GIS Data Capture
Monday, October 20, 2008
A geographic or geographical information system is something which collects data in reference to location. A GIS data capture system such as those we use here does more than simple capture of the raw information as it stores, analyses, manages and presents it too. There are two types of data which can be collected; discrete and continuous and two methods by which both these forms of data can be stored; Raster and Vector. There are pros and cons in using both.Raster:
* requires more storage space
* records data for all points in the area
* is easier to overlay when compared to vector data.
Vector:
* more easy to maintain and update
* addition of new data to old is possible, whereas raster requires entire new image to take into account new information.
* allows queries related to best method of transportation or best route to reach particular target
Data capture from GIS data can be done in a few different ways. Information already present on paper can be digitized into vector format, or scanned into raster data which can actually undergo a further process to be transformed into vector data. In our case we can enter positions from our GPS survey directly into the GIS data capture system. Once the data is inputted it needs to go through a process of editing in order to remove any possible errors caused by overshoot or undershoot, or even dirt which has caused 2 sections to become connected where no connection exists. It is possible, with GIS data capture, to convert the information stored from raster to vector format.
At Anglia Land Surveys we often process information collected by GPS into a GIS data capture system to produce elevations and images useful in the determination of flood risk assessment or a building survey.
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