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0 Replies and 1572 Views
Flat Field for ASTER? 1572 0
Started by Deleted User
Is it possible to use the flat field atmospheric correction procedure to correct for ASTER data I get the impression that the flat field is for hyperspectral data alone, but I have tried it out on ASTER and I have got some results. I am not sure if the results wont be thrown out by my super, if flat field is only for hyperspec data. So I'd like to know, anyone...........
Thanks
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0 |
1572 |
07 Mar 2006 08:06 AM |
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1 Replies and 1815 Views
Texture Measures 1815 1
Started by Deleted User
I am familiarizing myself with deriving texture co-occurence measures in ENVI. Could someone please confirm the following:
- If I want to change the look direction/orientation of my texture filter to 135 degrees (i.e., to find relationships of a pixel with its neighbour 135 degrees or southeast), would I change the 'Co-occurrence Shift' in ENVI to:
X=1, Y=-1
This seems rather intuitive, but my results appear 'strange' when I use those parameters. Thanks,
Randall
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1 |
1815 |
06 Mar 2006 09:42 AM |
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0 Replies and 1967 Views
reampling: pixel aggregate 1967 0
Started by Deleted User
Could you give me some clue on pixel aggregate or som explaination
Thank you !
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0 |
1967 |
05 Mar 2006 12:30 PM |
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1 Replies and 1667 Views
best way to align rasters? 1667 1
Started by Deleted User
Hi,
I have several rasters in the same projection, but with different coordinates for the upper-left corner. I need to do some modeling though BandMath functions, but it seems to require perfectly alligned rasters. I've managed to solve the problem in the past through layer stacking, but I think that will only work if they are all of the same data type(). I now need to model with rasters of byte, long, and double types. What would be the best method for aligning these Is there a resampli...
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1 |
1667 |
03 Mar 2006 04:42 PM |
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0 Replies and 1623 Views
Create Solid (filled) vector out of polyline 1623 0
Started by Deleted User
I have a coastline (and some island coastlines) as a vector file. What I'd like to do is 'close' or 'fill' those vectors to essentially create a land mask (i.e., each polyline is now a filled polygon). Can I achieve this
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0 |
1623 |
03 Mar 2006 10:12 AM |
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0 Replies and 1466 Views
choosing an open EVF when scripting... like ENVI_SELECT but for EVF 1466 0
Started by Deleted User
I'm writing a script (IDL... so maybe I should be posting to that forum, but it is probably an ENVI specific function that I need). I'd like to be able to bring up a dialog for selecting an EVF file that is already open... analagous to the ENVI_SELECT for choosing raster files or bands. Is there one
Thanks,
-Eric
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0 |
1466 |
28 Feb 2006 02:36 PM |
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0 Replies and 1494 Views
polarization signature 1494 0
Started by Deleted User
Hi,
I want to extract the polarization siganture for each pixel in SIR-C image and later analyse the result in ArcGIS.Can anyone please tell me in hwat format i have to obtain the polarization siganture for each pixel, like ASCII or other format so that i can then analyse the SIR-C image in GIS with the polrization signature results.
Thanks,
Indu.
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0 |
1494 |
28 Feb 2006 12:05 PM |
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0 Replies and 1476 Views
Macro in ENVI? 1476 0
Started by Deleted User
Hello group,
Similar to macro functioanility in Microsoft Visual Basic Applications, are there any functionanility in ENVI to record in IDL format, all the steps performed in ENVI GUI By that way, I can open that IDL file and edit it, instead of writing from scratch Thanks in advance.
Jeyam
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0 |
1476 |
27 Feb 2006 07:55 AM |
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0 Replies and 1372 Views
Image sharpening:HLS 1372 0
Started by Deleted User
Dear ENVI user,
I want to merge a low-resolution color image with a high-resolution grayscale image by means of ENVI image sharpening (HLS). From the ENVI4.2 user¡®s guide : transform/image sharpening, I not only learned how ENVI performed the HSV and HLS sharpening, but also that HLS sharpening can be performed the same way as HSV if some of the parameters in the routine RGB_TRANS_DOIT are changed. Because I am a new user of ENVI, and I knew very little about the IDL. I sincerely hope someone ...
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0 |
1372 |
27 Feb 2006 12:46 AM |
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3 Replies and 1486 Views
Reflectance 1486 3
Started by Deleted User
Hello Group:
I have a hyperspectral image of an object, and an image of white reference and an image of 'dark'. I want to calculate reflectance by taking each band in the hyperspectral image, subtract dark image, and then divide it by (white-dark) image. How do I do this operation in ENVi or IDL
Thanks.
Jeyam.
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3 |
1486 |
25 Feb 2006 06:27 PM |
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0 Replies and 1432 Views
Atmospheric water vapour content 1432 0
Started by Deleted User
Hi everyone,
Does anyone know where I can get the data of atmospheric water vapour content, which is one of the important parameters for calculating the land surface temperature. I can only get the precipitable water data from NASA.
However, I have no idea what is the relationship between them. And whether I can use the precipitable water data for the calculation.
Thank you very much
cheers,
AJ
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0 |
1432 |
24 Feb 2006 02:32 AM |
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0 Replies and 1547 Views
Saving Batch intermediate results 1547 0
Started by Deleted User
Hello fellow ENVI users:
The argument 'out_name' in envi_avhrr_calibration_doit (and all other envi_doits) expect a string and does not allow sending the result of an expression. Placing the doits in a loop for batch processing will only write over the same files. How can I save the results of each loop if I cannot change the output file name
Thanks
Spiros
ENVIIDL 4.2 on WindowsXP
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0 |
1547 |
23 Feb 2006 09:35 PM |
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0 Replies and 1676 Views
Extract image's pixel value from point map 1676 0
Started by Deleted User
Dear list,
I have a point map in GIS format which I can import and read in ENVI as a vector *.evf file.
What I want to do is to extract pixel value at every point on the vector file. In a GIS environment it would be easy using a query, but since ENVI (and other Image software) dose not have query, I still not figure out a straight way for this task.
With some hybrid software like ILWIS (the one from ITC) we can rasterize a point map, then cross it with the target map to get statistic da...
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0 |
1676 |
23 Feb 2006 09:30 PM |
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0 Replies and 1936 Views
layer stacking 1936 0
Started by Deleted User
I am working on layer stacking of the Green, Red, IR and Medium Infrared bands of IRS LissIII image. I tried to put toghether the 5 bands --blue, green, red, IR (25 m resolution) and medium IR (70 m resolution) by means of ENVI 4.2 Layer stacking but it does not seem to work. Is it possibile to put toghether these bands somehow... resampling the 70m band etc
Thank you
loris
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0 |
1936 |
22 Feb 2006 10:51 AM |
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1 Replies and 1644 Views
layer stacking 1644 1
Started by Deleted User
Hi to all,
I have a problem with Layer stacking. I have two Hyperion images and i have to apply layer stacking in some bands of each image. One image giving the result correctly but whenever i apply the method on other image an error like this occurs ' Array dimensions must be greater than zero'.
Is there someone who could help me to resolve this problem.
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1 |
1644 |
22 Feb 2006 10:51 AM |
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0 Replies and 1678 Views
envi error 1678 0
Started by Deleted User
hi to all
Iam processing a hyperspectral image has 242 bands.
but whenever i apply the Envi_get_data function an error prompt for Envi like this occured.
error: readu : End of file encountered. unit :100 ;
file : ' filename ' . The result may be invalid.
The problem is not for those images have less no of bands. (upto 224)
could anybody help me.
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0 |
1678 |
20 Feb 2006 03:45 AM |
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1 Replies and 1525 Views
band minimum 1525 1
Started by Deleted User
hi everybody
I am trying to calculate the MIN of NDVI. I have a layer stack image with 23 bands. I did already the maximum, but with the minimun it is not working. It is because the process take the cero value that have some of the pixels in each band. Somebody know how can I avoid to take the cero. the formule that I used is: b1
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1 |
1525 |
11 Feb 2006 04:18 PM |
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0 Replies and 1727 Views
vector to raster 1727 0
Started by Deleted User
hello everybody...
I am looking for the way to change from vector , shapefile to raster in ENVI. it is a land use map and I would like to convert into raster, because i would like to analyze the type of land use by pixel from 250 meters MODIS resolution. thanks in at advance..
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0 |
1727 |
10 Feb 2006 02:19 PM |
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0 Replies and 1377 Views
Error from spectral reflectance calculation with Empirical line module 1377 0
Started by Deleted User
I utilize Empirical line moduleto calculate reflectance of Hypeion data with image spectra and field spectra(ASD) , an error always appears, 'Variable is undefined: XAXIS', and the result image is wrong. Please help me to resolve this problem.
Thanks,
ZHANG
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0 |
1377 |
09 Feb 2006 08:21 PM |
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0 Replies and 1567 Views
pushing memory limits with 64-bit OS? 1567 0
Started by Deleted User
I'm using ENVIIDL 4.2 on a Windows XP 64-bit box with 4 GB physical RAM. The ENVI config file seems limited to 2GB of RAM (at least, any more than that entered into the System Preferences dialog goes to a negative value). I've read the Tech Tip on memory ( https://www.rsinc.com/services/techtip.aspttid=3346 ) so I understand that the limit would be difficult to push with a 32bit OS (though they imply there is a way to push it to 3GB, but dont provide instructions). Since ENVI is compiled as...
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0 |
1567 |
31 Jan 2006 02:15 PM |