Nigel Waters

Accuracy of city postal code coordinates as a proxy for location of residence

BackgroundHealth studies sometimes rely on postal code location as a proxy for the location of residence. This study compares the postal code location to that of the street address using a database from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH©). Cardiac catheterization cases in an urban Canadian City were used for calendar year 1999. We determined location in meters for both the address (using the City of Calgary Street Network File in ArcView 3.2) and postal code location (using Statistic Canadas Postal Code Conversion File).ResultsThe distance between the two estimates of location for each case were measured and it was found that 87.9% of the postal code locations were within 200 meters of the true address location (straight line distances) and 96.5% were within 500 meters of the address location (straight line distances).ConclusionsWe conclude that postal code locations are a reasonably accurate proxy for address location. However, there may be research questions for which a more accurate description of location is required.

THE EFFECTS OF HIGHWAY TRANSPORTATION CORRIDORS ON WILDLIFE: A CASE STUDY OF BANFF NATIONAL PARK

Road fragmentation is a concern for wildlife viability in and adjacent to protected areas in the Rocky Mountains. Roads create a barrier to wildlife movement and have documented demographic effects, including the alteration of animal communities, the reduction of biological diversity, and the increased threat of extinction. Wildlife movement across and adjacent to the Trans-Canada Highway (TCH) (14,000 annual average daily traffic, AADT) and Highway 1A (3000 AADT) was studied in Banff National Park, Alberta. Animal tracks were observed crossing roadways and on transects adjacent to roads for wolves, cougar, lynx, wolverine, marten, elk, deer, sheep, hare, and red squirrel relative to road types. Data were analyzed to assess the barrier effect and a geographical information system (GIS) was used to identify landscape attributes associated with species movement. The TCH was found to be a barrier to movement for all species. In less perturbed environments, it was observed that movement patterns for the wildlife communities were spatially continuous and that individual species movement was complex. This movement was not observed across the TCH. An interpolation of point data showed sites of high crossing frequency within the continuum of crossing points. These sites ranged from 250 to 2000 m in diameter. General predictors for movement by aspect were found to be the south, southwest and west facing slopes. Flat slopes, areas of low topographic complexity, and slopes lower than 5° were also effective predictors of animal movements. The data suggest that maintaining contiguous tracts of habitat with the above attributes facilitate normal wildlife movement most effectively. Mitigation that approximates previous patterns can be achieved only by elevating and/or burying extensive sections of highway.

Determining geographic areas and populations with timely access to cardiac catheterization facilities for acute myocardial infarction care in Alberta, Canada

BackgroundThis study uses geographic information systems (GIS) as a tool to evaluate and visualize the general accessibility of areas within the province of Alberta (Canada) to cardiac catheterization facilities. Current American and European guidelines suggest performing catheterization within 90 minutes of the first medical contact. For this reason, this study evaluates the populated places that are within a 90 minute transfer time to a city with a catheterization facility. The three modes of transport considered in this study are ground ambulance, rotary wing air ambulance and fixed wing air ambulance.MethodsReference data from the Alberta Chart of Call were interpolated into continuous travel time surfaces. These continuous surfaces allowed for the delineation of isochrones: lines that connect areas of equal time. Using Dissemination Area (DA) centroids to represent the adult population, the population numbers were extracted from the isochrones using Statistics Canada census data.ResultsBy extracting the adult population from within isochrones for each emergency transport mode analyzed, it was found that roughly 70% of the adult population of Alberta had access within 90 minutes to catheterization facilities by ground, roughly 66% of the adult population had access by rotary wing air ambulance and that no population had access within 90 minutes using the fixed wing air ambulance. An overall understanding of the nature of air vs. ground emergency travel was also uncovered; zones were revealed where the use of one mode would be faster than the others for reaching a facility.ConclusionCatheter intervention for acute myocardial infarction is a time sensitive procedure. This study revealed that although a relatively small area of the province had access within the 90 minute time constraint, this area represented a large proportion of the population. Within Alberta, fixed wing air ambulance is not an effective means of transporting patients to a catheterization facility within the 90 minute time frame, though it becomes advantageous as a means of transportation for larger distances when there is less urgency.

Using Twitter for tasking remote-sensing data collection and damage assessment: 2013 Boulder flood case study

ABSTRACT A new methodology is introduced that leverages data harvested from social media for tasking the collection of remote-sensing imagery during disasters or emergencies. The images are then fused with multiple sources of contributed data for the damage assessment of transportation infrastructure. The capability is valuable in situations where environmental hazards such as hurricanes or severe weather affect very large areas. During these types of disasters it is paramount to ‘cue’ the collection of remote-sensing images to assess the impact of fast-moving and potentially life-threatening events. The methodology consists of two steps. First, real-time data from Twitter are monitored to prioritize the collection of remote-sensing images for evolving disasters. Commercial satellites are then tasked to collect high-resolution images of these areas. Second, a damage assessment of transportation infrastructure is carried out by fusing the tasked images with contributed data harvested from social media such as Flickr and Twitter, and any additional available data. To demonstrate its feasibility, the proposed methodology is applied and tested on the 2013 Colorado floods with a special emphasis in Boulder County and the cities of Boulder and Longmont.

Dietary Intake Measured from a Self-Administered, Online 24-Hour Recall System Compared with 4-Day Diet Records in an Adult US Population

The objective of this study was to compare nutrient intake of two 24-hour recalls collected using the Automated Self-Administered 24-Hour Dietary Recall to a 4-day food record. A convenience sample of university-affiliated adults was chosen because of the diverse population at this university. Ninety-three participants completed the 4-day record and were then prompted to complete two 24-hour recalls within 2 weeks after. Pearson correlation coefficients were calculated for nutrient intake and Healthy Eating Index 2005 (HEI-2005), a summary measure of diet quality. Nutrients and HEI-2005 were also divided into quartiles and percent agreement and κ values were calculated. Results indicated that mean nutrient intakes were similar across the recall and record. Pearson correlations comparing the record and recall ranged from 0.16 to 0.78; with most correlations being between 0.4 and 0.6. For quartiles of dietary intake, percent agreement was moderately high (62.6% to 79.8%), with low to moderate κ values (κ=0.11 to 0.52). The 24-hour recall provided a good overall ranking of intake compared to a 4-day food record. Overall correlations and percent agreement were moderate across the nutrients and HEI-2005, suggesting that the 24-recalls may have been capturing different information than the food record in our population. Individual researchers will need to weigh the benefits of a more automated system, such as efficiency, against the potential loss of food item detail and potential need for larger sample sizes, for their particular study populations.

Risk factors associated with human Rift Valley fever infection: systematic review and meta-analysis.

To identify risk factors for human Rift Valley fever virus (RVFV) infection.

A Multi‐Objective, Multi‐Criteria Approach to Improve Situational Awareness in Emergency Evacuation Routing Using Mobile Phone Data

Emergency services personnel face risks and uncertainty as they respond to natural and anthropogenic events. Their primary goal is to minimize the loss of life and property, especially in neighborhoods with high population densities, where response time is of great importance. In recent years, mobile phones have become a primary communication device during emergencies. The portability of cell phones and ease of information storage and dissemination has enabled effective implementation of cell phones by first responders and one of the most viable means of communication with the population. Using cellular location data during evacuation planning and response also provides increased awareness to emergency personnel. This article introduces a multi-objective, multi-criteria approach to determining optimum evacuation routes in an urban setting. The first objective is to calculate evacuation routes for individual cell phone locations, minimizing the time it would take for a sample population to evacuate to designated safe zones based on both distance and congestion criteria. The second objective is to maximize coverage of individual cell phone locations, using the criteria of underlying geographic features, distance and congestion. In summary, this article presents a network-based methodology for providing additional analytic support to emergency services personnel for evacuation planning.

TEACHING THE NCGIA CURRICULUM IN PRACTICE: ASSESSMENT AND EVALUATION

The implementation in the Department of Geography at the University of Calgary of the NCGIAs Core Curriculum for GIS teaching is described. The core curriculum was taught using the two semester, year long option during the 1989-90 academic year. Labs, software and hardware used in association with the two courses are discussed. Plans for implementing the curriculum in the 1990-91 academic year are explained and seek to draw upon the successes and failures encountered during the previous year.

A validation of ground ambulance pre-hospital times modeled using geographic information systems

BackgroundEvaluating geographic access to health services often requires determining the patient travel time to a specified service. For urgent care, many research studies have modeled patient pre-hospital time by ground emergency medical services (EMS) using geographic information systems (GIS). The purpose of this study was to determine if the modeling assumptions proposed through prior United States (US) studies are valid in a non-US context, and to use the resulting information to provide revised recommendations for modeling travel time using GIS in the absence of actual EMS trip data.MethodsThe study sample contained all emergency adult patient trips within the Calgary area for 2006. Each record included four components of pre-hospital time (activation, response, on-scene and transport interval). The actual activation and on-scene intervals were compared with those used in published models. The transport interval was calculated within GIS using the Network Analyst extension of Esri ArcGIS 10.0 and the response interval was derived using previously established methods. These GIS derived transport and response intervals were compared with the actual times using descriptive methods. We used the information acquired through the analysis of the EMS trip data to create an updated model that could be used to estimate travel time in the absence of actual EMS trip records.ResultsThere were 29,765 complete EMS records for scene locations inside the city and 529 outside. The actual median on-scene intervals were longer than the average previously reported by 7–8 minutes. Actual EMS pre-hospital times across our study area were significantly higher than the estimated times modeled using GIS and the original travel time assumptions. Our updated model, although still underestimating the total pre-hospital time, more accurately represents the true pre-hospital time in our study area.ConclusionsThe widespread use of generalized EMS pre-hospital time assumptions based on US data may not be appropriate in a non-US context. The preference for researchers should be to use actual EMS trip records from the proposed research study area. In the absence of EMS trip data researchers should determine which modeling assumptions more accurately reflect the EMS protocols across their study area.

Risk analysis for dengue suitability in Africa using the ArcGIS predictive analysis tools (PA tools).

BACKGROUND Risk maps identifying suitable locations for infection transmission are important for public health planning. Data on dengue infection rates are not readily available in most places where the disease is known to occur. METHODS A newly available add-in to Esris ArcGIS software package, the ArcGIS Predictive Analysis Toolset (PA Tools), was used to identify locations within Africa with environmental characteristics likely to be suitable for transmission of dengue virus. RESULTS A more accurate, robust, and localized (1 km × 1 km) dengue risk map for Africa was created based on bioclimatic layers, elevation data, high-resolution population data, and other environmental factors that a search of the peer-reviewed literature showed to be associated with dengue risk. Variables related to temperature, precipitation, elevation, and population density were identified as good predictors of dengue suitability. Areas of high dengue suitability occur primarily within West Africa and parts of Central Africa and East Africa, but even in these regions the suitability is not homogenous. CONCLUSION This risk mapping technique for an infection transmitted by Aedes mosquitoes draws on entomological, epidemiological, and geographic data. The method could be applied to other infectious diseases (such as Zika) in order to provide new insights for public health officials and others making decisions about where to increase disease surveillance activities and implement infection prevention and control efforts. The ability to map threats to human and animal health is important for tracking vectorborne and other emerging infectious diseases and modeling the likely impacts of climate change.