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2 Replies and 1000 Views
NDVI color mapping 1000 2
Started by Deleted User
Hello Friends,
I have created NDVI image from TM data in Envi 4.5. When I display image it appears in gray scale (ie. black to white scale). I have used Tool>color mapping>envi colorr table options and selected blue to red option to see the no biomass feature in blue to high biomass feature in red.
My questions are-
1) Is it possible to convert this continous scale information into different classes(based on interval).
For example, If I do density slicing it gives an option to sa...
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2 |
1000 |
15 Sep 2010 02:48 AM |
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1 Replies and 1317 Views
FLAASH LANDSAT5 TM - strange values bands 5 & 7 1317 1
Started by Deleted User
Hi ENVI user community,
I hope somebody can help me identify what I’m doing wrong with FLAASH.
I’m using 4.4 (so that’s probably the start of the problem right )
I’ve been following the steps outlined in the tutorial
http://www.ittvis.com/portals/0/tutorials/envi/FLAASH_Multispectral.pdf
The results seem especially strange in bands 5 & 7, making me think that the entire operation is suspect. Below I’ve outlined what is going on, and the pr...
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1 |
1317 |
14 Sep 2010 09:34 PM |
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1 Replies and 1141 Views
How to process LANDSAT-7 band images using ENVI? 1141 1
Started by Deleted User
Hi,
I am new to ENVI and I would like to process the Standard Terrain Correction (Level 1T) LANDSAT band images downloaded from GLOVIS webpage.
My intention is
(1) to process the images with atmospheric correction and obtain obtain radiance or TOA reflectance ASCII file.
(2) to transform the band images to compute NDVI
Is it possible to achieve my goals using ENVI If so, please suggest me in step wise procedure in achieving my goals. I would be greatful for your help.
...
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1 |
1141 |
13 Sep 2010 10:57 AM |
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1 Replies and 1057 Views
ROI from shape file 1057 1
Started by Deleted User
Few days back I selected a Region of Interest in ENVI and saved (Export to Shape file) as shape file.
Now I want the same ROI to be used to subset the data without redrawing the ROI.
Is it possible to overlay the shapefile and treat it as ROI polygon and subset the data
If yes, How
Please help
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1 |
1057 |
12 Sep 2010 10:52 PM |
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1 Replies and 1403 Views
Textural analysis - Co-occurrence shift value 1403 1
Started by Deleted User
Hello
I am trying to compute some textural features using the co-occurrence filter. What values should I use in the “co-occurrence shift Y” to calculate the 0º, the 45º, the 90º and the 135º directions. I know that “shift Y=0” is the 0º angle, but I am confused with the other values.
I want to use a neighbourhood of 1(shift X=1) for a processing window of 3x3.
Thank you
Rosário
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1 |
1403 |
10 Sep 2010 08:09 AM |
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3 Replies and 1278 Views
Lost projection in processing SPOT4 in FLAASH 1278 3
Started by Deleted User
Hi all,
I have SPOT 4 image in CAP format and "Pseudo Geographic Lat/Lon" projection, after atmospheric correction in FLAASH, it lost the projection, though I tried to registed it with the original SPOT4 image, the warp image still does not have projection.
I wonder to know whether it affects the result if I convert the projection to a commonly used one before processing. Or anyone could give a better solution
Thanks!
Rong
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3 |
1278 |
09 Sep 2010 09:00 PM |
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0 Replies and 985 Views
Compute the new value of latitude 985 0
Started by Deleted User
Hello,
Does anyone knows how are computed the new values of latitude and longitude if a rotation has been performed The header of the rotated image is the same as the header of the original image, only the rotation information appear.
Is it used a simple 2D rotation matrix
Thanks,
drosu
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0 |
985 |
09 Sep 2010 03:43 AM |
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1 Replies and 1115 Views
Imagine files still unsupported 1115 1
Started by Deleted User
Why are imagine files still not opening in ENVI 4.7SP2 ITT is advertising that they are finally getting it together. NO matter what i do they aren't coming in. Please advise, I have 259 files that i need to bring in an process. Also, I have ARCGIS desktop etc license but the IDL envi_open_external_data for /ARCGRID also does not function. -ska1
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1 |
1115 |
03 Sep 2010 06:08 PM |
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2 Replies and 1141 Views
Add Personal Band 1141 2
Started by Deleted User
Hi, I have to add a "personal band" to a L2 Meris Image.
that's it,I open an L2 Meris Image, then I export a band subset, I work with this subset, then I have to import the result into the L2 Image like a new band.
How can I do
Thanks, Gaetano.
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2 |
1141 |
02 Sep 2010 12:06 PM |
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0 Replies and 1107 Views
Warped Output image 1107 0
Started by Deleted User
I’ve encountered what has been an ENVI/IDL conundrum for me. I wrote some IDL code to compute fractional values for a class; each fractional value is based on the number of high resolution pixels existing within a coarse resolution pixel. I’m using images with a North EASE projection (NSIDC).
Here’s my routine. I have one image that is a 300 m classification map. I have one image that is 25 km. I clip the 25 km image so that the dimensions are the same as the 300 m ma...
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0 |
1107 |
02 Sep 2010 08:06 AM |
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4 |
1442 |
02 Sep 2010 03:28 AM |
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1 Replies and 1100 Views
map cooridnate convert error 1100 1
Started by Deleted User
Map coordinate convert error in ENVI 4.7 prompt me
"Reprojection error Coordinate system is not set "
while in ENVI 4.2 is OK
I define a new datum "beijing-54 krassovsky ******" in datum.txt
a new projection in map_proj.txt
the define is the same in ENVI 4.7 and 4.2
I am puzzled
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1 |
1100 |
31 Aug 2010 07:31 PM |
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2 Replies and 1107 Views
ROI reconcile to map (scaling) 1107 2
Started by Deleted User
When I reconcile an ROI via map (between two georeferenced images of *differing pixel size), the reconciled ROI looks like....gridded dots. For example, I start with an image that is ~200m/pix and reconcile an ROI from that image to one that is ~100m/pix. It seems like it won't extrapolate the ~200m/pix ROI and fill in multiple pixels in the 100m/pix image. Is there a way of doing this
Thanks for your time!
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2 |
1107 |
25 Aug 2010 10:15 AM |
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0 Replies and 1144 Views
ROI reconcile to map (scaling) 1144 0
Started by Deleted User
When I reconcile an ROI via map (between two georeferenced images of *differing pixel size), the reconciled ROI looks like....gridded dots. For example, I start with an image that is ~200m/pix and reconcile an ROI from that image to one that is ~100m/pix. It seems like it won't extrapolate the ~200m/pix ROI and fill in multiple pixels in the 100m/pix image. Is there a way of doing this
Thanks for your time!
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0 |
1144 |
25 Aug 2010 10:15 AM |
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1 Replies and 888 Views
ENVI_DEFINE_MENU_BUTTON 888 1
Started by Deleted User
Hi folks,
I've written an ENVI program that uses the envi_define_menu_button routine. Typically it comes with a distribution of other software written by folks in our group, and the routine makes menu items in two places: under the Basic Tools area and also under a separate Tools area in our typical menu structure that includes a top-level menu hierarchy rooted at the same level as "Basic Tools".
I was installing it on another computer for someone who doesn't need the rest of ...
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1 |
888 |
25 Aug 2010 09:07 AM |
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1 Replies and 1138 Views
IKONOS > converting DN to radiance 1138 1
Started by Deleted User
Hello all,
I am attempting to convert raw DN values of an IKONOS image from 2008 into radiance values (W m-2 sr-1 um-1). I'm assuming I can use spectral math with the conversion coefficients, but I'm just not sure which coefficients to use. There seem to be several values listed rather vaguely in the literature. Has anyone done this recently that could direct me on the right path
Thank-you in advance for your time,
Jenn
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1 |
1138 |
23 Aug 2010 06:37 PM |
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0 Replies and 1084 Views
Using Where and Reform to mask out values 1084 0
Started by Deleted User
Hello-
I am trying to calculate a mean value for EVI reflectance in a MODIS image with 11 bands. I would only like to use the pixels with values between 0 and 1. Some pixels have values outside of this range. I have tried to do this using the 'WHERE' and 'REFORM' function.
temp is the 11 band image.
I am using the code:
good_data=temp&91where(temp GT 0 AND temp LE 1,count)&93
if (count GT 0) then continue
temp=reform(temp&91good_data&93,cou...
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0 |
1084 |
22 Aug 2010 07:49 AM |
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1 Replies and 1293 Views
Colour Balance 1293 1
Started by Deleted User
Hi All,
I'm trying to colour balance three ASTER granules without creating a mosaic. Is there a handy ENVI way of doing this Also, when I tried to mosaic two of the images and colour balance them just to see if it would work, I recieved an error after the statistics were calculated that said it couldn't 'converge' and that the output might be inaccurate -- there was no output though and no new image was generated. Does the colour balancing function in the mosaic tool use some kind of simula...
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1 |
1293 |
19 Aug 2010 12:33 PM |
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2 Replies and 1174 Views
Using the 'where' function makes converts a 2-d array to a 1-d array 1174 2
Started by Deleted User
Hi all-
I am using ENVIIDL to calculate EVI from MODIS images. It uses a times series with each band becoming a band in a multi-band image. I then use the 'where' function to mask out values before calculating mean, max, min, median values. Unfortunately when I use the 'where' function my multi-band image becomes 1 diemensional, and my calculations do not work. They work fine before using the where function.
Here is how I use the function
good_data=temp&91where(temp GT 0 A...
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2 |
1174 |
18 Aug 2010 07:38 AM |
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14 Replies and 2345 Views
ENVI coordinate bug? 2345 14
Started by Deleted User
Hi All,
I've been using ENVI for a few weeks now and I have had nothing but problems with an annoying 'bug' in the program. I'm not sure if it's appropriate to report it as a bug though since it's possible that I'm just missing something. I have ASTER L1B data in .hdf format from NASA that I've opened in ENVI and processed in a number of ways. It seems that nearly everytime I open ENVI to view or process my data the corrdinates in the header files are different. In some cases, after a proces...
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14 |
2345 |
17 Aug 2010 12:24 PM |