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0 Replies and 1466 Views
Band Math 1466 0
Started by Deleted User
Hello fellow ENVI users:
I am hoping that somebody out there has used the Band Math function successfully. I am trying to calculate a vegetation index (b1 - b2)/(b1 b2). ENVI happily chugged along and output an image, but the values are not what they should be: they should range from -1 to 1, but are ranging from 0 to 255 when I used the Cursor Location or Statistics function, which tells me that a stretch is being applied somewhere. I need the true unstretched data values, but can't fin...
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1466 |
30 Nov 2005 12:57 PM |
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2 Replies and 1709 Views
Band Math 1709 2
Started by Deleted User
Hello fellow ENVI users:
I am hoping that somebody out there has used the Band Math function successfully. I am trying to calculate a vegetation index (b1 - b2)/(b1 b2). ENVI happily chugged along and output an image, but the values are not what they should be: they should range from -1 to 1, but are ranging from 0 to 255 when I used the Cursor Location or Statistics function, which tells me that a stretch is being applied somewhere. I need the true unstretched data values, but can't fin...
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2 |
1709 |
30 Nov 2005 12:57 PM |
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0 Replies and 1467 Views
Band math 1467 0
Started by Deleted User
Hi,
I am a new user of Envi and I knew very little about band math. I want to write an expression in band math, but I didn¡¯t know how to write it. Please help me and thank you very much.
255
h(x)= - ¡Æ Pi * Log2 Pi
i=0
where:
Pi is the probability that the pixel grey value is equal to i;
x is the input image variable;
LP
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1467 |
30 Nov 2005 12:57 PM |
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0 Replies and 1848 Views
Band Math 1848 0
Started by Deleted User
I want to ask that wheather there is any function for anti-log in the Band Math function How to write the anti-log function For example, my algorithm is log(x), and i want to get x value.
Thank You.
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1848 |
30 Nov 2005 12:57 PM |
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1 Replies and 1832 Views
Band Math 1832 1
Started by Deleted User
When I do a simple Normalized Differential Vegitation Index (NDVI) calculation using band math with LandSat 7 TM data using, bands 4 and 3 via (b4-b3)/(b4b3). I expect to get numbers between -1 and 1, but I do not. When I look at the calcualted band image vs. the 'canned' NDVI calculation done via the ENVI NDVI funtion they look very different. Does anyone have any Idea where I am going wrong
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1 |
1832 |
30 Nov 2005 12:57 PM |
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0 Replies and 1547 Views
Landsat TM Calibration Utility - Input Parameters 1547 0
Started by Deleted User
Hi!
I have 1990 TM scenes and want to convert DN values into spectral radiance.
In ENVI's Calibration Utility for Landsat TM data what are the input parameters that ENVI calls ScaleMin and ScaleMax
In the Help they are defined as satellite parameters set for each band used to derive the gains and offsets (Gains and offsets would not need to be calculated because they are contained in Landsat TM header file!)
Are ScaleMin and ScaleMax maybe the lower (Lminë) and upper (Lmaxë) limits of the...
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1547 |
23 Nov 2005 09:36 AM |
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1 Replies and 1574 Views
Image Processing 1574 1
Started by Deleted User
Hi:
Would any one let me know how to do step by step High resolution Image Analysis. Regards,
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1 |
1574 |
17 Nov 2005 07:09 PM |
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0 Replies and 1603 Views
Use ENVI 4.2 to open ESRI GRID file 1603 0
Started by Deleted User
Hi,
I generated a monthly temperature surface with Kriging function in ESRI ArcMap 8.3, and then I exported the data to raster whose format is ESRI GRID.
I tried to open the file with ENVI 4.2 but failed. The ENVI 4.2 couldn't recognize the file. But it is showed that ESRI GRID is one of the supported input file format in ENVI User's Guide.
Has anyone met the same problem and already fixed it I am looking forward to your help. Thanks!
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0 |
1603 |
17 Nov 2005 02:43 PM |
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0 Replies and 1707 Views
dual monitor - default window positions 1707 0
Started by Deleted User
I'm just getting started with ENVI, and got a dual monitor system to run it on. I'd like to have my display, zoom, and scroll windows open on the second monitor by default. I know where in the preferences to set the default window sizes, but have not found the placement options I'd like.
Any suggestions
Thanks!
-Eric
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1707 |
14 Nov 2005 10:56 AM |
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1 Replies and 1520 Views
Image classification 1520 1
Started by Deleted User
We’ve got a serious technical problem on ENVI. We have LISS and PAN images to be processed. The classification is successfully completed in LISS image. But while classifying the fused image the following error comes.
'Error: “Error encountered writing to file, Unit:101,File:C:\trial” the result may be invalid”'
The size of the fused image is 4 GB, and we have 20 GB of free space in our system with 1GB RAM.
What might be the cause of this error
Any help regarding this will be hi...
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1 |
1520 |
14 Nov 2005 03:51 AM |
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0 Replies and 1747 Views
orthorectify 1747 0
Started by Deleted User
Hello forum, I'd like to ask about quickbird orthorectify, how can I know the polynomial number that I'm using , I don't find this in nowhere of my window!, thanks in advanced for any hint
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0 |
1747 |
10 Nov 2005 09:02 AM |
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1 Replies and 2037 Views
Select multiple files 2037 1
Started by Deleted User
Hi!
I need to select multiple files from the ones already opened in ENVI.
Some of the example on RSINC site use the ENVI_SELECT function as above
envi_select, title='select images', /multiple, mfrs=mfrs, $
/no_spec, /no_dims, /file_only
This example doesn't work on my ENVI 4.1 because MFRS is not allowed in ENVI_SELECT function. Also the 'multiple' keyword is not documented on the ENVI help files (deprecated).
So how can i select multiple files What function should i use
I need a...
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1 |
2037 |
09 Nov 2005 02:23 AM |
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0 Replies and 1635 Views
Band maths 1635 0
Started by Deleted User
I have no knowledge of programming what soever. So please someone help me convert this information into something that the band maths function can recognize and respond to.
'If b1 is greater than 10 (integer) then null else b2'.
Thanks.
b1 and b2 are individual bands. 10 is an 8 bit integer
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1635 |
08 Nov 2005 06:03 AM |
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0 Replies and 1847 Views
Export image to Erdas .lan 1847 0
Started by Deleted User
Hi
I need to export some LANDSAT images that are currently in PCI Geomatics .pix format, into ERDAS .lan format, in order to use the data in a custom model. Does anybody know how to save as .lan in ENVI 4.2 I can find .img but not .lan.
Cheers,
Jason
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0 |
1847 |
07 Nov 2005 01:37 PM |
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0 Replies and 1968 Views
12-bit packed data 1968 0
Started by Deleted User
I would like to display some images from a 43-channel scanner I am testing. The problem is that the scanner output 12-bit BIP data packed into 16-bit. Is there any way to open such data in ENVI 3.6 Thanks in advance.
Wilki
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0 |
1968 |
06 Nov 2005 05:27 PM |
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0 Replies and 1770 Views
12-bit packed data 1770 0
Started by Deleted User
I would like to display some images from a 43-channel scanner I am testing. The problem is that the scanner output 12-bit BIP data packed into 16-bit. Is there any way to open such data in ENVI 3.6 Thanks in advance.
Wilki
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0 |
1770 |
06 Nov 2005 05:27 PM |
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0 Replies and 1804 Views
DEM edit? 1804 0
Started by Deleted User
Hey all,
I'm trying to figure out if it's possible in ENVI to directly edit the Z values in a DEM cell I can't seem to find any reference to this procedure in any help files.
Thanks! Bob
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0 |
1804 |
03 Nov 2005 01:51 PM |
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0 Replies and 1625 Views
Batches processes using ENVI 1625 0
Started by Deleted User
Hi,
I need to make some batches processes using ENVI. The batches process should run on single command on multiple files, multiple commands on single file and multiple commands on multiple files.
Thanks for any idea.
Gil
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0 |
1625 |
02 Nov 2005 01:24 AM |
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0 Replies and 1839 Views
Calibrate RADAR to Sigma Nought 1839 0
Started by Deleted User
Can a person calibrate RADARSAT imagery to Sigma Nought (RADAR - Calibration - Sigma Nought) without a DEM I have ocean data, so there is little need for a DEM.
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1839 |
27 Oct 2005 09:03 PM |
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1 Replies and 2343 Views
Programmatically convert Shapefile to EVF to ROI 2343 1
Started by Deleted User
Hi everybody,
I want to programmatically convert several shapefiles to EVFs and then to ROIs, in a script.
So far, I haven't found any way of doing it. Any ideas Solutions Suggestions.
Thanks a lot!
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1 |
2343 |
26 Oct 2005 05:40 AM |