Re: Address -> coords

Hi Don,

mmmm... A few references I've found agree with this:

> The ideal solution to all of the above problems would be a spheroidal
> model that has both the correct equatorial and polar radii, and is then
> centered on the actual center of the Earth. One would then have a
> spheroid, that when used as a datum, would accurately map the entire
> Earth. All lat/longs on all maps would agree. That spheroid, derived
> from satellite measurements of the Earth, is GRS80, and the datums that
> match it are NAD83 and WGS84.

Wouldn't this mean that NAD83 and WGS84 should match?

        --G

On Fri, Oct 12, 2001 at 11:24:13AM -0400, Donald Dietrick wrote:
> I checked out some my my esri street data (I think that was TIGER data)
> versus VMAP level 0 data, and found that they are off, too. I went to
> the US Census TIGER site, and they do say that TIGER data is in the
> NAD83 datum, as opposed to the WGS84 datum of OpenMap projections and of
> the other data sources used. That explains the offset - it's the TIGER
> data.
>
> So, to get the maps to match, something needs to go through coordinate
> translation.
>
> - Don
>
> On Thursday, October 11, 2001, at 02:16 AM, Guillermo Payet wrote:
>
> >
> > Hi Don,
> >
> > This is what I mean:
> >
> > http://dev.wifinder.com/search.jsp?map=map&scale=0.9012346&lat=37.74302&lon=
> > -122.34541&loc=&add=&x=131&y=81
> >
> > The streets come from TIGER data, and the land forms come from the
> > NationalAtlas site.
> >
> > --G
> >
> >
> > On Wed, Oct 10, 2001 at 03:30:32PM -0400, Donald Dietrick wrote:
> >> Hi G,
> >>
> >> On Monday, October 8, 2001, at 02:56 PM, Guillermo Payet wrote:
> >>
> >>>
> >>> Hi Don,
> >>>
> >>> We're looking at the service from www.geocode.com for this. If their
> >>> price is right, then we'll use them. Otherwise I'll be writing the
> >>> software.
> >>>
> >>> Also: I'm noticing that the state boundary shapefile data from
> >>> nationalatlas.gov and the street data from the census bureau
> >>> (shapefile
> >>> conversions downloaded from ESRI) don't match. That is... coastlines
> >>> and streets are offset by quite a bit, and a lot of streets show in
> >>> the middle of the ocean. Strange.. What's the deal? Which one is
> >>> wrong?
> >>
> >> It's probably not that one of them is wrong, just that they don't match
> >> each other. I bet they have different datums if the error is constant
> >> with respect to direction. If the differences are more random, than it
> >> could be that you've exceeded the accuracy of the state boundary maps
> >> (that depends on what the source for them is).
> >>
> >> - Don
> >>
> >>>
> >>> --G
> >>>
> >>>
> >>>
> >>>
> >>> On Mon, Oct 08, 2001 at 10:23:46AM -0400, Donald Dietrick wrote:
> >>>> Hi G,
> >>>>
> >>>> Several people have asked about it recently, but nothing has been
> >>>> submitted to BBN. This would definitely be something that we would
> >>>> love
> >>>> as a contribution, and would include it in the package if submitted.
> >>>>
> >>>> - Don
> >>>>
> >>>
> >>> --
> >>> [To unsubscribe to this list send an email to "majdart@bbn.com"
> >>> with the following text in the BODY of the message "unsubscribe
> >>> openmap-users"]
> >>>
> >>>
> >
> >
> >
> > --
> > Guillermo Payet
> > O C E A N G R O U P
> > President/Chief Technology Officer
> > email: gpayet@oceangroup.com
> > web: http://www.oceangroup.com
> > public key: http://www.technosterone.com/crypto
> > U s e d a t a E N C R Y P T I O N ! ! ! !
> >
> >

-- 
Guillermo Payet
O C E A N    G R O U P
President/Chief Technology Officer
email: gpayet@oceangroup.com
web: http://www.oceangroup.com
public key:  http://www.technosterone.com/crypto
U s e    d a t a    E N C R Y P T I O N ! ! ! !
--
[To unsubscribe to this list send an email to "majdart@bbn.com"
with the following text in the BODY of the message "unsubscribe openmap-users"]