2.1. Common Mapping Tasks

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The process that produces a map requires three basic tasks: quantifying observations, locating the position of your observations, and visualizing the locations on a map. Digital tools have made these tasks more efficient and more accurate.


Quantifying observations

Measuring equipment such as laser range finders or imaging satellites provide discrete measurements that are less affected by personal interpretations. Traditional observations, such as manual photo interpretation or drawing features by hand, tend to introduce a biased view of the subject.


Locating positions of observations

Geographic referencing tools such as GPS receivers link on-the-earth locations to common mapping coordinate systems such as latitude and longitude. They calculate the receiver's location using satellite-based signals that help the GPS receiver calculate its location relative to satellites whose positions are well known. They act as a type of digital benchmark rather than using traditional survey or map referencing (best guess) methods. Traditional astronomical measurements or ground-based surveying techniques were useful but we now have common, consistent, and unbiased methods for calculating location.


Visualizing these locations on a map

Desktop mapping programs allow the user to compare location information with digital base map data. Traditional hand-drawn paper maps can't compete with the speed and flexibility of digital desktop mapping programs. Of course, digital mapping data is needed to do the job, but once data is available, infinite renditions of maps using the same base data is possible.

If a tool described here isn't effective, other tasks are affected. For example, poor recording of observations can still produce a map, but its accuracy is questionable.

The end goal of mapping is to present information about our observations of the world. The better that can be done, the better the goal has been met. When these tools are working together, the cartographic process can be very efficient.

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    Web Mapping
    Web Mapping Illustrated: Using Open Source GIS Toolkits
    ISBN: 0596008651
    EAN: 2147483647
    Year: 2005
    Pages: 138

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