Exporting images at high resolution - NV5 Geospatial

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Last Post 11 Jul 2016 12:13 PM by anon

Exporting images at high resolution

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anon

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11 Jul 2016 12:13 PM
Hi all, I'm wondering if there's a workaround for exporting images from ENVI (or through IDL) at high resolution. I'm working with ENVI 5.3.1. From what I can see, my options for exporting an image from ENVI with all enhancements included (e.g. stretching, sharpening, etc.) are: Export at 72 dpi (Chip view to file; Export view to image file) or Export view to Geospatial PDF and choose the export resolution. Are there any more options than the 2 above? I need at least 300 dpi resolution, and exporting to Geospatial pdf seems to really mute the colors in the image as the file gets compressed. I know that high resolution export is possible through IDL, but I'm working with hundreds of images and manually changing the stretches on each. Ideally, I'd like to be able to make these changes within ENVI and then export the view to a high resolution tiff.

MariM

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11 Jul 2016 02:32 PM
When you use the Export View to image file, you have the option to select the current display extent or the full resolution image. Both options will export the full resolution with annotations and stretches as a byte-scaled 24-bit RGB image). This output has a scale and pixel size but no inherent dpi, which is typically associated with printing to a specific page size. The Geospatial PDF has the option to export a number of pixels per inch but even the fonts aren't in dpi units, but are just the font library symbols that can be rendered at any resolution/size. http://graphicdesign.stackexchange.co...

Deleted User

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11 Jul 2016 04:54 PM
Thank you! That cleared some of my confusion up, but now I'm wondering if I can export with a bit depth larger than 8? The color scaling that takes place during Export View (from Landsat's 12 bits to 8 bits) really changes the look of the image.

MariM

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12 Jul 2016 07:08 AM
If you want to retain the stretch and annotations 'burned' into the image, then you are exporting how it looks in the display which is 8-bit (byte-scaled between 0-255). It only exports an RGB image (3 bands). You can save the image in the original data type and include all bands but it won't retain the stretch or annotations. This is done using File->Save As. If you are using a default stretch, there is an option in the image header where you can set a default stretch to use when you open the file in ENVI.

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