Questions tagged [envi]
A remote sensing and image analysis software package produced by Exelis Visual Information Solutions (Exelis VIS).
291
questions
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OpenSource Remote Sensing Tools for Classifying Roofs
with envi image processing and classification tools, you can get roofs from images with some spectral value and then you can convert it some vector data for your app.
in python with OpenCV which have ...
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11
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1
answer
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What's the binary format of ENVI (Classic) ROIs?
I'm a Pythonist in an office full of ENVI/IDL users. I've created some tools to help bridge the gap, but one big stumbling block is ENVI Classic .roi files, which my colleagues use a lot.
I can ...
- 304
9
votes
1
answer
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Reprojected MODIS NDVI has range from -32768 to 32767, expected -1 to 1
I'm new to StackExchange and to remote sensing. I am working with MOD13Q1 250m 16-day MVCs. My goal is to use NDVI time-series to classify cropping pattern and crop type, then link this data to ...
- 759
9
votes
2
answers
16k
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How to repair topology of a shapefile?
I performed an object-based image analysis using ENVI EX, and each of the classified features were exported as a shapefile. I transferred those shapefiles into ArcMap 10, and tried to intersect them ...
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9
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2
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Landsat8 DN to TOA Reflectance (minus values)
I'm learning how to perform atmospheric correction manually, hence not using the automated methods available in ENVI
metadata (band 1) for my Landsat 8 scene is as follows;
RADIANCE_MULT_BAND_1 = 1....
- 93
8
votes
1
answer
2k
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Rotate ENVI hyperspectral imagery with GDAL
I am developing an application with the GDAL library to combine georeferenced raster hyperspectral imagery in ENVI format from NASA's Airborne Visual/Infrared Imaging Spectrometer (AVIRIS) with other ...
8
votes
1
answer
443
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Opening MOD17A3 in ENVI so it is properly georeferenced?
I am using ENVI 5.1 on Windows 8. I am trying to open a MOD17A3 (MODIS Net Primary Productivity standard product - L4) .hdf file which I downloaded from the USGS website. I am still a beginner at ENVI,...
- 89
8
votes
1
answer
331
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Phenological event extraction in IDL
I’m doing phenological study using a threshold method in IDL. I have a twelve-band image in 2005 (format is in .tiff not ENVI format). Twelve-band means that monthly images (Jan to Dec) have been ...
- 81
6
votes
4
answers
482
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Transform raster donuts to circles
Let's assume I have a raster image consisting of 0's and several donut-shaped rings of 1's. This raster could for example be the result of classifying a satellite image with ponds and lakes in it into ...
- 1,035
6
votes
1
answer
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How to remove clouds in High resolution Imagery(.5 mGeoeye)
I have imagery with high resolution .5m, large parts covered with clouds, so it's obscure many urban areas.
How can I remove the clouds?
- 1,103
6
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5
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Fixing Landsat 7 SLC-off in ENVI
I have a couple of Landsat 7 images and they all have striping as a result of the SLC failure. Does anyone have any suggestions as to how to destripe the image using ENVI? I plan to use these images ...
- 165
6
votes
2
answers
379
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How to remove vehicles from an aerial photograph
I have an aerial photograph of an area. The image includes visible traffic signs and vehicles. How can I remove the vehicles from the image? Is it possible to do so in software like Erdas or Envi ...
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5
votes
3
answers
893
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ENVI EX reviews?
Does anyone have a review of ENVI EX? I am wondering how well the Feature Extraction and Image Classification workflows function.
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5
votes
2
answers
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Replacing Raster Values in Ras1 with Ras2
I have two rasters Ras1 and Ras2.
I want to change the Ras1.
In Ras1, there are few areas, lines, points I am interested having nodata cells and wrong data cells.(limited to interested areas only ...
- 814
5
votes
2
answers
509
views
Matching Landsat 8 with previous Landsat images
I am working with Landsat 8 in ENVI. My image's dimensions are 8921 x 13131. I need to apply a forest mask to this image with dimensions of 8805 x 12321. I try to resize an image, but it doesn't work. ...
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4
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Vector Machine Classification in ArcGIS
Is it possible to perform a vector machine classification of raster image using the ArcGIS software package. This supervised classification method is available in the ENVI software but not for ArcGIS.
...
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5
votes
1
answer
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Writing band names into header (ENVI file type) using GDAL?
I am writing numpy arrays out as ENVI images using gdal in python. Until today, I always accessed the header the hard way by reading in all lines, changing some information and writing it out again. ...
- 211
5
votes
1
answer
334
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Classifying different surfaces having almost similar Reflectance responses
I am using ENVI 5.3 to classify a Region of Interest clipped from Landsat 8 OLI. I have already performed calibration of my DNs by transforming it into Radiance and derived Reflectance image using ...
- 1,198
5
votes
1
answer
634
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Identifying pixels with sun glint in a satellite image (for atmospheric correction)
Wondering if anyone knows a way (perhaps objective) to identify pixels that are infected with sun glint in an image. I'm using Hedley's 2005 approach in a python to deglint my image but this approach ...
- 505
5
votes
2
answers
1k
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Applying pixel reliability mask to time series MOD13Q1
I am working with a 23-band GEOTiff in which each band is a 16-day MVC MODIS NDVI image. The MODIS .hdfs include a "pixel reliability" image with the following values:
[-1]: Fill/No Data-Not ...
- 759
5
votes
2
answers
402
views
ENVI to map composition
I'd like to print out 6 images in a single page. How can I do this using map composition tools in ENVI (6 images are year-to-year dynamic images with the same size and the same geo-referencing)?
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4
votes
2
answers
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Converting *.tif file into headerless (flat) binary file?
I am using NDVI files (value range -1 to +1) created from Landsat CDR images to produce a timeseries in TIMESAT software.
My .tif file has following characteristics.
File type TIFF,Data Type ...
- 61
4
votes
3
answers
8k
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How to create animation from raster data?
I have some NDVI and precipitation/temperature images at the monthly time step from Jan, 2005 to Dec, 2008.
I need to create animation image to show the temporal change.
How can I do this?
Is it ...
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4
votes
2
answers
3k
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Calculating Net Primary Production (NPP)?
When I calculate Net primary production (NPP) for a local scale, what kind of software should I use?
I always use ENVI, ERDAS IMAGINE, ArcGIS for Desktop and IDRISI.
Is it possible to use these ...
- 579
4
votes
3
answers
3k
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Matching colours in already mosaiced single image? [closed]
I have an already mosaiced image for a large area. I need to match colours in this single image. I do not have each image separately. I just have this large single image downloaded from GLS. How can I ...
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4
votes
1
answer
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How to extract single band from multi-band radiometry raster using R?
I am having trouble extracting single band from multiple multi-band raster. I have no problem doing it on single raster file.
Is there a way to loop through all the raster images to extract a single ...
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4
votes
3
answers
2k
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Merging georeferenced images that have overlapping information?
Having trouble to mosaic two overlapping .tif files. I need to merge these two images together into one resampled raster image. Unfortunately I cannot do this with my ability and resource available to ...
- 157
4
votes
1
answer
4k
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How to use the same ROI for multiple LANDSAT images in ENVI?
Suppose that I have 3 landsat images with the same datum ( WGS-84 ) and projection system ( UTM, Zone 39N ) as follows:
TM LANDSAT 5 image for July 1987
ETM+ LANDSAT 7 image for July 2001
OLI_TIRS ...
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4
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1
answer
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Is LANDSAT 8 Resolution too low for coastline difference measurement?
I recently extracted coastlines (for my master thesis) for a Bangladesh region for the years 2013 and 2014. Regardless of the method I used, the distance between the 2 coastlines was always the same: ...
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2
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Digital Number (DN) on satellite imagery? [closed]
How would I know if any of the satellite imagery (Landsat, ASTER, Quickbird and so on) have DN or Digital Numbers such as integer or uninteger on its pixel. I download from the USGS EarthExplorer and ...
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4
votes
1
answer
6k
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How to read/write ENVI metadata using GDAL?
I am trying to use GDAL to read and write images in ENVI format (for example a .bsq file with an associated .hdr file). The GDAL Formats Info page states "Starting with GDAL 1.10, all ENVI header ...
- 3,996
4
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1
answer
383
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Differences in the longitude and latitude between a LiDAR DSM and an optical image
I've downloaded the UK's LiDAR elevation data (see below) in laz format for a specific region (Tewkesbury) from: http://environment.data.gov.uk/ds/survey#/download
From that, a DSM (Digital Surface ...
- 956
4
votes
1
answer
642
views
Why getting wrong NDVI values resulted from scaled reflectance in ArcMap?
I have made atmospheric corrections to my Landsat 8-OLI raster using 'ENVI FLAASH' having surface reflectance values scaled between 1-100.
In ArcGIS I am using simple expression to compute NDVI ...
- 1,198
4
votes
1
answer
815
views
Where are the "band names" of an ENVI file once it is imported in R?
I have a .dat file (ENVI format) with specific band names, as you can see in the snapshot.
I've imported this file in R, but I cannot find the band names in the R object.
The command
names(...
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4
votes
2
answers
2k
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ENVI raster file with nodata change to 0
I have a geotiff that I converted to a ENVI raster file with the following command:
gdal_translate -of ENVI srtm_05_08.tif data.bil
The geotiff has water values supposedly set to nodata. I am ...
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4
votes
1
answer
663
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Error reading envi file from zip using /vsizip and gdal in python
I am having an issue reading an ENVI binary file (with .hdr file) from a zip file using GDAL in Python and the /vsizip driver.
I know the ENVI file (binary and header) itself is fine, since when I ...
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3
votes
5
answers
4k
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Batch process to get single band image from stacked image using ArcGIS, ERDAS or ENVI?
Can you help me to extract a single band image from stacked multiband image. Totally, 260 image has been stacked. When I do to this, it will take a long time. So I'd like to know there is any batch ...
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3
votes
1
answer
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EVI and NDVI range value
I've used a Landsat 8 image for vegetation analysis in an urban area. I've got a large maximum number of EVI value as shown in this image:
Is this normal in calculating EVI and NDVI? Because I know ...
- 63
3
votes
3
answers
1k
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Extract values from raster based on points and pixels adjacent to the point
I have an issue. I have a set of points (n=~2000) and I would like to extract the pixel values from multiple rasters (a single-raster solution is also ok) for location of that point as well as that of ...
- 91
3
votes
3
answers
324
views
How to assign mean values from different windows sizes to point feature?
I have points overlaid on an elevation raster as shown below;
The aim is to get mean value of each point computed from 3x3 window size covering its immediate neighbouring pixels.
It will be ...
- 1,198
3
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4
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Some remote sensing tutorials [closed]
I could use some tutorials on remote sensing, but some books provided they are free, would be useful.
To be specific, tutorials on ERDAS Imagine, ENVI and other remote sensing software, general ...
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3
votes
1
answer
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MOD 35 Cloud Mask HDF in ENVI
I am having difficulty getting ERDAS or ENVI to correctly read and display cloud mask attributes from MOD 35 HDF files. They files are displayed as 0-255, whereas I expected some kind of code 0, 1, ...
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3
votes
2
answers
2k
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Reading MODIS L1B into ENVI
I am working with MODIS Terra (and simultaneous ASTER) Level 1B swath data using ENVI and am having one of these "this should be easy" questions about the most direct way to get to geo-referenced ...
- 1,246
3
votes
1
answer
500
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Creating ALOS PALSAR 1.0 level JAXA Orthorectified K & C Mosaic interferometry
JAXA is providing free access to PALSAR 50m Orthorectified K & C Mosaic.
The files are not in the typical PALSAR format. I'm looking for apps that can read and export this data.
Is it possible ...
- 432
3
votes
1
answer
901
views
How to extract impervious areas from Landsat data?
I'm working with multi-temporal datasets from Landsat (Landsat 8 & Landsat 7 & Landsat 5) and I tried to extract impervious areas, more exactly urban areas, but I can't obtained results very ...
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3
votes
2
answers
1k
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ENVI BIL file algorithm logic
I have a 6 band Landsat image, RGB and 3 NIF bands. As far as the Band Interleaved by Line (BIL) method goes, the resulting image should have, and I quote ENVI manual:
the first line of the first ...
- 8,556
3
votes
1
answer
413
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Planet filter file for ENVI atmospheric correction
I have 4 band Planet Scope multispectral imagery that I am trying to process in ENVI. It is the analytic data, so it is already radiometrically corrected. I have converted the .tif to a BIL, and ...
- 31
3
votes
1
answer
261
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MODIS L1B reprojection and mosaic problem
I have been using MODIS L1B file to retrieve water vapor content. However, my study area is exactly between the gap between two images,just like this:
I have tries ENVI MCTK extensions, HEG TOOLS, ...
- 69
3
votes
1
answer
1k
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Converting HDF file (MODIS product) in ArcGIS as correctly georeferenced raster by ENVI?
Which algorithm I should use in ENVI 5.2 to open the MODIS product (MOD13Q1 or MODIS/Terra Vegetation Indices 16-Day L3 Global 250m Grid SIN V006), given as HDF file to ArcGIS 10.5 as correctly ...
- 397
3
votes
1
answer
941
views
ENVI 5.0 Applying one ROI on various images
I'm comparing different classification methods (parallelepiped & max likehood) with ENVI 5.0 Classic. I'm supposed to use the same ROI from one image on various images and validate the ...
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