Nuckols et al. 2011

• Geospatial science • Environmental science • Epidemiology

Systematic study of geographic variables relating to, occupying, or having the character of space

Grid cells serve as basic units of analysis

Uses points, lines, or polygons based on continuous geometry of space to represent data

Representing elevation data often used for terrain analysis

Traditional map scale ratio Relates the size of feature in life to size on map

Size of study area Different results based on study area (rate of caner in county vs. province)

Grain or smallest unit distinguishable Map data at different scales will allow for resolution of different objects Resolution is chosen based on whats needed

Scale at which process of interest occurs Can be resolution dependent (detected at one scale but not another)

How well GIS data represents reality in terms of positional, attribute and temporal accuracy

Agreement between data representation in GIS and actual location of data on ground (ground truth)

Measure of how well information linked to the data representation format is correct

Appropriateness of using particular snapshot or snapshots of time for GIS analysis or modelling effort

Source errors: accuracy of data (differences between data and reality) Processing errors: introduced into database resulting from GIS-based analysis and modelling

Systematic study of the complex physical, chemical and biotic factors that act upon an organism or ecologic community and ultimately determine its form and survival

To supplement measurement data Based on statistical probability

To supplement measurement data Based on physical processes

Application of environmental science to exposure assessment for epidemiology Association between contaminant source and exposure cannot exist unless there is a plausible geophysical route of transport between source and receptor

Errors in classifying exposure Exposure metric is at population level and individual exposures vary because of different activity patterns

Errors in classifying exposure Exposure metric used in study is measured with error and is imperfect surrogate for true exposure

Ability of exposure metric to correctly classify as exposed those who are truly exposed

Ability of exposure metric to correctly classify as unexposed those who are unexposed

Function of the occurrence of the target agent in a specified environmental medium Allows assessment of likelihood of exposure across study population and route of exposure data needed to calculate personal exposure

Simulation model which accurately reflected hydraulic characteristics of ground water regime in area