comp.lang.idl-pvwave archive: archive » Reprojecting an image file derived from Level 1B MODIS HDF

Home » Public Forums » archive » Reprojecting an image file derived from Level 1B MODIS HDF

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Reprojecting an image file derived from Level 1B MODIS HDF [message #74292 is a reply to message #74228]

Thu, 06 January 2011 17:51

devin.white
Messages: 50
Registered: March 2007

Member

The reason for the misalignment could be geopositioning errors in the
Longitude and Latitude bands, but an equally likely situation is that
the native imagery in Google Earth is not in the right place. That
happens a lot. You should by no means treat the imagery in Google
Earth as truth. It's generally good to about 30m, but not always.
Google Earth's native projection space is Geodetic (longitude and
latitude with respect to the WGS-84 ellipsoid). I think it supports
UTM and a few other projections, but Geodetic is the safest to use.

On Jan 5, 7:22 pm, Kasia <sia...@gmail.com> wrote:
> Wow! Thanks for all these replies. I have the tools to reproject the
> original file now but that would then require modifying the code that
> generates the jpeg, which I don't have, unfortunately.
>
> Devin, I discovered the ENVI Build GLT command after I posted this and
> it has been working great in reprojecting the jpeg. BUT the images
> don't line up with the landscape after displaying in Google Earth.
> I've triple checked the lat/lon box coordinates that I wrote into the
> kml and they seem to be correct so the only thing I can think of is
> I'm using the wrong projection.
>
> So the next question is...What projection does GE want? I've heard the
> following:
> Mercator
> Equirectangular
> World Equidistant Cylindrical (Sphere)
>
> Which one is it? I did this over a year ago successfully with
> different datasets using GDAL and the World Equidistant Cylindrical
> (Sphere) projection, but I also remember reprojecting another MODIS
> dataset using ENVI and Equidistant Cylindrical is not an option in
> ENVI.
>
> There are plenty of other options, so any suggestions?
>
> Thanks again!
> Kasia

Report message to a moderator

[Message index]

		Reprojecting an image file derived from Level 1B MODIS HDF By: Kasia on Sun, 02 January 2011 15:23
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: Kasia on Wed, 05 January 2011 16:22
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: devin.white on Thu, 06 January 2011 17:51
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: David Fanning on Wed, 05 January 2011 09:37
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: Michael Galloy on Wed, 05 January 2011 09:25
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: David Fanning on Wed, 05 January 2011 06:03
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: devin.white on Wed, 05 January 2011 05:27
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: David Fanning on Tue, 04 January 2011 20:10
		Re: Reprojecting an image file derived from Level 1B MODIS HDF By: devin.white on Tue, 04 January 2011 19:47

Previous Topic:	Read large ascii file quickly
Next Topic:	IDL 8, EPS vs. PS graphics

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 19:42:05 PDT 2025

Total time taken to generate the page: 3.91996 seconds