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3 Replies and 1131 Views Default pixel size when applying GLT  1131  3 Started by  Deleted User When operating ENVI from the menu (interactively), when you want to georeference from GLT, after selecting the GLT and the image, one of the items already filled in is a box with a default pixel size. When writing a program, is there a way obtain this default value That is, is the some ENVI or ENVI_doit call that returns this BEFORE applying a GLT I know it is returned when using envy_doit to apply the GLT, but that is only after the GLT is applied. Thanks.
3 1131
27 Feb 2013 10:02 AM
1 Replies and 1363 Views Masking, Jenks in ENVI?  1363  1 Started by  Deleted User Hello, I'm new to ENVI and have a question about classifications: I need to run some stats on various classifications of vegetation data. I can easily do this with the ENVI supervised and unsupervised classifications but am having trouble with Jenks/natural breaks. I've tried using a decision tree with ArcGIS-generated natural break values, but because the ENVI-generated masked image cannot have "nodata" mask value and needs a defined value, the Arc Jenks distribution is being s...
1 1363
25 Feb 2013 10:19 AM
1 Replies and 1503 Views No-Data Pixel After Mosaicking  1503  1 Started by  Deleted User Hi~ I try to mosaic a set of hyperspectral images. However, after mosaicking, a lot of black pixels(no-data) appeared on overlapping area and edge area. My input data is 16 bits(1~2^16) and there are no such black pixels before mosaicking. It should not happen. My Options: Data Value to Ignore = 0, Feathering Distance = 10~50, No Color Balancing. I must use Feathering because there are some bad data (low value) in edge on every image, or is there any way to mosaic images using the max value ...
1 1503
23 Feb 2013 01:34 AM
2 Replies and 1737 Views Unable to acquire device context message and Preference setting  1737  2 Started by  Deleted User I use CentOS 6.3 and ENVI 5.0 sp2 Runtime. I have no problem using ENVI classic. But when I launch New ENVI, I got the messages like this. On Shell : IDLGRSRCDEST::DRAW: Failure to acquire window rendering context On dialog message box : Internal Error: Unable to acquire device context And I cannot use New ENVI. Could someone help me to solve this problem I just guess it might be a Graphic Card related problem. So, I decided to turn off the Graphic Acceleration option in the preference. B...
2 1737
21 Feb 2013 09:59 PM
3 Replies and 2939 Views spectral separability  2939  3 Started by  Deleted User I could see the values transformed Divergence and Jefferies- Matusita Distance ranges from 0 to 2. but it is actualy not in literatures. For eg Tranformed divergence value ranges from 0 to 2000 and Jefferies- Matusita Distance ranges around thousand. Is it right way to multiply the envi values by thousand to get the original values
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19 Feb 2013 06:06 AM
1 Replies and 1351 Views landsat Gap Fill  1351  1 Started by  Deleted User Hi Please am trying to perform landsat gap fill using 2 band gap fill ( but global and local). but I have black output result. please i need your help Is it ok to use &91Gap_Mask&93 provided by USGS together with the landsat image.
1 1351
14 Feb 2013 12:33 AM
4 Replies and 1219 Views rule based feature extraction not working  1219  4 Started by  Deleted User Hi, I am trying to use the rule based feature extraction in ENVI5, but an error saying " internal error: OBJ_NEW" keeps happening. It seems like the function cannot compute attribute values since the attribute histogram does not work and I cannot set rules based on attribute values. Does anyone have the same problem Really appreciate any ideas or clues about how to fix this problem. Thanks again!
4 1219
11 Feb 2013 10:18 AM
1 Replies and 1257 Views orthorectification  1257  1 Started by  Deleted User I have set of L1T hyperion image.The filename is EO1H1440512002081110PY. Should we orthorectify L1T Hyperion images Where do I get the DEM from
1 1257
08 Feb 2013 12:50 AM
1 Replies and 1320 Views cube or stacked  1320  1 Started by  Deleted User Hello!! I have a set of radiometrically corrected Hyperion images. I want to perform atmospheric correction on these images. My question is should we perform layer stacking and then perform atmospheric correction or build an image cube and perform correction on the cube
1 1320
07 Feb 2013 08:45 AM
1 Replies and 1612 Views Bsq format  1612  1 Started by  Deleted User Hello, May i know how to obtain .bsq format using envi. Because i want to used envi file in atcor. However when i save my image in envi it shows .img format. How i want to convert it to .bsq format. I really hope that someone can help me regarding on this. Thanks
1 1612
05 Feb 2013 12:24 AM
1 Replies and 1160 Views layer stacking HANDLE NO OVERLAP ERROR  1160  1 Started by  Deleted User Hi all, I'm writing an automatic code where I have to use the "envi_layer_stacking_doit" routine. It could happen that the 2 files to be layered are not overlapping and this will generate an error by mean of a ENVI warning popup and then the program stops processing data Since I have to process a long time series data is there a way to handle this error in order to avoid stopping the running of the program Thanks in advance
1 1160
04 Feb 2013 12:11 AM
1 Replies and 1203 Views Reprojecting/resampling classification images  1203  1 Started by  Deleted User ENVIers: When resizing or reprojecting classification rasters, many times I would prefer to take the most common class falling within the output pixel, not the nearest neighbor. Is there any trick to doing this with ENVI Bilinear and cubic convolution are not appropriate with categorical data, which is why I ask. The only way I could think of would involve making a single image for each class filled with 0s (where the class is not) and 1s (where the class is), do the resample where the outp...
1 1203
31 Jan 2013 02:55 PM
3 Replies and 1424 Views Tasseled Cap tool  1424  3 Started by  Deleted User Hi, supports Does the Tasseled Cap tool works correct on the CASI data. There is only LandSAT sensor type available. I want calculate Soil Brightness Index on the potato crop. I had read one paper where SBI were calculated using ENVI Tasseled Cap tool on CASI data. So, now i am wondering it is true or not. Maybe you could suggest witch bands should i use in some kind of equation. Thanks for the answer.
3 1424
30 Jan 2013 04:04 AM
2 Replies and 1276 Views basic question on automating ENVI functions  1276  2 Started by  Deleted User Hi, I would like to automate some ENVI tasks for a few hundred images. Specifically, I have HDF files from each of which I want to extract certain layers, and then to save these into standard ENVI files. I am familiar with ENVI from the GUI, but I don't think I want to do this for hundreds of HDF files. My question is: do I use ENVI IDL to automate this task, or is there some other way to do it If I have to use IDL, can someone please direct me to some relevant tutorials/documents to get me st...
2 1276
30 Jan 2013 12:45 AM
5 Replies and 1780 Views GRVI in Band Math  1780  5 Started by  Deleted User Hi everyone I would like to know the correct expression of GRVI in band math. I tried to write the many expression, but the result was not realistic. I think the problem in writing is Prioritization of algebraic operations. How can i write the correct expression. I will be glad to help me. Thank you Hadi
5 1780
24 Jan 2013 09:58 PM
1 Replies and 1494 Views getting traing areas from few imagerys  1494  1 Started by  Deleted User Dear Forum is it possible with Envi to set training areas from few different imagerys and with this traing areas perform the supervised classiffication on the third image Lets say I get TTA for forest from imagery A, TTA for wetlands from imagery B and I want to classified imagery C with this definition Thanks in advance
1 1494
23 Jan 2013 01:01 PM
2 Replies and 1323 Views MODIS conversion toolkit -swt_name of MOD11_L2  1323  2 Started by  Deleted User Hi all! I'm using the MCTK in batch mode to analyze a series of MODIS level2 files. Followed the example in user's guide, I sucessfully ran MOD05 files using 'convert_modis_data', but I don't no how to specify the key word 'swt_name' when I convert the MOD11_L2 files. I tried 'MOD11_L2' and 'MOD11', and it didn't work. Any suggestions Thank you!
2 1323
23 Jan 2013 05:25 AM
4 Replies and 1295 Views Correcting MERIS on FLAASH [Problem]  1295  4 Started by  Deleted User Hello, I'm having problems trying to correct MERIS data via FLAASH. The image is a MER_RR__1P (calibrated TOA radiance). I'm using ENVI 4.8 and FLAASH doesn't have MERIS on Sensor Type's list. The thing is, even if I use the UNKNOWN MSI sensor option FLAASH will require a Filter Function (.sli) file and there's no MERIS on the avaible list. So, after georeferencing the image and converting the interleave, I've tried using MODIS on Sensor Type and alsoUNKNOWN MSI modis.sli (witch must be p...
4 1295
22 Jan 2013 07:10 AM
1 Replies and 1129 Views nan data for emissitivity  1129  1 Started by  Deleted User i tried to do land surface temperature using landsat 4 TM image. using ndvi to estimate emissitivity, i found that the value data for water become nan. what should i do i used this algorithm at band math to retrieve emissitivity, 1.0094 ( 0.0047*alog (b1))
1 1129
21 Jan 2013 06:59 PM
5 Replies and 1346 Views Negative NDVI over algal blooms  1346  5 Started by  Deleted User Hi everyone, I'm relatively new to envi, so I know, perhaps, the barest minimum of how to make it work, I'm looking at MODIS L1b 500m data of the Baltic sea and Barents sea in order to attempt to crudely quantify algal blooms. I have an issue with NDVI (and every other vegetation index there is) where green algal blooms report back negative values much greater than the surrounding water and and clouds that escaped masking (e.g. water= -0.3, thick algae = -0.6). I understand that algal blooms...
5 1346
20 Jan 2013 03:32 AM
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