[Xastir-Dev] problem with drg geotiff maps

[J. Lance Cotton]

Curt,

I don't think what I have are MrSID compressed files. They have the .tif 
extension and I can `xview` them with the following output from xview:

[jlc7944 at baconcheddar geotiff]$ xview 309621o.tif
309621o.tif: Warning, unknown field with tag 33550 (0x830e) ignored.
309621o.tif: Warning, unknown field with tag 33922 (0x8482) ignored.
309621o.tif: Warning, unknown field with tag 34735 (0x87af) ignored.
309621o.tif: Warning, unknown field with tag 34737 (0x87b1) ignored.
309621o.tif is a 5042x5796 8-bit single-plane colormap Macintosh TIFF 
imageTitled "single-plane "
Using DirectColor visual
Building XImage...done

ImageMagick can read it just fine. I do have some other files in MrSID 
format, but they're areal photographs and I know ImageMagick won't read it.

However, I will re-install my MrSID tools and see if I can do anything 
with that... I'll keep you guys up on my progress.

73 KJ5O


Curt Mills, WE7U wrote:

> On Wed, 30 Oct 2002, J. Lance Cotton wrote:
>
>
> >Yes, Sorry. Still doesn't draw the DRGE.
>
>
> Just figured out that they use a proprietary compression format
> called MrSid for the DRG-E files.
>
> Here's a blurb from a MicroDEM web page that talks about them.
> Looks like you might be able to convert them to standard geoTIFF
> files:
>
>
> "See: http://wgiac.state.wy.us/wsdc/usgs/drg/AboutDRG.html for topo
> maps in DRG format.
>
> See: http://wgiac.state.wy.us/wsdc/drg-e/index.html for the topo
> maps in DRG-E format. You can download the quads at 1:24,000 scales
> in MrSid (DRG-E) or GeoTiff (DRG) format. Save the DRG-Es in Geotiff
> format using the MrSid viewer.  Check metadata and note that the
> coordinates are in UTM on the NAD27."
>
>
> You might give it a try and see if it works.  If so, I'll add some
> stuff to the README.1ST file about this map format.
>
> Be careful of the NAD27/NAD83 difference.  It's possible that the
> converted files might be off by a datum shift when used with Xastir.
>

-- 
J. Lance Cotton, KJ5O
Apple decided to charge money for my mac.com address so: 
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