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1 Replies and 1446 Views Best method for vegetation analysis  1446  1 Started by  Deleted User I'm probably asking a question that requires a research project, but has anyone found a method to extract species of plants using a spectral library
1 1446
27 Apr 2015 02:58 PM
3 Replies and 1640 Views decorrelation stretch, is there a reference?  1640  3 Started by  Deleted User I could not find any clear explanation on what ENVI does during the decorrelation stretch. There is only the following information online: Tip: You can obtain similar results to decorrelation by using a sequence of forward principal components (PC), contrast stretching, and inverse PC transforms. Is there any reference describing the actual implementation
3 1640
24 Apr 2015 07:52 AM
1 Replies and 1616 Views calculate co-relation  1616  1 Started by  Deleted User how to calculate co-relation in envi.
1 1616
24 Apr 2015 04:16 AM
1 Replies and 1273 Views as squaring in math band ????  1273  1 Started by  Deleted User as squaring in math band
1 1273
21 Apr 2015 04:29 PM
2 Replies and 1645 Views SAM/MF classification  1645  2 Started by  Deleted User Can Spectral Angle Mapper or Matched Filtering classification be performed without doing Pixel Purity Index If not why If yes how
2 1645
20 Apr 2015 02:34 AM
1 Replies and 1321 Views layerstacking  1321  1 Started by  Deleted User I am trying to layerstack several landsat 8 bands (all of which are mosaicked landsat bands). Each band is projected the same (UTM WGS84 21N) and I choose the layerstck parameters to match. However, the result repeatedly comes out to be zone 21S. I am trying to preserve data values, so reprojecting back into zone 21N is not a good option. I cannot determine why it would be changing, nor why choosing the correct zone will not assure the result will be projected accurately. I have tried ENVI and t...
1 1321
17 Apr 2015 09:17 PM
1 Replies and 1508 Views How to edit class names and colors  1508  1 Started by  MariM After I create a classification image through the'Classification Workflow', the default simply names the classes as Class 1,Class 2, etc., and assigns them default colors. I need to change the names and colors of these classes, so I right-click on the classified image in the "Layer Manager" and click on 'Statistics for all classes...' It brings up the 'Classification Statistics View' dialog box, in the 'Curve' tab. I can change the name and color, but it has no effect on changing the ...
1 1508
17 Apr 2015 01:38 PM
3 Replies and 1658 Views Mosaic Landsat 8  1658  3 Started by  Deleted User I would like to mosaic two surface reflectance scenes, but preserve the reflectance values in the mosaic. I have use the seamless mosaic tool with settings I thought would accomplish this, but each time the resulting reflectance values are far too low.
3 1658
17 Apr 2015 08:02 AM
1 Replies and 1350 Views help getting decision tree expression right  1350  1 Started by  Deleted User In ENVI 5.2, I am trying to run a decision tree on NDVI image derived from Landsat 8 satellite data, but I am not getting proper results. I want to classify the NDVI values which are greater than(>)0.3 as crop lands and lesser then(< )0.3 as non-crop lands. I tried with the expression. {ndvi} GE 0.3 But its giving result as non agri(ppt attached). Please guide me how to write a correct expression. I will look forward for your reply.
1 1350
16 Apr 2015 08:36 AM
1 Replies and 1548 Views hyperion data correction  1548  1 Started by  Deleted User how to correction flag mask and smile affect 'frown' curve.
1 1548
15 Apr 2015 02:29 AM
1 Replies and 1639 Views IMAGE NOISE & DIMENSIONALITY  1639  1 Started by  Deleted User How I estimate image noise of a Hyperion L1R data. I wants to know about Signal to Noise ratio. please help me.
1 1639
15 Apr 2015 02:10 AM
15 Replies and 1899 Views NDVI per altitudinal range  1899  15 Started by  Deleted User Good Morning, I have 5 landsat images (different dates) and a SRTM DEM of my study area. For each image I would like to calculate the mean NDVI per altitudinal range. The altitudinal ranges are the following : 0-3000 m; 3000 - 4000m; 4000-5000m and over 5000m. Should I create different masks per altitudinal range using my SRTM DEM and then clip each images and then run the NDVIs What would be the best method and tools with ENVI My images are already geometrically and atmospherically corrected....
15 1899
14 Apr 2015 11:42 AM
1 Replies and 1797 Views AUX files ?  1797  1 Started by  Deleted User Why doens't ENVI 5.1 produced .aux files when I save the imagery to ERDAS native files so ArcGIS or ERDAS can read it
1 1797
14 Apr 2015 08:02 AM
1 Replies and 1502 Views Linear Spectral Unmixing with Aster VNIR  1502  1 Started by  Deleted User Hello ! I am having troubles with understanding the results of my unconstrained Linear Spectral Unmixing application in ENVI. The pixels in my resulting fraction images gives me data that ranges from -3 to 9. Can I still use this data even though they are very much outside the 0 to 1 range What can I do to improve my unmixing Also, is it normal that a single value (0.15....) was attributed to all of the background that I had defined with a mask Here is some more detailed information : I ...
1 1502
09 Apr 2015 01:16 PM
7 Replies and 1404 Views TIF to  1404  7 Started by  Deleted User So, whenever I stacked the bands and save them in TIF file..it looks like ERDAS 2013 I have on my computer does not like to open it. Is there a way around to fix it or is it that I need to upgrade to ERDAS 2014 they are having a problem with the ERDAS 2013
7 1404
08 Apr 2015 08:55 AM
1 Replies and 1666 Views Can I call Radiometric Calibration tool using ArcGIS 10.3?  1666  1 Started by  Deleted User Can I call ENVI's Radiometric Calibration tool using ArcGIS 10.3 If yes - how to do that Can't find this tool in ArcGIS's toolbox called "ENVI Tools".
1 1666
08 Apr 2015 04:19 AM
2 Replies and 1610 Views Remove a band from an imagery  1610  2 Started by  Deleted User What tool do you use when you remove a band from a multispectial, for example,, when you stack a few bands and realized you don't need a band.... Thanks, Robert
2 1610
07 Apr 2015 12:37 PM
2 Replies and 1531 Views Metadata Viewer Question  1531  2 Started by  Deleted User Hello all, Currently I am using ENVI 5.1 I upgrade from 5.0 a few months ago back..now I am starting to work on ENVI again,.. Now I have a question how to export the spectral attribute of the wavelength when you open text in ENVI. It shows all the spectral information in the Metadata Viewer. The Metadata Viewer has the button "export"l that you can save it. I would like to hear your input on that if there a way around for me to add it when I stacked the bands Adios !
2 1531
02 Apr 2015 05:11 PM
1 Replies and 1685 Views Spectral Angle Mapper for multiple classes  1685  1 Started by  Deleted User What does spectral angle mapper do when a test spectra matches more than one reference spectra Does SAM give priority to one reference spectra over an other based on how the library is built i.e. if the test spectra matches two reference spectra, and one is listed first in the library, does SAM give priority to the reference spectra listed first How would SAM resolve if a test spectra falls within the angle cut-off of two reference spectra
1 1685
01 Apr 2015 10:15 AM
1 Replies and 1958 Views extinction coefficient and visibility  1958  1 Started by  Deleted User Where does the equation relating the extinction coefficient to visibility shown in the FLAASH tutorial at https://www.exelisvis.com/portals/0/pdfs/envi/Flaash_Module.pdf come from I am referring to the equation: V=3.912/ ß
1 1958
30 Mar 2015 12:55 PM
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