey into the social and economic conditions of the people of London at the end of the 19th century. An important innovation of his Inquiry was the construction of large, detailed maps displaying social class of inner London on a street-by-street basis. These provide a detailed and vivid picture of the geography of poverty and affluence at this time. These maps have been digitised, georeferenced and linked to contemporary ward boundaries allowing Booth's measurement of social class to be matched to the measurement of social class in the 1991 census of population and standardised mortality ratios derived for all causes of death in the survey area between 1991 and 1995. The social class data were used to derive an index of relative poverty for both time periods and a comparison of the geographies of relative poverty and their relationship with contemporary mortality was made. Although the overall standard of living had increased, the geography of poverty at the end of the 19th century was very similar to that at the end of the 20th century. Moreover, the geography of all causes of death for people over the age of 65 was more strongly related to the geography of poverty in the late 19th century than contemporary patterns of poverty. This relationship was also true for mortality for specific diseases that are related to deprivation in early life. The paper concludes that the spatial patterns of poverty in inner London are extremely robust and a century of change has failed to disrupt it.
Cause of Death↗
Mapping high or low mortality places across time in the United States: a research note on a health visualization and analysis project.
This research note reports progress in visualizing and analyzing United States mortality data at the county level. The data visualization technique employed here may be applicable to other research situations. We dichotomized the range of mortality rates into high or low mortality counties, mapped them, and explored the clustering of high or low mortality rate counties across both space and time. We find visual evidence that high or low mortality counties spatially cluster together during individual periods of time (5 years). We find further visual evidence that there is a spatial persistence over time (30 years) of these counties with high or low mortality. This evidence leads us to conclude that relatively high or low mortality is anchored over time within a spatial region and population, suggesting that research efforts may be focused on these clusters to assess local causes of high or low mortality rates. Future research will examine the permanence of the resident population (i.e., population mixing), characteristics of the resident population, and characteristics of their place of residence over time.
Geography↗
On the use of contour maps in the analysis of spread of communicable disease.
The co-ordinates of the dwellings where cases of variola minor (alastrim) occurred during a small epidemic were used in a worked example of contour mapping of disease spread. The contoured variable was the date of onset, relative to an arbitrary base date, of the case introducing the disease into each of twenty-two households. Three contour maps prepared with slightly different computer programmes or dates exhibited similar concentric loops whose centres were close to the first infected household. The average rate of spread of the disease was estimated by regression of the number of days to onset of the first case in the household on the average distance from an arbitrary origin to the relevant contour line. The calculated average rate of spread was 1.22 metres per day. An additional map was contoured using the cumulative number of cases as the contoured variable, relative to the onset of the example epidemic.
Brazil↗
The Hampshire epidemic of foot-and-mouth disease, 1967.
An analysis was made of the spread of foot-and-mouth disease during the epidemic in Hampshire in January and February 1967. To explain the pattern of spread, it had to be postulated that virus was present seven days before the first outbreak was reported. It is suggested that the disease occurred initially in pigs fed on infected meat and that the virus was subsequently disseminated from the local abattoir, where the pigs were killed, to four farms by movement of animals, slaughterhouse waste, people or vehicles, and to fifteen by the airborne route. Subsequent spread from these farms was by movement in two instances and by the airborne route in five. The source and route of infection of the last farm in the outbreak were not determined.The risk of spread through movement was associated more with carriage of infected slaughterhouse waste, movement of animals, people or vehicles carrying animals than through collection of milk, artificial insemination or movement of other types of vehicles. Outbreaks of disease among pigs gave rise to more secondary spread than outbreaks in cattle. Secondary outbreaks attributed to airborne spread occurred only in ruminants. Most airborne spread was into areas of high livestock density and cattle in the larger herds became infected. Airborne spread could be correlated with wind direction and speed but not with rain. The reduction in the number of outbreaks at the end of the epidemic could be attributed to the elimination of the largest sources of virus, the control of movements and the fact that in all instances except two the wind was blowing virus over towns and out to sea, to areas of low stock density and to areas where animals had been killed.
Abattoirs↗
Skulls, brains, and memorial culture: on cerebral biographies of scientists in the nineteenth century.
In this paper, I will argue that the scientific investigation of skulls and brains of geniuses went hand in hand with hagiographical celebrations of scientists. My analysis starts with late-eighteenth century anatomists and anthropologists who highlighted quantitative parameters such as the size and weight of the brain in order to explain intellectual differences between women and men and Europeans and non-Europeans, geniuses and ordinary persons. After 1800 these parameters were modified by phrenological inspections of the skull and brain. As the phrenological examination of the skulls of Immanuel Kant, Wilhelm Heinse, Arthur Schopenhauer and others shows, the anthropometrical data was interpreted in light of biographical circumstances. The same pattern of interpretation can be found in non-phrenological contexts: Reports about extraordinary brains were part of biographical sketches, mainly delivered in celebratory obituaries. It was only in this context that moral reservations about dissecting the brains of geniuses could be overcome, which led to a more systematic investigation of brains of geniuses after 1860.
Biographies as Topic↗