Collecting and interpreting information about the environment and the surface of the earth from a distance, primarily by sensing radiation that is naturally emitted or reflected by the earth's surface or from the atmosphere, or by sensing signals transmitted from a device and reflected back to it.

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3
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0answers
9 views

Classify image using segmentation analysis using QGIS and OrfeoToolbox

My first question on stackexchange (sorry for my english language)! I use stackexchange often to understand GIS principles and workflows. I wasn't able to find a answer. For this project we made a RGB ...
0
votes
0answers
8 views

Why rescaling disturbs Band Order of FLAASH derived Reflectance image?

I have derived Reflectance values (MS bands) by calibrating Landsat8 OLI using ENVI's FLAASH module. The outcome of the FLAASH derived Reflectance values are scaled by 10,000 (by default), The reason ...
1
vote
1answer
215 views

Maintaining spatial integrity of Matlab matrix with missing data

I am working with MODIS Terra imagery (MOD13Q1). I am currently trying to compute the autocorrelation structure of the pixels in an MODIS NDVI raster. The problem is that I have clipped the original ...
0
votes
1answer
31 views

What resolution will be able to show visible changes on a parcel of farm land? [on hold]

What resolution will be adequate (5m, 2.5m, etc) to show visible changes on a parcel of farm land? Each plot is typically the size of two football pitches. Details to detect: a) has the farm land ...
1
vote
1answer
45 views

Point otbApplication for python to the relevant OTB DLL's

I installed the latest OTB and Monteverdi on a Win 7 machine. Via osgeo4w I downloaded otbApplication for python, without any dependencies. Python, gdal, numpy scipy and so forth was custom build ...
-1
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0answers
16 views

Which Paid Satellite imaging services can provided scheduled image updates for specified areas [on hold]

Are there Satellite imaging Services that can provided scheduled image updates for specified areas? What resolutions are typically available from each? (please recommend). Area of interest: Northern ...
0
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0answers
11 views

Facing “unknown sensor error” in using Alos Polsar 2 (Geotiff format) at ENVI 5.3

For calculation of Radar Backscatter for Alos 2 (2015) whit Geotiff format via ENVI 5.3, I faced following error: "The target file does not appear to be a valid sensor type" The question is; how ...
0
votes
1answer
22 views

Layer stacking Sentinel 2 imagery

Is it possible to layer stack all 13 Sentinel 2 bands or can I only layer stack those that are the same resolution (so for example the blue, green red and NIR bands). I have a very large area of ...
3
votes
1answer
165 views

ICESat/GLAS coordinate system conversion

I have to import ICESat GLAS14 product data into ArcGIS. I managed to export into an ASCII file the binary GLAS data using NGAT tool, but the coordinates system are in an uncommon format ...
3
votes
0answers
26 views

How to classify difference 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 ...
2
votes
1answer
417 views

Python script for dark object subtraction on Landsat 8 Imagery

Does anyone know of any python scripts that will allow me to conduct such a process? I am limited to open source software and have minor experience in Python.
0
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0answers
12 views

Layer stacking many images using Python and Erdas Imagine Spatial Modeler

I have downloaded huge amounts of Sentinel 2 data to cover a large area of the Himalayas and need to layer stack each tile. I have decided to use Python to do this using the LayerStack tool from Erdas ...
1
vote
0answers
17 views

ModelBuilder Iterations and Data Storage

OK, so here's my situation. I have a large series of rasters divided into two categories, let's call it Type A & Type B, a pair for each of a few hundred date/time snapshots. The date/time for the ...
1
vote
3answers
55 views

What preprocessing is required when using Landsat for LULC?

Can anyone help me regarding the what kind of image pre-processing techniques should be used for the landsat images downloaded from http://earthexplorer.usgs.gov/ to create land-use land-cover (LULC) ...
4
votes
1answer
29 views

Where / How to download Sentinel 2 Images

I need Sentinel 2 imagery of Nigeria, I signed up in Copernicus Scihub but typing Nigeria into the text box no results appear. I must be doing something wrong, how can be possible that they do not ...
2
votes
0answers
12 views

Image sizes for VHR remote sensing image

I need to compare three or four different segmentation algorithms on very high spatial resolution remote sensing images, with a range between [0.31,1.00] meters/pixel. What image size could you ...
0
votes
2answers
37 views

Removing black background in ENVI

I am trying to compare two DEM products ASTER and SRTM v.3, but the ASTER has the black background which i think will interfere with my analysis. I don't have access to ArcGIS where I can do this ...
1
vote
0answers
7 views

Issues with using FLAASH on GeoEye data

I am trying to carry out a FLAASH atmospheric correction on radiometricaly corrected GeoEye-1 spatial image (working within ENVI). I am geting the wrong results from my FLAASH correction and belive ...
1
vote
2answers
188 views

Landsat 8 OLI Tasseled Cap Transformation Calculation ArcGIS 10.3

I need to calculate the TCT greenness for Landsat 8 OLI imagery and having a hard time finding a tool. All the python scripts I have found do not work and I am not experienced with Python at all. ...
1
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0answers
12 views

Spectral classification for crops

I'd like to do a classification using a multispectral raster (1 Blue 475, 2 Green 560, 3 Red 668, 4 Red Edge 717, 5 Near IR 840). I'd like to classify the crops (kiwi plants). I tried a few ...
14
votes
9answers
917 views

What is the best/easiest way to obtain temporal Landsat imagery?

It's been awhile since I've dealt with optical imagery. I need to perform a land cover classification at mid-latitudes using several LANDSAT scenes. I've noticed that some online tools are still ...
2
votes
0answers
23 views

Calibration error for Sentinel 1 image in SNAP toolbox

I am working with a Sentinel 1 SLC IW image (VV+VH) and trying to calibrate the data in the SNAP toolbox. However, it keeps returning the error "cannot construct data buffer" Does anyone have any ...
2
votes
2answers
442 views

Classification, Change detection and NDVI Using (landsat2 MSS), (landsat5 TM), (Landsat7 ETM+) and (Landsat8 OLI)

I have 5 Landsat images for the same study area. One of them in 1975 (Landsat 2 MSS), two in 1985 and 1995 (Landsat 5 TM) and one in 2005 (Landsat 7 ETM+) and the last one in 2014 (Landsat8 OLI). I ...
19
votes
3answers
4k views

How to produce high-resolution DEMs from new Sentinel-1 data?

This is a general question relating to the new Sentinel-1 data. I'm interested in the potential for using this data to create high resolution DEMs in GIS (I use QGIS), to investigate archaeological ...
3
votes
1answer
418 views

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 ...
2
votes
3answers
585 views

Tasseled Cap Transformation Rapid Eye

I want to do tasseled cap transformation on rapid eye data. the main question would be about the parameters which are used. Somebody has a suggestion? A short update concerning this attempt to ...
2
votes
1answer
627 views

Enhanced vegetation index using ENVI 4.7 bandmath

I computed Enhanced Vegetation Index using band math in ENVI 4.7 software. The expression used was: 2.5*((float(b1)- float(b2))/(float(b1)+ (6*float(b2)) +(7.5* float(b3)))) BYTSCL(float(b1), min = ...
0
votes
0answers
19 views

Spatial Resolution (Scanning Precision)

I am using Landsat_7 image and details is pasted below: - Date of acquisition: January 2001 -Pixel size: 25 m -Spectral bands:  Band 1: Blue 0.45-0.52 µm  Band 2: Green 0.52-0.61 µm  Band 3: Red ...
0
votes
0answers
10 views

MODIS MCD43A3 albedo product: good quality observation and fill value at the same time?

I’m using the MODIS MCD43A3 albedo product on one of my projects. I only used the good-quality values determined based on the BRDF_Albedo_Quality band recorded in the associated MCD43A2 product. ...
0
votes
1answer
53 views

Remote sensing accuracy assessment - McNemar`s Test

I would like to know how you determine the f12, f21 parameters for use in the McNemar`s test when for example I have two confusion matrices such as below: (where f12 = number of cells misclassified ...
2
votes
1answer
228 views

applying savitzky golay filter to modis ndvi data

I want to smooth the ndvi MODIS 16 bit integer data .tif for LULC classification . i have timesat 3.1 software on windows but i don't how to apply the SG filter . i am not that good in programming . i ...
4
votes
0answers
17 views

Is there a way to use the GDAL C++ API to find areas of overlap between two SAR images?

I have a bunch of SAR images (about 1 GB each) on which i need to do some image processing. Each image is georeferenced and there is significant overlap between each pair of images in the set ie. one ...
7
votes
3answers
255 views

Sentinel-2 projection shift

I recently observe a shift in the geographic projection of Sentinel 2 data. Please see the screenshots below for clarification (Granule T33UXP, Band 8 only). The first image was taken on 20160314, the ...
0
votes
0answers
28 views

Using MODTRAN 5?

I am trying to use MODTRAN 5 for atmospheric correction as well as retrieving atmospheric transmittance. Could anyone please help me with the basic MODTRAN 5? There's no video tutorial/guideline on ...
3
votes
2answers
429 views

Opening image files with Sentinel 2 toolbox

Anyone worked with the Sentinel-2 toolbox/SNAP? It doesn't support sentine-2 data to be opened directly. I tried opening .safe, .zip and .xml files.
0
votes
1answer
30 views

Landsat 8 cloud detection without band 9

What is the best possible way to create a cloud mask of a Landsat 8 scene without using band 9? I think the best way will be to determine the cloud cover by thresholding in the Panchromatic band and ...
1
vote
3answers
99 views

What are the white grids at 9.6953038715817,98.576672019046 in Google Maps?

A friend asked me to help interpret the white grids at 9.6953038715817,98.576672019046 in Google Maps. In satellite image the grids are connected to rivers flowing into the Andaman sea. Most of the ...
4
votes
1answer
253 views

How to compute NDSI in ArcGIS for Desktop?

How do I compute a Normalized Difference Snow Index (NDSI) in ArcGIS's Raster Calculator? I have a Landsat 8 scene (hdf4 format) that contains derived surface reflectance band-by-band. Each band is a ...
7
votes
2answers
12k views

Download new SRTM 30 meters

I read about the new version of the digital elevation model at 30 meters (SRTM 30 meters), but I can not find from were I can download it. some sources: ...
3
votes
1answer
53 views

Temporal spectral analysis in order to differentiate agricultural/croplands from natural/semi-natural grasslands using remotely sensed data

I am working on a critically endangered bustard species in India (Houbaropsis bengalensis). I need to prepare a land cover map of its 'suitable' grassland habitat across its distributional range. I ...
0
votes
1answer
37 views

Comparing SAR and SRTM, Which data source can produce relatively accurate DEM?

How much accuracy could we can expect from producing DEM from SAR using InSAR techniques as compare to available SRTM 1ArcSec data? Specifically in view of the available Sentinel-1 datasets? Any ...
1
vote
2answers
44 views

Identifying bands of satellite images qgis

I have a series of satellite images and am not sure which satellite took them. I know there are 8 bands but not which band relates to which spectral color. Here is the metadata of one image : Driver ...
0
votes
0answers
14 views

Proper Tool for Creating a 3x3 Window for Cluster Sampling in Accuracy Assessment?

I'm using a cluster sampling scheme for an accuracy assessment of the 2011 National Land Cover Dataset (spatial res of 30m). I'm using Google Earth Pro for my reference data spatial res of 15m). So ...
1
vote
1answer
238 views

Error in downloading MODIS image using R script

I am trying to download "MOD13A3" MODIS image using R script (http://r-gis.net/?q=ModisDownload) but each time it's ending in error. How to make it work ? ...
3
votes
0answers
12 views

How to snap vectors to vertices for ROI delineation

I am trying to manually extract a set of ROIs in ENVI 5.0. However, I can't seem to successfully line up the vector to be flush with the boundary of the pixels, which means I don't have fine-tune ...
-1
votes
0answers
10 views

use landsat7 to retrieve LST

I'm doing spatial and temporal change analyze of thermal environment. Can I use Landsat7 ETM+ data to retrieve land surface temperature (after gapfill)? I was wondering whether the quality of ...
0
votes
1answer
33 views

Creating a Grid For Raster When Measuring Land Cover In Accuracy Assessments

I am assessing the accuracy for the 2011 National Land Cover Map (NLCD). Each pixel for the NLCD measures 30m x 30m. For my reference data, I'm using two sources: 1) Google Earth (~20 m ...
0
votes
0answers
26 views

How to set background value as transparent in ENVI 5

How might I set the nodata/background value as transparent in ENVI 5.0? I know that I can edit the header of the file and set the "ignore value" field, which I tried (setting the field to ...
1
vote
1answer
30 views

Satellite data to watch atmosphere and ionosphere

Which bandwidths are best suited to watch atmosphere and ionosphere of a region? And what are the sources (satellite sensors/names etc)? Any suggestion would definitely help me to narrow down my ...
2
votes
2answers
44 views

Pansharpening influence on analysis

Using as an example Landsat 8 bands: Does pansharpening band enhace only visible range and therefore can I use it only for analysis connected with visible spectrum? Or I can pansharpen every possible ...