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The USGS orthoimage is a 6 inch resolution quadrangle that is loaded into GeoServer as a WorldImage. GeoServer has an extremely hard time processing this compared with a 1 foot resolution quadrangle. How can this orthoimage be edited?

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Do you perhaps know what software you have at your disposal for accomplishing this? –  Chad Cooper Jan 6 '12 at 21:31
    
No. I could use suggestions for software to use. –  Matt Jan 6 '12 at 21:47
    
OK, I know nothing about GeoServer, but I had to look up WorldImage, and it looks like as far as GeoServer is concerned, it's just a raster image with a world file. So do you have a raster image as well, say a tiff maybe? Or am I totally wrong on this? –  Chad Cooper Jan 6 '12 at 22:26
    
Yes, a TIFF with a world file. –  Matt Jan 9 '12 at 13:44
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2 Answers 2

up vote 3 down vote accepted

Sounds like you want to resample your data. gdalwarp, part of the GDAL suite of tools, can do this for you, and it's free and easy to use. I went and found some 6-inch aerials, and resampled one from 6 inch to one foot resolution in both the X and Y:

C:\Temp>gdalwarp -tr 1.0 1.0 Adona_1.tif Adona_1-2.tif

This took the 6 inch resolution tiff of about 88MB down to about 22MB. I loaded them into QGIS, another free tool for you to use, and here is how they compare:

enter image description here

Not too shabby, actually.

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This answers my question, although I think converting to a tiled GeoTiff will be the GeoServer optimization that I am ultimately looking for. –  Matt Jan 10 '12 at 14:09
    
Would you know the correct way to convert that the GeoTiff using gdalwarp or gdal_translate? gis.stackexchange.com/q/18667/3119 –  Matt Jan 10 '12 at 16:41
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World image is not a suitable format for web serving, use something like GeoTiff. With GeoTiffs you can create overviews which are exactly what you want, lower resolution versions of the image that geoserver will load at higher scales.

There is some good info in the user guide for this.

http://docs.geoserver.org/stable/en/user/production/data.html#pick-the-best-performing-coverage-formats

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The only reason I am using WorldImage is because that is the format the USGS Earth Explorer provides for Orthoimage quadrangles. I do not know of a better option for displaying items a meter apart on a map (some blurriness is fine, obviously). –  Matt Jan 6 '12 at 21:52
    
Yeah, it is a common format, but just not one suited to serving maps since (depending ont the format) generally it won't support tiled access (only loading sections of the image that we need), and overviews (loading lower resolution versions of the image). The consequence is that for every map request geoserver has to load the entire image from the disk, leading to poor performance. –  jdeolive Jan 7 '12 at 2:09
    
I think converting to GeoTiff is the ultimate answer that I am looking for, however GeoServer 2.1.2 is throwing an exception on "doSave" each time I try to save a converted GeoTiff. –  Matt Jan 10 '12 at 13:23
    
Related question here: gis.stackexchange.com/questions/18667/… –  Matt Jan 10 '12 at 14:29
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