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1 Replies and 1682 Views
Technically, what is the difference between photo, image, picture and raster? 1682 1
Started by Deleted User
Technically, what is the difference between photo, image, picture and raster
do they mean the same or there is some distinction
is it true to say:
" Normal 0 false false false EN-US X-NONE AR-SA Remotely sensed data can be obtained in two main forms: as image or photo. Image refers to the data collected by electronic sensor while photo refers to data acquired by camera lens (film) (Decker 2001).
These two devices (camera and sensor) can be carried in several ways to collect data: ai...
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1682 |
10 Jun 2011 04:15 PM |
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2 Replies and 1456 Views
Incorrect UTM to Lat/lon conversion using GeoTIFFs in ENVI 4.5 1456 2
Started by Deleted User
I am writing an application that generates GeoTIFF files and trying to use ENVI 4.5 to validate them. I am seeing a strange conversion from UTM co-ordinates to lat/lon when the GeoTIFF has a custom defined ellipsoid and projection.
As a test, I set the ellipsoid and Traverse Mercator values to be equal to UTM Zone 22S and WGS-84 and saved one GeoTIFF specifying a custom CS and one GeoTIFF using the named projected CS type.
The GeoTIFF fields, as far as my limited understanding go...
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1456 |
07 Jun 2011 02:22 PM |
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2 Replies and 1438 Views
merging files with different wavelengths 1438 2
Started by Deleted User
Dear all
I would like to merge two sets of hyperspectral imagery for a single small study area into one file for further processing. I want this file should include all the wavelengths of the two base files for each pixel, however when I use the pixel mosaic function mosaic the wavelengths of one file are always overwritten.
eg file 1 has 63 bands
(405-995nm)
file 2 has 266 bands
(1001-2466nm)
mosaic output has 266 bands
(1001-2466nm)
As you can see, ...
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1438 |
07 Jun 2011 06:55 AM |
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1 Replies and 1382 Views
Merging two classification in single file 1382 1
Started by Deleted User
Hello,
I have used change/nochange mask to classify single TM data separately, one using change mask and other using no change mask. Now I have two classifications from two mask for same data. I donot know how to merge them into a single classification file.
Please help me
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1382 |
06 Jun 2011 02:56 AM |
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2 Replies and 1259 Views
Change Detection 1259 2
Started by Deleted User
Hi,
Is there any way to use two difference images Diff1 and Diff2 as (Diff1 = Tim2-Time1) and Diff2 = (Time3-Time2) to find changes between Time1 Time2 and Time3 in one change image.
Thanks
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1259 |
05 Jun 2011 07:39 PM |
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1 Replies and 1699 Views
Band Threshold to ROI- Polygons? 1699 1
Started by Deleted User
Hi,
I am have been using "band threshold to ROI" to classify my image. I ultimately need shapefile polygons to work with in Arcmap. When creating the new ROIs I have "polygon" selected under roi_type in the ROI tool but I get points every time, and cna't figure out an efficient way to convert the points to polys.
Thanks!
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1699 |
02 Jun 2011 03:06 PM |
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2 Replies and 3299 Views
How to convert integer to floating point? 3299 2
Started by Deleted User
Hey Guys,
I am trying to convert ND to reflectance in MODIS images, so I edited the reflectance scale factor to 10,000, but when I try to edit the data type, changing from integer to floating point, a problem message pops up
“Problem: Specified dimensions are incorrect, they total double size”
Can you help me
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2 |
3299 |
27 May 2011 06:40 PM |
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1 Replies and 1239 Views
Output to JPEG with stretch 1239 1
Started by Deleted User
Hi,
I'm working with ENVI and IDL. When I open an RGB image in ENVI, it applies a linear 2 stretch which I'm able to save as JPEG for use. While this is convenient, I can't open the GUI for say a 1000 files. Unfortunately, I don't see a programmatic way of doing this using ENVI functions. I would like to retain the 2 linear stretch in the JPEG outputs which I'm not able to, using IDL or other tools. I think I'm missing something here.
Is there a way to apply a 2 linear stretch o...
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1239 |
27 May 2011 04:03 PM |
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12 Replies and 1426 Views
Problems with using SPOT_calibrate.sav 1426 12
Started by Deleted User
Hi all,
I am trying to use the SPOT_calibrate.sav, but somehow it does not work. This is what I do:
- I open the satellite image through open external file, DIMAP, and select the .dim file
The file opens.
Then I start the SPOT Calibrate function, and select the opened file. When asked for the metadata file, I select the same .dim file. And then nothing happens (although ENVI is "thinking"). When I try to close ENVI it says that IDL has encountered an error.
Anyone a...
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1426 |
26 May 2011 07:01 AM |
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4 Replies and 2541 Views
Must wavelenghs defined to calculate vegetation indices 2541 4
Started by Deleted User
help,
By using the menu vegetation index calculator the following error occurs:
"Must wavelenghs defined to calculate vegetation indices"
What should I do to follow the analysis
Att
Carlos Magno
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4 |
2541 |
24 May 2011 08:04 PM |
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3 Replies and 983 Views
Image difference for change detection 983 3
Started by Deleted User
Hello,
I am tryying to identify changes using three date composite image using image diffrence technique. I got two date difference images as Diff1 = Date2-Date1 and Diff2 = Date3-Date2.
My problem is , I want to detect three-date composite change as YYN, NNY, YYY, NNN etc. where YYN stands for presence of a class in Date1 and Date2 and not present in Date 3 and so on.
1. I know there is s method called RGB-NDVI which depicts the changes based on RGB combination of each date...
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3 |
983 |
23 May 2011 04:10 AM |
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1 Replies and 1536 Views
error importing HYPERION Level 1R using Hyperion Tools 1536 1
Started by Deleted User
'The following error was encountered: HDF_SD_SELECT: Unable to select the HDF-SD dataset (SDINTERFACE_ID). Please consult the supplier of the application.'
Please advise.
Thanks,
A. Mah
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1536 |
21 May 2011 11:07 PM |
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1 Replies and 1510 Views
supervised classification 1510 1
Started by Deleted User
I have a polygon shapefile with several attributes. One Attribut is a number which represents a landuse class which was created by ground truth data.
Now i want to do a supervised classification using maximum likelihood and I want to use this attribut of my shape file to define my training regions. Here I struggle. When I load my shapefile every polygon is a single region and I don't see how I can group them by the same attribut.
I saw that Envi Fx has the option to use ground tuth attri...
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1510 |
20 May 2011 03:34 AM |
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2 Replies and 1452 Views
Open .grd and .tab file 1452 2
Started by Deleted User
Hi All,
I have this two types of file from MapInfo. This is believes to be the vector file but i'm confuse to open the file using ENVI in proper way. Please anyone help. I want to open the file using version 4.8.
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1452 |
19 May 2011 12:49 AM |
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5 Replies and 1588 Views
code for batch unsupervised classification with mask 1588 5
Started by Deleted User
Hello,
I'm trying to run an unsupervised classification (ISODATA) with the same mask image on jpg files in a folder through a loop and put the output files in another folder. I get the classification running ok, using a code for batch generating NDVI images that I found some time ago on the ITT website. I tried to modify this code to do the ISODATA classification that generates two classes and should apply a mask also. However, the outputs I get don't have the mask applied but instead the...
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5 |
1588 |
18 May 2011 12:54 PM |
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1 Replies and 1481 Views
access deny when download 1481 1
Started by Deleted User
I apply for an account and plan for downloading the Envi 8 .but the webpage show me "Access Deny"
why and how to download what is the problem
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1481 |
17 May 2011 06:41 AM |
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1319 |
16 May 2011 07:22 PM |
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1296 |
16 May 2011 07:22 PM |
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1 |
1232 |
16 May 2011 07:22 PM |
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0 Replies and 1758 Views
READU error message in ENVI 4.7 1758 0
Started by Deleted User
Hi, I am new to using ENVI and to remote sensing but I am attempting to mosaic some SRTM data in ENVI. I have downloded 8 DTED files from USGS covering my study area and can read them into ENVI using
open extrenal file > digital elevation >DTED
the "DTED Input Parameters" box then appears with my files listed, I keep "mosaic files" selected and choose an output filename, a box appears to inform me that "Dimensions of output DEM are computed to be 3601 x 4...
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1758 |
13 May 2011 07:51 AM |