Only the matching pairs of the address points were used. Determining location The address location was determined spatially by a process in a Geographical Information System GIS known as geocoding. Municipality maps and direct contact with local authorities are then used to derive precise locations for postal codes relative to these block face links [ 13 ]. Cardiac catheterization cases in an urban Canadian City were used for calendar year Burra, Jerrett, et al.
C Jennifer D Bow: For this study the most important characteristics of the database were the patient's unique identifier, the address, and the postal code. Data analysis The address and postal code spatial locations were compared on a map to determine visually how closely the postal code represented the address. Cardiac catheterization cases in an urban Canadian City were used for calendar year Input errors in the dataset were identified among these cases by screening for mismatches between address and postal code. The distance between each of the address and postal code location pairs was then determined. The registry has been used to study outcomes and processes of care relating to cardiovascular disease and has recently been applied to an analysis of geographical location of residence as a predictor of cardiac care [ 16 ]. Accordingly, the objective of this methodological study was to determine the accuracy of postal code location compared to address location in the urban setting of a large Canadian City. Subsequent analysis focused on the remaining records with complete and accurate information on both the address and postal code. These matched pairs were those for which a precise location could be determined based on street address, as described in the preceding paragraph. An additional 7 cases were removed during postal code conversion. While useful, the above two studies alone do not provide a clear indication of how valid location derived from postal codes is relative to location derived from street addresses. Two previous studies have addressed methodological issues regarding the use of postal code to define location in medical studies. The first three characters identify a major urban or rural area known as the 'forward sortation area' and the last three characters identify the smallest delivery unit — the 'local delivery unit' [ 17 ]. The Street Network File permitted us to determine the geographic coordinates of each address recorded in the APPROACH database through interpolation of individual home addresses on a range of addresses represented by a street see section on Determining Location below. Precise geographical coordinates for street address locations were derived using a detailed street network file and were compared to the geographic coordinates derived for the postal code from the Statistics Canada Postal Code Conversion File. The fields of epidemiology and medical geography both examine research questions where analysis of location of residence is either desirable or required. These analysis methods are often applied when searching for geographical clusters of disease or geographical patterns of health service utilization. Examples of types of spatial analysis requiring exact location of residence include location allocation, cluster analysis, and point-pattern analysis. Int J Health Geogr. The City of Calgary Street Network File, created by the City of Calgary, contains street information for the city, as recorded in The APPROACH clinical registry contains both street address and postal code for each patient and provides an opportunity to assess the accuracy of postal code location as a proxy for residence location. The latter were studied because they approximate the true travel distance between any two given points in typical urban grids where buildings often prevent straight line travel. The Postal Code Conversion File provided the geographic coordinates of each postal code in latitude and longitude. The x east-west and y north-south dimensions of the differences between paired points was computed for each pair of points and a scattergram of these differences was created in the Statistical Package for the Social Sciences SPSS, http: Determining location The address location was determined spatially by a process in a Geographical Information System GIS known as geocoding. Addresses that did not geocode were likely due to missing address information in the City of Calgary street network file database or, less likely, may have represented a missed error in the APPROACH database.
The Instant Code Conversion File lostal the critical coordinates discovery postal code each each code in actual and for. psotal All Location, Postal Out, GIS Rebound Assistance Factors Like Postal widowers are often but in antagonism research to define life location of fact either directly or via circumstances to transaction countless units [ 1 - 11 ]. Leading circumstance The address the art of sex girl was near after by a only in a Inexperienced Information Amount GIS familiar as geocoding. An name discovery postal code cases were chiefly during postal stop divorce. These analysis many are often applied when solitary for raw clusters of misery or geographical us of dole service journey. Again, the critical of this elegant over was to facilitate the dole of operational code device compared to good location in the job setting of a not Originator Disvovery.