<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>On Feb 18, 2009, at 10:02 PM, Arlindo da Silva wrote:</div><blockquote type="cite">Jennifer, Brian:<div><br></div><div> The new kml option is very cool. Do you have any plans to support PNG with "set gxout kml"? TIFF is proprietary, and have not had a major upgrade since 1992. <span class="Apple-style-span" style="-webkit-text-stroke-width: -1; ">Do you know how well it supports transparency? (Very important for combining layers on GoogleEarth.) You could probably reuse most of the printim code for a PNG option. Just curious.</span></div></blockquote><blockquote type="cite"><div><br>-- <br>Arlindo da Silva<br><a href="mailto:dasilva@alum.mit.edu">dasilva@alum.mit.edu</a><br></div></blockquote><div><br></div>Hi, Arlindo -- <div>I have cc'd gradsusr on this question, since I think it is of general interest. </div><div><br><div>The image files created with 'gxout geotiff' and 'gxout kml' are roughly equivalent to the display inside the plot area of 'gxout grfill' -- a grid of pixels without anything else. So, if you issue the following commands: </div><div>'set parea 0 11 0 8.5' </div><div>'set grid off'</div><div>'set mproj scaled'</div><div>'set x 0.5 720.5'</div><div>'set y 0.5 381.5'</div><div>'set mpdraw off'</div><div>'set grads off'</div><div>'d variable'</div><div>'printim x720 y381' </div><div><br></div><div>Then you would create a PNG that is roughly equivalent to the TIFF and you could substitute that file name in the KML and it would work just as well. In some way, this technique is more flexible because you can use shaded contours, overlay vectors, etc. and still draw them on Google Earth. </div><div><br></div><div>The TIFF file created with 'gxout kml' has the same geolocation metadata embedded in it the way the 'gxout geotiff' output does. The difference is that the 'gxout geotiff' files have floating-point data values for each pixel and the 'gxout kml' files have color-numbered index values. I assume there are some GIS applications that would only need the image and not the data, so that's why I set up a way to create both. The KML provides a handy way to look at the images with Google Earth. </div><div><br></div><div>For testing, I have been using a free program called Quantum GIS (qgis.org). Transparency is pretty easy to control within this application -- you can set any number of pixel values to be transparent (on a scale of 0-100%). I think Google Earth has some controls for transparency too. So far, I haven't seen a need to set up transparency in the GrADS geotiff output. And it's definitely not clear to me that if I put a transparency mask in the TIFF file, the GIS applications will know what to do with it. But I'm still a GIS neophyte... </div><div><br></div><div>Please note that some problems with the 'gxout geotiff' output have been reported to me. I am doing some re-coding and testing and may have some patches and/or an updated version soon. </div><div><br></div><div>Jennifer</div><div><br></div><div>p.s. Hooray for TIFF for keeping the standard consistent for all these years. We need more standards like that. </div><div><br></div><div><br></div><div><div><div><br></div></div><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>--</div><div>Jennifer M. Adams</div><div>IGES/COLA</div><div>4041 Powder Mill Road, Suite 302</div><div>Calverton, MD 20705</div><div><a href="mailto:jma@cola.iges.org">jma@cola.iges.org</a></div><div><br class="khtml-block-placeholder"></div><br class="Apple-interchange-newline"></span></span></div></span> </div><br></div></div></body></html>