Mike, I've been following this thread all day - I think the whole thing sounds like a lot of fun.
As far as I know there is no "mathematical or programmatic reason" why this can't be done as you suggest; but it is complicated. Each of your internal control points becomes a local Coordinate Reference System datum. Once you calculate the offset, from that point, to your standard geodetic Coordinate Reference System you can apply a transformation to all the other local points. This would need to be done for each control point (ie each room on each floor in the building). Theoretically this will work - the practical reality (speaking as someone - yes another surveyor - who spent many years measuring internals of buildings for Title Deed plans) is that wall shifts and floor shifts make it a real pain to determine the offset from the internal control points to the external with any real degree of accuracy. On the other hand, taking off the surveyor's hat, Sydney City Council has completed a "Floorspace & Employement Survey" of all commercial space in its jurisdiction. The used, I believe, Distos and architectural plans and now have a weird looking 3D model of the insides of most of the city's buildings referenced to the Map Grid of Australia CRS. The city is now in the process of developing a 3D model of the outside of the buildings - many people are waiting to see if the insides fit. Cheers AlanK _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Liebhold Sent: Friday, 1 February 2008 4:17 PM To: [email protected] Subject: Re: [Geowanking] Converting Lat Long to X Y Will King wrote: " The "local" coordinates for this light switch would then be (x)10.000, (y)5.000, (z)2.000. seems like the right way to internally map a mobile object, but wouldn't it make more sense to describe a - place - [ indoor room] in a common geodetic standard coordinate system? is there a mathematical or programmatic reason why not? First measure the lengths of your walls with tape or disto. Lets say your room is 10 metres by 5 metres. Then divide this into theoretical grid squares of your choosing ie 1 metre squares. By the way, this looks like great fun. i'm bringing my carpenter's laser level to wherecamp. to use , unless someone brings some pro indoor surveying gear to help map [ and render? and geotag?] an indoor space, in detail. now i'm wondering what's the cheapest, most accurate short -distance range finding hack. - something like a very low power lidar for rendering indoor terrain. Pick a corner and call this 0.000, 0.000 (this is your bottom left of your living room "grid" if you drew it on paper). Diagonally across (ie top right corner) from this coordinate is 10.000, 5.000. You can then get any coordinate in the room from this grid. To get a z level (elevation) measure up from your floor and "set a level" one metre or whatever up, mark it with pencil etc. Will On Jan 31, 2008 10:24 PM, Mike Liebhold <[EMAIL PROTECTED]> wrote: I'm thinking of mapping my living room. Does anyone have any sugggestions How should I convert the location of furniture, lamps, into location coordinates? I think I know how to do x and y, but z is a problem, though highly useful for finding things like books. - mike John Handelaar wrote: On Jan 31, 2008 9:34 PM, Paul Harwood <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]> wrote: Hi, Just a lazy question from a novice geowanker I suppose...but it might save me an evenings surfing though if you can help. I have googled a bit, with a few solutions... but does anyone have a perl script (or a site) to hand, to do Lat Long conversions to X Y? I have UK postcode/outcode/location database that I want to convert from L Lo to X Y. Again, "X Y" doesn't seem to mean anything specific, but a number of useful tools and code samples, including stuff relating to OSGB grid refs, can be found here: http://www.nearby.org.uk/downloads.html _______________________________________________ Geowanking mailing list [email protected] http://lists.burri.to/mailman/listinfo/geowanking _______________________________________________ Geowanking mailing list [email protected] http://lists.burri.to/mailman/listinfo/geowanking -- Will King 0044 (0) 77950 96645 http://geodatasolutions.co.uk GPS Surveying | Location Data Capture | GIS Digital Mapping _____ _______________________________________________ Geowanking mailing list [email protected] http://lists.burri.to/mailman/listinfo/geowanking
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