[GRASSLIST:4955] Re: Mosaicking and reprojecting

Wayne Thai wayne at keyholecorp.com
Thu Nov 14 20:11:05 EST 2002

So my datum is Nad83, I would need another tool to convert this to Lat/Lon WGS84?
  ----- Original Message ----- 
  From: Richard Greenwood 
  To: Wayne Thai 
  Cc: GRASSLIST at baylor.edu 
  Sent: Thursday, November 14, 2002 4:35 PM
  Subject: Re: [GRASSLIST:4953] Mosaicking and reprojecting

  I am sure other members of this list can answer your question better than I, but usually create an indexed color tiff before importing it onto GRASS. The GIMP does a very nice job of this. If you a bringing in more than one TIFF, be sure you use the same palette for all the images.

  Once you get all your images into GRASS, use the r.patch command to mosaic them together.

  To reproject them, use r.proj. Your state plane coordinate system should be on the same datum as your lat/lon when you use r.proj because while r.proj does a great job of reprojecting, it does not handle datum transformations.


  At 04:15 PM 11/14/2002 -0800, you wrote:

    Hi All,
    I'm a new user to GRASS and I installed it yesterday, and did the tutorial with the spearhead sample data online. Anyhow, now that I have some sort of idea of what I'm doing, I'm running into some trouble. I have a bunch of data, and I would like to make a mosaic of it, then reproject it into LAT/LON. The current projection is State Plane. Here is what I've done so far.
    I have imported the .tif files (with the .tfw) into GRASS, and it separates it into the RGB bands. So what I did was, I used the d.rgb command to display the image, but the colors come out all weird, how do I make it display the real colors. I have also tried using r.in.gdal but when I display that, it comes out black and white. I have also tried r.composite and it also displays weird colors (like a flash back to the 80's with neon colors and all)

  Richard W. Greenwood, PLS
  Greenwood Mapping, Inc.
  Rich at GreenwoodMap.com
  (307) 733-0203
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