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ChicagoLooper
en respuesta a: Anonymous

First and foremost, you must determine what projection (coordinate system) in the UK you want to use for the final map. In other words, how would you determine the red highlighted 'reference' point or what datum is that x and y referenced to? If you know that point then, of course you can do it, but it would be better with two points, not just one. Two points will account for any rotational effects.  

 

<Let's say I picked a reference point on the drawing, say corner of a building and the local coordinates were x-100/y-100. Then found reference point on the projected coordinates, let's say x-1234/y-1234. Is there a tool in vanilla AutoCad where I could offset the whole drawing, i.e. move whole model on both axis by 1134? >

 

Second, that reference point must be in meters, not latitude and longitude. If it is in lat/long, you'll need to perform an extra step and 'look up' the corresponding x/y values in meters (many free online tools will easily do this).

 

Third, I'm a little rusty (maybe not a little but a lot) when selecting UK datum, so if you set the projection in Global Mapper to British Grid, would you then know what datum to select? There are many. (Alternatively, you can use UTM.)

What datum to choose?What datum to choose?

Your objective now is to determine the location of that building corner in the real world using a known coordinate system. If all you have is a 'local coordinate system' sometimes referred to as a site-specific coordinate system, then you are relegated to simply 'eyeballing' the location of the building and moving your all of your line work manually to the corner (think cut-and-paste).

 

Chicagolooper

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