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2 Replies and 1159 Views
Ikonos and NDVI 1159 2
Started by Deleted User
Hi, is there a way to calculate NDVI for an Ikonos image with ENVI It tells me that ENVI can't calculate any VIs with the Ikonos wavelenghts. But then, when delineating vegetation it does calculate an NDVI... is this accurate
Thanks!
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2 |
1159 |
05 Sep 2011 09:33 AM |
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3 Replies and 943 Views
bytscl function in band math 943 3
Started by Deleted User
Hi all,
I'm trying to compare depths of a particular absorption feature derived from a series of different hyperspectral images. I used "bytscl" function and set as "minimum" the minimum from all images (although the value is a lot lower than the lowest for some images), and as a "maximum" the highest value from all images (although it is a lot higher for some). I also stretched the images using their own min and max values (derived through statistical compu...
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3 |
943 |
01 Sep 2011 11:19 AM |
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1 Replies and 1072 Views
PCI FileType 1072 1
Started by Deleted User
I'm updating an ENVI file reader to support yet another 'standard' file format. This new file source has 'File Type = PCI' in the header file. It appears that the data blocks are restricted to 256 byte boundaries for each camera frame. Is this documented by anyone
Thanks,
-Jim
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1 |
1072 |
31 Aug 2011 10:46 AM |
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1 Replies and 1271 Views
using masks in ENVI programming 1271 1
Started by Deleted User
Hi folks -
I am building in some error checking in ENVI/IDL code. I use band math to perform calculations over an entire image, where I am only interested in a subset of the entire image (I use an EVF file early on in the processing to determine values that will be later on applied to the whole image via band math). I would like to, effectively, use the EVF file as a mask over which to see if my processing results fall within a certain range of values. How do I apply an EVF file or ROI...
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1 |
1271 |
29 Aug 2011 04:05 PM |
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3 Replies and 2015 Views
controlling NaN pixels in ENVI scripting calls 2015 3
Started by Deleted User
Is there an easy way, *using ENVI programing calls*, since I am working with imagery already opened with ENVI fids (vs IDL luns) to do this:
(if any pixel in image = 0) then (pixel = NaN)
Where the pixel locations vary, and therefore a mask would not work
I'd like to do something like this in a 'band math' call.
Thank you...
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3 |
2015 |
29 Aug 2011 12:35 PM |
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3 Replies and 4816 Views
Adding Landsat Gap Fill Tool in ArcToolbox 4816 3
Started by Deleted User
Hi, I want to add an ENVI Tool in ArcToolbox so that I can perform Landsat Gap Fill in ArcGIS without opening ENVI. I have written a python script (LandsatGapfill.py) to call 'LandsatGapfill.sav' from ArcMap. python script is mentioned below: Python Code example for calling an ENVI DOIT Routine import arcgisscripting, envipy Get input raster inRasterName = arcpy.GetParameterAsText(0) Get output raster outRasterName = arcpy.Get...
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3 |
4816 |
29 Aug 2011 06:11 AM |
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3 Replies and 1156 Views
Dark Subtract adds value to landsat bands 5 and 7 instead of subtracting 1156 3
Started by Deleted User
Hi Everyone, i'm using ENVI 4.8 to process Landsat 5 tm and landsat 7etm images. After the automatic dark subtract process, i noticed that the reflectance values for band 5 and band 7 are actually higher then the original. Have any1 experienced this before does anyone knows why this is happening Many Thanks in Advance.
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3 |
1156 |
26 Aug 2011 10:14 AM |
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0 Replies and 970 Views
Urgent: Does anyone know the formula for calcuating Local Moran I, in ENVI. 970 0
Started by Deleted User
Does anyone know the formula for calcuating Local Moran I, in ENVI.
I created a sample 5x5 image and calculated "Local Moran I" in ENVI. Parellay I calculated local moran I manually in Excel. I really donot understand what went wrong, in ENVI the values are too low, and no way matching up with the results that I got manually(seriously I tried 10 time, using the formulas from text book).
Any help is appriciated.
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0 |
970 |
24 Aug 2011 11:54 PM |
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1 Replies and 1367 Views
FLAASH error 1367 1
Started by Deleted User
Hi, I'm having troubles in applying FLAASH in a RapidEye, I wonder if anyone could help me. The problem is the following:
ACC error: avrd: No nonblank pixels found
IDL error:
OPENR: Error opening file. Unit: 101, File C:\Program Files\ITT\IDL71\products\envi47\filt_func\rapideye.sli.hdr
The system cannot find the file specified.
ACC_AVRD
ACC_HYPER2
ACC_ACC
ENVI_ACC_EVENT
ENVI_FLAASH_PROCESS_MANAGER
IDLRTMAIN
$MAIN$
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1 |
1367 |
24 Aug 2011 01:17 PM |
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1 Replies and 1225 Views
LISS3-Resourcesat and FLAASH 1225 1
Started by Deleted User
Hello,
I'm starting to work with LISS3 images from Resourcesat and I'm having problems to convert the data to reflectance using FLAASH. This image is in DN and I had convert to radiance. Now I would like to transform in reflectance using FLAASH as it has a option of LISS3 as a sensor type parameter. But the output values from the image are very strange with too high negative values as too high positive values such as -500 and 500.
Could anyone help me I try to change the scale factor a...
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1 |
1225 |
24 Aug 2011 12:59 PM |
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1 Replies and 1351 Views
IDL calling ENVI - different versions 1351 1
Started by Deleted User
Hi folks -
I a, programming in IDL 7.0 with ENVI 4.5. I need to write IDL scripts that call ENVI functions, to simply/speed up my company's specific image processing methods. I have a script that works just fine on my system, but it does not work for one of my coworkers. She is running IDL 6.4.1 with ENVI 4.4. When I run my script on her system, calls to, for example, "ENVI_OPEN_FILE' are recognized, but when I call 'MATH_DOIT', IDL claims it does not recognize the function. Can...
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1 |
1351 |
23 Aug 2011 05:02 PM |
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1 Replies and 1380 Views
WorldView-2 radiance equation 1380 1
Started by Deleted User
what equation does Worldview-2 use for the calculation of radiance
and what is the reference for it or which paper is it in thanks
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1 |
1380 |
22 Aug 2011 04:09 PM |
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2 Replies and 1321 Views
layer stacking 1321 2
Started by Deleted User
I have been using ENVI for some time. Somehow I always used stacked images (done from other sources). Recently I tried to use layer stack option to stack Hyperion data. I must say, it it is very useful and time saving (took less than 2min to select and stack 242 bands). But the problem is, output is always in descending order; spectral plots starts from 2500 nm and ends at 400 nm (ideally it should be mirror image). I want this in ascending order. Reordering the bands during stacking is one opti...
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2 |
1321 |
22 Aug 2011 04:08 AM |
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2 Replies and 1379 Views
error opening Landsat MSS metadata 1379 2
Started by Deleted User
dear all,
I struggle opening a Landsat MSS Geotiff with metadata, downloaded from the earth explorer.
When I try to open the .MTL file, I get the following error:
GEOTIFF METADATA File ......_MTL.txt
Problem: an error was encountered reading this file.
Error: Expression must be a scalar or 1 element array in this context: .
it then opens 6 bands, the first 2 are just black. The metadata for the processing is wrong then, of course.
I'm using Envi 4.7 and the 4 Geotiffs are in the sam...
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2 |
1379 |
16 Aug 2011 08:44 AM |
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4 Replies and 1420 Views
Problem with NDVI after FLAASH 1420 4
Started by Deleted User
Hello, Excuse me about my precarial English. I'm a new ENVI user from Ecuador and I have some questions about an ENVI process that I'm developing. I have 3 ASTER 1B images from different ages of the Ecuadorian Amazon Rainforest and I need to analyze them for a multitemporal study. In first place I transformed them into a BIL image and then, I ran the FLAASH algorithm from ENVI 4.7, In the requirement of 'Radiance Scale Factors' I typed 10 as it is said in many forums because of the radiance uni...
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4 |
1420 |
15 Aug 2011 09:08 AM |
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1 Replies and 1214 Views
Exporting Tasseled Cap to ArcGIS 1214 1
Started by Deleted User
I've got some "greenness" and "wetness" bands that I just processed and need to export to ArcGIS. What is the process
I tried "save image as" using the ArcView format and it is readable by ArcGIS but there isn't any spatial information attached and I can't figure out how to add that. Any help/direction would be appreciated. Thanks,
Nathan
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1 |
1214 |
10 Aug 2011 04:26 PM |
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1 Replies and 1123 Views
difference in values from ENVI script vs. 'band math' 1123 1
Started by Deleted User
Hi folks -
I am working on automating several raster processing steps that my company does, by writing ENVI / IDL scripts vs. the more tedious act of going through the ENVI gui interface, when needing to run many images. I am performing simple arithmetic operations on Landsat scenes, and using 'math_doit' in the script to perform the math. It is my understanding when one uses the GUI interface and uses 'band math', this also calls the math_doit function, isn't that right However, wh...
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1 |
1123 |
10 Aug 2011 01:28 PM |
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4 Replies and 2161 Views
mosaic / layering problems 2161 4
Started by Deleted User
Hi there,
So I have mosaiced several landsat images together (about 15 path/rows). I have ran into trouble with correctly mosaicing bands 1-5 and 7. The first band is good, but the other bands have significant gaps in-between each image, with increasing gap size towards band 7. I have tried to avoid this problem by mosiacing each individual band, and then layer stacking them and editing the header file afterwards. When I layer stack each mosaiced band, I run into an error about half way:
...
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4 |
2161 |
10 Aug 2011 09:34 AM |
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1 Replies and 1220 Views
tiling and 'math_doit' 1220 1
Started by Deleted User
Hi folks - I need to write some custom band math functions that get called from an ENVI/IDL script. I am using 'math_doit' to make the calls. I'm running into memory problems, though. Isn't it the case that math_doit automatically uses tiling, or do I not understand correctly
If I need to do the tiling 'by hand', can someone please point me towards a good reference to learn how to do so within a script. Thank you!
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1 |
1220 |
08 Aug 2011 09:59 AM |
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1 Replies and 1667 Views
FLAASH Problem 1667 1
Started by Deleted User
After performing all the steps like
Calibrating the TM Image into Radiance (Radiance Calibration)
Adjusting the radiance unit using band math b1/10
Converting the interleave into BIL format
And inputing various parameter into FLAASH Atmospheric Correction Model Input Parameters
After clicking on Apply
I get following Envi error
File: C\Master Thesis\ TM\ TM_FLAASH_template.txt
Problem: No carriage returns found. Unable to read this file as an ASCII file.
...
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1 |
1667 |
05 Aug 2011 11:34 PM |