GeoWorld October 2011

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The Universal Key for Unlocking GIS' Full Potential BEYONDMAPPING G BY JOSEPH BERRY eotechnology is rapidly changing how we perceive, process and provide spatial infor- mation. It's generally expected that anyone with an Internet connection can click anywhere in the world and instantly access images and basic information about a location. However, accessing your own specialized and proprietary data is much more dif- ficult—often requiring wholesale changes to a corporate database and staffing. The emergence of Geo-Web Applications involving the integration/ interaction of GIS, visualization and social media has set the stage for entirely new perspectives on corporate database management systems (DBMSs). For example, one can upload sales figures for individual customers into Google Earth and view them as clusters of pins draped on an aerial image of a city, or receive GPS-tagged photos of potholes on county roads, or track shipments and field crews, or locate vacant parking spaces at a mall—all this and more from a somewhat overly smart cell phone. Generally speaking, there are three information- processing modes: 1. Visualize—To recall or form mental images or pictures involving map display (charting capabilities). 2. Synthesize—To form a material or abstract entity by combining parts or ele- ments involving the re-packaging of existing information (geo-query capabilities). 3. Analyze—To separate a material Joseph Berry is a principal in Berry & Associates, consultants in GIS technology. He can be reached via e-mail at 10 or abstract entity into constituent parts or elements to determine their relation- ship involving deviation of new spatial information identifying key factors, con- nections and associations (map-analysis capabilities). Map analysis is by far the least devel- oped of the three. Visualization and query of mapped data are direct extensions of our paper-map and filing-systems legacy. Analysis of mapped data, however, involves somewhat unfamiliar territory for most organizations. GEO W ORLD / OCT O BE R 2O11 Figure 1. The lat/long coordinate system forms a comprehensive grid covering the entire world with cells of about half a foot or less over the continental United States. Like the "chicken and the egg" quandary, the demand for map analysis hasn't been there, because prior experience with map analysis hasn't been there. But even more basic is the lack of mapped data in a form amenable for analysis. Your grade-school exposure to geography and mapping can change all that. Recall that latitude (north/south) and longitude (east/west) lines can be drawn on the globe to identify a location anywhere in the world. Using typical single-precision floating-point storage of lat/long coordinates in a standard data- base enables grid-cell referencing of about half a foot or less anywhere in the continental United States (365,214 feet/degree * 0.000001 = 0.365214 feet * 12 = 4.38257-inch grid precision along the equa- tor). So appending lat/long fields to any database record locates that record with more than enough precision for most map-analysis applications. Lat/Long Basics As review, recall that the lat/long coordinate system uses solid angles measured from Earth's center (Figure 1). A line passing through the Royal Observatory in Greenwich, United Kingdom, near London (termed the Prime Meridian), serves as the international zero-longi- tude reference. Locations to the east are in the eastern hemisphere, and places to the west are in the western hemisphere, with each half divided into 180 degrees. Geographic latitude measures the angles from the equator to the poles that trace circles on Earth's surface called parallels, as they're parallel to the equator and each other. The equator divides the globe into Northern and Southern Hemispheres— 0 to 90° North and 0 to 90° South. Figure 1 shows

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