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0 Replies and 38 Views NDVI error  38  0 Started by  Mattia Barsanti Using the NDVI algorithm in the toolbox I get an error window: Variable is undefined: . I use a Sentinel-2 (JPEG2000) img with the 4 bands Red (665.0) Green (559.0) Blue (492.3) and NIR (833.0). Data type: Uint Why am I getting this message that does not allow me to calculate NDVI Thanks
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22 Apr 2022 07:14 AM
1 Replies and 59 Views annotations not working  59  1 Started by  Dulci Avouris I'm making some figures and want to export a color bar with my image. I have loaded a greyscale layer and changed the color scheme. When I click on the annotations button the menu is not showing up. This just started today (April 11, 2022). Last week I was able to use the same image for a figure and the annotations worked normally.
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by  Mari MinariJump to last post
14 Apr 2022 10:24 AM
0 Replies and 46 Views Annotations not working ENVI 5.6  46  0 Started by  Dulci Avouris The annotations button is not working in the ENVI 5.6 version that I am currently using. This is a recent options failure. It was working in late March, 2022. Any suggestions I am making figures and need a color bar. Thanks!
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12 Apr 2022 08:45 AM
4 Replies and 117 Views Landsat Collection 2 Level 1 ENVI 5.6.1  117  4 Started by  Jose Manuel Lattus Hello! I'm trying to open a Landsat 9 Collection 2 level 1 in ENVI 5.6.1 and ENVI do not recognize! I try with the MTL.txt file and the xml file I download from earthexplorer site: LC09_L1TP_233079_20220328_20220328_02_T1 please help me! JM Lattus
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by  Jose Manuel LattusJump to last post
31 Mar 2022 06:40 AM
2 Replies and 416 Views ROI with masked pixels but no existing mask  416  2 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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by  Federico CarotenutoJump to last post
25 Feb 2022 10:48 AM
0 Replies and 159 Views AST 09XT Preprocessing Steps  159  0 Started by  Orkun TURGAY Hello forum. I am trying to pre-process 09XT data of ASTER but I think it was different from L1B data processing When I trying to change RPC situation from ENVI header (RPC or RSM) it gives error and wanting to be imported RPC coefficient containing file I am thinking first I have to start orthorectification later then start preprocessing steps but I don't know how to apply orthorectification to the 09XT data do you help me
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30 Jan 2022 08:00 AM
0 Replies and 254 Views Confusion matrix bug  254  0 Started by  Enayat Aria Hi, I have a classification map with three classes. I have also a ground truth dataset provided by ROI tools. The numbers of ground truths (pixels) for classes are 870, 1007, and 695. However, when making the confusion matrix to evaluate the classification, it shows different numbers as the ground truth per class i.e. 598, 887, 695. Just for the third class, it is the same. I do not understand the difference. Why is the total number of pixels of ground truth in the confusion matrix per...
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01 Dec 2021 03:28 AM
1 Replies and 151 Views ISODATA Classification  151  1 Started by  Federico Carotenuto Dear all, I am trying to do some unsupervised classification on hyperspectral images using the ISODATA tool. However, I find some unclarity between the GUI options and the ENVI help. ISODATA requires to specify thresholds about standard deviation of the data ('Maximum class Stdv') and the help states that this standard deviation should be expressed in 'DN' (which I guess means 'Digital Number'). But what does it means exactly I am working on scaled reflectance images, how should I convert...
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by  Mari MinariJump to last post
29 Nov 2021 11:00 AM
3 Replies and 347 Views Seamless mosaicking hanging without errors  347  3 Started by  Federico Carotenuto I'm trying to run a seamless mosaicking procedure on a relatively big dataset (25 images, 186 bands per image, roughly 1400*6100 pixels per image). The procedure starts correctly, the progress bar fills completely, but the process never finishes. Even if the progress bar is completely filled, the GUI still shows 'Exporting results' but the mosaic files seems untouched since many hours from the beginning of the procedure: I've started the mosaic yesterday at roughly 8 PM, now it's 1 PM the day...
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by  Mari MinariJump to last post
29 Nov 2021 07:50 AM
1 Replies and 173 Views Calling FLAASH via IDL  173  1 Started by  Thomas Miraglio Hi, I need to do atmospheric correction on more than 2,000 hyperspectral images, which means batch processing. I would like to use FLAASH, as after testing on several images QUAC and FLAASH led to rather different results. I saw that there is no API specifically designed to call FLAASH, but is it only possible to use it through the GUI or may there be other options Thank you
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by  Mari MinariJump to last post
19 Nov 2021 06:13 AM
15 Replies and 65061 Views Free ENVI 5.3 download  65061  15 Started by  Vy Nguyen I've already created an account to download previous ENVI and IDL versions. But I got message that my access is denied due to verification pending process. So I have to wait up to 24 working hour and later on I can download previous version for free. Please reconfirm if I misunderstood any information! Thank you so much!
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by  Mari MinariJump to last post
28 Oct 2021 08:32 AM
1 Replies and 291 Views ENVIPixelScaleResampleRasterTask  291  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...
1 291
by  Mari MinariJump to last post
22 Oct 2021 06:28 AM
3 Replies and 316 Views Radiometric Correction  316  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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by  Mari MinariJump to last post
21 Oct 2021 10:38 AM
1 Replies and 350 Views Average NDVI Per Land Cover Class  350  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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by  Mari MinariJump to last post
01 Oct 2021 09:57 AM
0 Replies and 183 Views ROI with masked pixels but no existing mask  183  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
0 Replies and 279 Views Calculating total sediment load from Sentinel-3 OL_2_WFR TSM_NN band  279  0 Started by  Nina Eichler Hi, I did try to calculate the sediment load in a coastal region from the Sentinel-3 OL_2_WFR TSM_NN band in SNAP but could not find a way to do it. I was wondering if there might be a (simple) way to do this in ENVI, e.g. by using pixel statistcs This is a task in beginners remote sensing course - so there must be a (relatively) simple way but I can not find any tutorial whatsoever explaining how to do it - is there maybe anyone who could help Any help very much appreciated!
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28 Sep 2021 04:37 PM
0 Replies and 273 Views Dice raster by vector question  273  0 Started by  John Merrill I'm trying to tile out a hyperspectral mosaic using the Dice Raster by Vector function, but I want to use an attribute field from the vector .dbf to name each corresponding tile. I don't see this option anywhere. Does anyone know of a solution
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21 Sep 2021 08:02 AM
4 Replies and 2754 Views input raster must have valid wavelength metadata  2754  4 Started by  xanthi Tseni I have a demo version in Envi 5.5 and i use a module 'crop science' When i import a multispectral image works well but this is not happen when i import pan- sharpened image and try to calculate spectral indices . i takes this messagethat 'input raster must have valid wavelength metadata' How can i fix it The second question is when i import a UAV image from ebee, i have many troubles in pre - processing image ( radiometric and atmospheric correction . Can we help me i appreciate your help ...
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by  Mari MinariJump to last post
21 Sep 2021 07:39 AM
2 Replies and 676 Views Landsat Collection 2  676  2 Started by  Wenjie Ji Hello, I was trying to load the new Landsat Collection 2 data in ENVI using the mtl file (downloaded from but was unsuccessful (ENVI error message 'unable to recognize this file as a standard format'). I did notice that besides the 'normal' bands, Collection 2 also include additional bands such as 'cloud distance', 'upwelling and downwelling radiance'. I didn't have any issue opening Collection 1 data (downloaded from, which has the bands only and the mtl...
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by  Wenjie JiJump to last post
10 Sep 2021 10:23 AM
4 Replies and 363 Views FLAASH Advanced Settings  363  4 Started by  Jose Manuel Lattus Hello! I'm running FLAASH for a Geoeye Image, but I haver negative values in the result. 1. I run with default adavanced Settings 2. Sun Azimuth is 87 in the metadata / Nadir is 18.2 3. I run using Zenith = -93 and Nadir = 180 - 18.2 = 161.8 --> I have negative values always 4. I run using Zenith= -87 and Nadir = 161.8 --> negative values always (anyway higher values than with Zenith -93) any recomendation thanks JM Lattus
4 363
by  Jose Manuel LattusJump to last post
27 Aug 2021 03:29 PM
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