[Manifold-l] Surfer .GRD import

[Pat Waggaman]

Are the data in Lat Long?  What units & what 
projection is incoming data and output data?

Does the squishing appear when you project in Manifold to Lat Long?

You´re getting data which is presumably gathered 
at a constant distance interval, that, when 
translated to Lat Long, causes the apparent squishing.

Pat

At 12:37 03-05-2007, M Roseveare wrote:
>Thanks Pat,
>
>The problem occurs though in orthographic projection - long and lat don't
>come into it unfortunately! The data starts off as orthographic and remains
>so and hence no distortion should happen. The actual squishing seems to
>relate to the ratio of the resolutions in the grid. However, changing scale
>factors etc has no affect.
>
>
>
>
>Martin Roseveare
>Senior Geophysicist
>
>
>Web: www.archaeophysica.co.uk
>Phone: +44 (0) 1989 730 564
>Fax: +44 (0) 7050 369 790
>
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>-----Original Message-----
>From: Pat Waggaman [mailto:waggaman at marimsys.com]
>Sent: 03 May 2007 17:27
>To: m.roseveare at archaeophysica.co.uk; manifold-l at directionsmedia.net
>Subject: Re: [Manifold-l] Surfer .GRD import
>
>In bathymetry, back when we were doing a lot of it - we needed the
>same Surfer to Manifold integration.
>
>Our workaround - and this is several Manifold versions ago - was to
>export CSV from Surfer and then import those tables into Manifold.
>
>East - West "squishing will occur with the cos(Lat) x 60 nm of
>"Longitude compression" as you near the poles.  If that is a problem,
>raise it as a separate issue, there are questions here of the source
>data projection and what you want as a finished product.
>
>Cheers,
>
>Pat
>
>
>
>At 11:24 03-05-2007, M Roseveare wrote:
> >Hi all,
> >
> >Has anyone come up with a work-around for the Manifold's seemingly dodgy
> >import of Surfer grids (as surfaces)? I say dodgy because Manifold always
> >squashes the grid in the east - west direction. I've tried changing various
> >combinations of scale factors but none yield the correct result. It used to
> >be the case that ASCII format grids did this but Surfer 7 binary didn't, in
> >the latest version of Manifold they all come out wrong...
> >
> >Any advice welcome - I suspect that it's a bug but wondered whether anyone
> >else has observed the same thing?
> >
> >Thanks.
> >
> >
> >
> >Martin Roseveare
> >Senior Geophysicist
> >
> >
> >Web: www.archaeophysica.co.uk
> >Phone: +44 (0) 1989 730 564
> >Fax: +44 (0) 7050 369 790
> >
> >This e-mail and any attachment may contain proprietary or confidential
> >material and be subject to legal privilege. If you have received it in
>error
> >please promptly erase it from your system and inform the sender.
> >It should not be copied, disclosed to, retained or used in any way by any
> >other party.
> >
> >Nothing in this e-mail should be regarded as representing a binding
>contract
> >unless explicitly stated otherwise. All opinions are those of the sender
>and
> >not necessarily ArchaeoPhysica Ltd.
> >
> >
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