In John Snow determined the source of a cholera outbreak in London by marking points on a map depicting where the cholera victims lived, and connecting the cluster that he found with a nearby water source. This was one of the earliest successful uses of a geographic methodology in epidemiology. While the basic elements of topography and theme existed previously in cartographythe John Snow map was unique, using cartographic methods not only to depict but also to analyze clusters of geographically dependent phenomena. This work was originally drawn on glass plates but later plastic film was introduced, with the advantages of being lighter, using less storage space and being less brittle, among others.
Assessment Information source, data display Considering land form, slope, land use, vegetation cover, and wind direction, what area is likely to be affected if this volcano erupts?
How many people could be affected? Index of information List all available hospitals located not within 30 km radius of the volcano Status reporting Periodic assessment of volcanic activity Monitoring change How has the savanna desert boundary changed in the last 5 years?
What changes in climate and land use could account for the on-going desertification process? Analysis Research support What factors determine landslide activity in this area? According to these factors, what zones are susceptible to landslides? Forecasting What population centers are likely to be affected by this hurricane?
What is the most likely lava flow path in case a volcanic eruption occurs? Policy development What areas in this growing urban region should be restricted to low-density development?
Aid allocation Where should mitigation strategies be prioritized? Project evaluation If erosion trends continue, what will be the economic impact on the project? What are the costs and benefits of instituting or not instituting erosion control measures?
The situation has since been aggravated by increasing rural migration, frequently occupying steep areas of questionable stability.
City officials had two urgent tasks: By entering data on land use, landslide hazard susceptibility, topography, slope, and protected areas, a GIS database was created to identify areas potentially suitable for expansion. City officials could then set minimum criteria for areas of new development i.
Using the GIS, areas meeting the criteria could be identified. The number of people living in extreme and high landslide hazard areas could also be determined, providing the basis for selecting priority areas for implementing prevention measures relocation, construction, retrofitting, etc.
For this exercise, the advantages of using GIS as compared to manual mapping techniques are obvious. Not only does GIS afford great time savings for the overlay, display, assessment, and analysis of hazardous areasbut GIS also offers flexibility in selecting the minimum standards.
Tentatively selected standards can be tested for feasibility and adjusted. Using a GIS, this process would take minutes, while with manual methods, it would take a week of redrafting and recalculations In a landslide study for example, data on slope steepness, rock composition, hydrology, and other factors can be combined with data on past landslides to determine the conditions under which landslides are likely to occur see Chapter To analyze all possible combinations with manual techniques is a virtually impossible task; thus, typically only two factors are analyzed, and the composite units are combined with the landslide inventory map.
With GIS, however, it is possible to analyze an almost unlimited number of factors associated with historical events and present conditions, including present land use, presence of infrastructure, etc.
The resultant landslide hazard zonation map provides planners with a designation of the degree of landslide propensity for any given area. For floods, GIS and remotely-sensed data can be used to identify flood-prone areas, map floods in progress, delineate past floods, and predict future ones see Chapters 4 and 8.
GIS can combine information on slope, precipitation regimes, and river carrying capacity to model flood levels. Synthesis information obtained from such an integrated study can help planners and decision-makers determine where to construct a dam or reservoir in order to control flooding.
Likewise, a map depicting volcano locations may be entered into the GIS; volcano attributes such as periodicity, explosivity index VEIpast effects, and other attributes may be ascribed to each volcano record in a relational database.
Finally, information on other hazards can be combined to create new sub-sets of data, each one complying with different pre-established minimum standards for development. GIS Applications at the Local Level At this level, GIS can be used in prefeasibility and feasibility sectoral project studies and natural resource management activities to help planners identify specific mitigation measures for high-risk investment projects and locate vulnerable critical facilities for the implementation of emergency preparedness and response activities.
In population centers, for example, large scale GIS databases resolutions of m2 per cell or less can display the location of high-rise buildings, hospitals, police stations, shelters, fire stations, and other lifeline elements.
By combining these data with the hazards assessment map-previously collected or generated through GIS-planners can identify critical resources in high-risk areas and adequately formulate mitigation strategies.
When equitable distribution of land is defined in terms of earning capacity instead of parcel size, land capability and management practices have to be factored into the equation. Eight maps were coded into the system: Three synthesis maps were produced by overlaying present land use with land capability, present land use with erosion risk, and the development strategy with erosion risk.
The GIS exercise showed that large commercial parcels occupied 76 percent of ail the lands suitable for unrestricted or moderately restricted cultivation, while 99 percent of the land occupied by small farms was classified as severely restricted or worse.
This modest GIS exercise, using readily available information, constituted a tiny fraction of the overall study, yet it demonstrated clearly that land redistribution would be required to achieve the project's objective of equitable distribution, and provided the data required to guide the redistribution and to introduce improved soil management practices.
The decision on the type of information to be used for depicting the variables included in the database-whether real-scaled or symbolic dimensions-becomes a critical decision at this level. Real-scaled data should prevail over symbolic information, especially at this level of planning, when precise information is required to assess the risk posed to specific investment projects.S1 E2 The Son of God Unpacking the unique Kim father-son relationship further, “Son of God” tracks the decline of Kim Il Sung and the rise of his son, Kim Jong Il.
Explore the world of Geographic Information Systems (GIS) and how it's being used to solve real world problems in this introductory course.
Learn about data models, file formats, and geodatabases. What is Geographic Information Systems (GIS)? GIS is a system that collects, displays, manages and analyzes geographic information. Geographic Information Systems is a computer-based tool that analyzes, stores, manipulates and visualizes geographic information, usually in a map.
storage and analysis of spatial data in a Geographic. Geographic Information System (GIS) Which School Should Your Child Attend? Miami-Dade County Public Schools' geographic information system (GIS) informs users of school assignments for students based on the entry of a street address and zip code.
Geography is central to the work of the Census Bureau, providing the framework for survey design, sample selection, data collection, tabulation, and dissemination. The Environmental Data Center is the center of technical expertise in GIS for the state of Rhode Island. The (EDC) is a Geographic Information System (GIS) and spatial data analysis laboratory in the University of Rhode Island's Department of Natural Resources Science, College of the Environment and Life Science..
Major areas of research at the EDC are spatial data modeling, ecological mapping.