Can you check the datum of your WVS data? I don't have WVS.
- Don
On Feb 24, 2012, at 3:59 PM, Tony Vasile wrote:
> Hi Don,
> No what we are seeing is a constant shift of the VMAP data in relation to the DTED data. That is the example point given below is happening across the map. Unfortunately we are using the DTED data for elevation information and if the DTED layer isn't currently displayed if one tries to navigate using the VMAP data one can run aground even though it appears you are in Sydney Harbour because of the discrepancy. Not only do we have a south shift there is also a west shift when both layers are displayed. Our data source for the VMAP data is I believe World Vector Shoreline data. I'm not 100% sure of this. I would have to wait till Monday to find out.
>
>
>
> Tony Vasile
> Senior Software Engineer
> CSC
>
> Level 3B, 26 Talavera Road Macquarie Park NSW 2113 Australia
> GBS | p: +61 2 9034 2404 | f: +61 2 9034 2398 | avasile_at_csc.com | www.csc.com
>
> -----Don Dietrick <dfdietrick_at_gmail.com> wrote: -----
> To: Tony Vasile <avasile_at_csc.com.au>
> From: Don Dietrick <dfdietrick_at_gmail.com>
> Date: 02/25/2012 02:41AM
> Cc: openmap-users_at_bbn.com
> Subject: Re: [OpenMap Users] Openmap displays the VMAP coastline approximately 1.3 minutes of arc to the south of the correct position.
>
> Hi Tony,
>
> The DTED layer in OpenMap doesn't show shoreline - the clear areas on
> the layer are where the elevation is zero. DTED data doesn't know
> anything about shorelines. The edge of the DTED display shouldn't
> exactly match up with the edge of VMAP shoreline features, but I would
> generally expect the DTED to be inside the shoreline features. Is
> that what you are seeing?
>
> Depending on the level of VMAP data (Level 0 is based on 1:1,000,000
> charts) and the level of DTED data (DTED level 0 has posts every 1km,
> DTED level 1 has posts every 100m, or something like that), you won't
> get them to line up perfectly - it's just a matter of the resolution
> of the data and the fact that they aren't trying to show the same
> thing.
>
> For your map display, I would go with your VMAP data and use the DTED
> to augment it by rendering the VMAP land areas with some transparency
> so the elevation shading shows up behind it.
>
> Hope this helps,
>
> Don
>
> On Thu, Feb 23, 2012 at 11:07 PM, Tony Vasile <avasile_at_csc.com.au> wrote:
> > Openmap displays the tip of South Head of Sydney Harbour on the VMAP
> > coastline at 33:51.734S 151:16.672E.
> > On the same Openmap display, the position of the DTED data corresponding to
> > the same point is 33:49.944S 151:16.876E (recognizing that the DTED data is
> > more detailed and so the corresponding points are approximate). This
> > equates to a difference of approximately 1.8 minutes South. An independent
> > check puts the equivalent DTED position at 33:50.102S 151:16.960E which
> > confirms that the DTED position is correct. The VMAP display was then
> > checked using VPFview2.1 which located the same point at 33:50.412S
> > 151:16.665E. This corresponds better with the DTED data and confirms that
> > the source VMAP data is correct.
> > This shows that Openmap is displaying the VMAP data with a displacement of
> > 1.3 minutes South from the DTED data, which is a mix DTED Level 1 and Level
> > 0.
> >
> > We are using OpenMap 4.6.5.
> >
> > Any suggestions on how to get the images to align better?
> >
> > Tony Vasile
> > Senior Software Engineer
> > CSC
> >
> > Level 3B, 26 Talavera Road Macquarie Park NSW 2113 Australia
> > GBS | p: +61 2 9034 2404 | f: +61 2 9034 2398 | avasile_at_csc.com |
> > www.csc.com
> >
> >
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>
>
> Please consider the environment before printing this e-mail.
>
> CSC - This is a private message. If you are not the intended recipient, please delete without copying and kindly advise us by e-mail of the mistake in delivery. Note: Regardless of content, this e-mail shall not operate to bind CSC to any order or other contract unless pursuant to explicit written agreement or government initiative expressly permitting the use of e-mail for such purpose • CSC Australia Pty Limited; Registered Office: 26 Talavera Road, Macquarie Park NSW 2113 Australia; Incorporated in Australia ACN: 008 476 944
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Received on Tue Feb 28 2012 - 00:27:50 EST