<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Jonathan,<div class="">The dem_mosaic utility in the NASA Ames Stereo Pipeline suite of tools does exactly what you want. It was developed to efficiently generate large seamless mosaics from 1000s of raster inputs. The user can select from several options for output mosaic values (weighted average, median, first, last, stddev, count, etc.). I recommend that you start with the default weighted average option. Documentation, binaries (Linux and OSX), and source code are available here: <a href="https://ti.arc.nasa.gov/tech/asr/intelligent-robotics/ngt/stereo/" class="">https://ti.arc.nasa.gov/tech/asr/intelligent-robotics/ngt/stereo/</a>. </div><div class="">-David</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class="">---<br class="">David Shean<br class="">Polar Science Center, Applied Physics Lab<br class="">Dept. of Earth and Space Sciences<br class="">University of Washington<br class="">Box 355640<br class="">1013 NE 40th St<br class="">Seattle, WA 98105<br class=""><a href="http://psc.apl.uw.edu/people/post-docs/david-shean/" class="">PSC website</a><br class=""><br class="">Office: (206) 221-8727<br class="">Cell: (301) 801-4558<br class="">Fax: (206) 543-6785</div></div>
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<br class=""><div><blockquote type="cite" class=""><div class="">On Feb 6, 2017, at 2:33 PM, Jonathan Greenberg <<a href="mailto:jgreenberg@unr.edu" class="">jgreenberg@unr.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">GDALers:<div class=""><br class=""></div><div class="">I love the gdalbuildvrt -> gdal_translate trick for large mosaicks, but I have a somewhat more complicated problem I was hoping I could get some help on. Given a large set of overlapping images, I want to mosaic using the following "rules": 1) all overlapping pixels should be averaged together, and 2) any "nodata" pixels in a given input image should be ignored in that calculation.</div><div class=""><br class=""></div><div class="">Is this doable in GDAL? Or am I stuck with just the "top" image in the vrt being the value the output mosaic uses?</div><div class=""><br class=""></div><div class="">--j</div></div><div dir="ltr" class="">-- <br class=""></div><div data-smartmail="gmail_signature" class=""><div dir="ltr" class=""><span class="">-- </span><br class=""><span class="">Jonathan A. Greenberg, PhD</span><br class="">Randall Endowed Professor and Associate Professor of Remote Sensing<br class=""><span class="">Global Environmental Analysis and Remote Sensing (GEARS) Laboratory</span><br class=""><div class="">Natural Resources & Environmental Science</div><div class=""><span style="font-family:"helvetica neue",helvetica,arial,sans-serif" class="">University of Nevada, Reno</span></div><div class="">1664 N Virginia St MS/0186</div><div class="">Reno, NV 89557</div><span class="">Phone: <span id="inbox-gc-number-57" class="inbox-gc-cs-link" title="Call with Google Voice">415-763-5476</span></span><br class=""><a href="http://www.unr.edu/nres" class="">http://www.unr.edu/nres</a><br class=""><span class="">AIM: jgrn307, MSN: <a href="mailto:jgrn307@hotmail.com" class="">jgrn307@hotmail.com</a>, Gchat: jgrn307, Skype: jgrn3007</span><br class=""></div></div>
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