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1 Replies and 18 Views
ENVIPixelScaleResampleRasterTask 18 1
Started by Marcos Montes
I'm running ENVI 5.5.3 (with IDL 8.7.3). I don't think it matters, but I'm on a MacBook Pro running MacOSX 10.14.6. (I've checked an IDL 8.8/ENVI 5.6 that we have and it appears identical.) I've noticed that through the GUI, using Resize Data, when reducing the number of pixels (i.e., making them cover larger physical space on the ground), there is an option that allows pixel aggregation. However, in what seems to be the most closely related task (ENVIPixelScaleResampleRasterTask), the RES...
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3 Replies and 27 Views
Radiometric Correction 27 3
Started by Jose Manuel Lattus
Hello! Sometimes when i get images with Radiometric Correction Applied, this tool (Radiometric Calibration) allow me to do this correction, so this could be a double radiometric calibration. Anyway sometimes I test applying radiometric calibration and then atmospheric correction, or just applying atmospheric correctiom and the result is the same, for example for AST_L1T, or WorldView2 radiance images. If the image is in level: 'Radiance at Sensor' and I apply a Radiometric Calibration, what ...
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1 Replies and 97 Views
Average NDVI Per Land Cover Class 97 1
Started by Dylan Johnston
Hi! I'm currently working on a project assessing the reduction in NDVI following a hurricane. I've created pre and post hurricane NDVI images, and have also undertaken a supervised land cover classification of the Landsat 8 imagery. I was wondering if anyone knew how I might go about calculating the average NDVI value per land cover class, so that I can quantify the difference. I would truly appreciate some ideas. Thanks!
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1 Replies and 39 Views
ROI with masked pixels but no existing mask 39 1
Started by Federico Carotenuto
I would like to understand better the 'Mask Count' variables under the ROI Statistics tool. I am working with hyperspectral satellite images to which I didn't personally apply any mask. Nevertheless, when I design some ROI and ask ENVI 5.6 (or IDL 8.8 for what matters) to compute the ROI statistics, those are computed only on a subset of the ROI pixels. For example I have a ROI with 11 pixels of which only 1 is used to compute the statistics (and, therefore, no standard deviation) and 10 ...
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0 Replies and 27 Views
ROI with masked pixels but no existing mask 27 0
Started by Federico Carotenuto
I would like to better understand the 'Mask Count' variable in the ROI Statistics tool. I'm working with hyperspectral images to which I personally haven't applied any specific masking. Nevertheless, when I create some ROIs and inspect them with the ROI statistics tool (either in ENVI or IDL) statistics are computed on a subset of the ROI pixels (e.g.: the total number of pixels in the ROI is 11 of which only 1 is used to compute the statistics, and therefore the standard deviation is 0, and ...
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30 Sep 2021 09:52 AM |