Definitely a great thread.
I would think that regardless of whether you use internal datums or
WGS84, you also want to work out a mapping of the coordinate system to
place names. Much like the fuzzy neighborhood naming activities.
"Third shelf from the top in my office." "Red box in the attic that
we used to keep ornaments in. "
And that leads to the issue of containers that move. If each container
had an ultra-local datum, you could deal with where something is
inside a container, even as you allow the container to move. Then you
only have to update one item, rather than a zillion. Realizing that a
container could, in fact, be a photo album. "Bottom right photo on
page 15 in the wedding album."
I was just thinking this morning that some form of do-it-yourself RFID
dust system would be useful. Could I just buy a box of tags, slap them
onto things I care about, then read the tag, note what it's attached
to, and let things drift around the house, as they are wont to do?
Later, do some kind of a sweep with a wand and know where things are.
Nirvana ensues.
Of course then I'd want tags that only work inside my house, or that
are only readable by my wand...
On Feb 1, 2008, at 1:44 AM, Alan Keown wrote:
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 <[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
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--
Will King
0044 (0) 77950 96645
http://geodatasolutions.co.uk
GPS Surveying | Location Data Capture | GIS Digital Mapping
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