I've done some preliminary research, looking up definitions for these terms, but I would like an explanation of what the application of a Control Point or Monument is for the average GIS?

I am still new to the field of GIS.


In layman's terms, using known locations/monuments in order to georectify your map/image.

Georectify: To take an image that has not been adjusted to be in a known coordinate system, and put it into a known coordinate system.

  • So, you might have a monument on a street corner in different parts of the city, then you can use those known points to line up an aerial image or something? – Nomkins Nov 4 '14 at 20:31
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    exactly, and then discern a coordinate system from distance measurements – Maksim Nov 4 '14 at 20:32
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    @Nomkins This doesn't just apply to image/raster data, but vector as well. Simply speaking, control points and monuments are simply "known" points that can be used to align, correct, or reference data from different sources. They can have more specific and detailed functions depending on the specific topic area - such as in parcel fabrics and survey networks. – Chris W Nov 4 '14 at 20:38
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    In the city I previously worked in, monuments were typically iron rods with very precise known locations in the coordinate system we used. Developers platting subdivisions were required to calculate a tie (length and bearing) to at least one monument in order to more precisely place the platted parcels(s), and to check for any discrepancies with existing data. – recurvata Nov 4 '14 at 21:20

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