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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30 views

Free satellite images for academic purposes [duplicate]

Since the Landsat mission opened it's archive a lot of great scientific studies have been produced in the field of Remote Sensing. The Sentinel imagery from ESA is also thought to be open access ones ...
2
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1answer
48 views

Imagery Band order for Natural and False color imagery

I have an image which has had its band ordering rearranged, giving it a weird false color. I wanted to change it back to a natural color, so I used GDAL and through trial and error got the bands re-...
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1answer
29 views

“First” and “Last” from Global Forest Change [closed]

What are the "first" and "last" rasters provided by the Global Forest Change data set?
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57 views

How to mosaic two ladsat images when they have different reflectance distribution value

I have two adjacent landsat-8 images from two different time, April and October. They have different reflectance value. While mosaicing these two does not seem to have matching histogram. I tried by ...
3
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0answers
114 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 ...
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0answers
44 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 ...
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1answer
37 views

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

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 ...
3
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0answers
54 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
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0answers
24 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 ...
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0answers
65 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 ...
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1answer
169 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 ...
2
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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 ...
4
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3answers
167 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 ...
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0answers
21 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 ...
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3answers
101 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) ...
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0answers
25 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 ...
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2answers
87 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 ...
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0answers
12 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 ...
2
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0answers
80 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 ...
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25 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....
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0answers
17 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. ...
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1answer
104 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 ...
7
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3answers
309 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 ...
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2answers
56 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 ...
4
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0answers
27 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 ...
3
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1answer
74 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 ...
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1answer
55 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 ...
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2answers
59 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 ...
3
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0answers
16 views

Snapping 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 ...
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0answers
16 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 ...
0
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1answer
47 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 ...
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54 views

Setting background value 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 -3....
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1answer
32 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
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2answers
53 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 ...
4
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0answers
41 views

Ice type differentiation using satellite data

I would like to classify glacial area by categories of snow (if there is) and ice, but what's most important: between old ice and fresh ice. They have different properties that are possible to ...
1
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3answers
209 views

Classifying individual trees from labelled LiDAR point cloud [duplicate]

I have a classified point cloud for an area of 250*250 square meter, with 1 meter resolution. It has a 5 lakhs points with an average point density of 9 (means around 9 points within a pixel). I ...
2
votes
1answer
49 views

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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0answers
8 views

How to correct for the shift in AVHRR data?

I just started using the AVHRR 1km global dataset (http://edc2.usgs.gov/1km/1kmhomepage.php) because of a need to examine the long-term forest disturbance history. After acquiring the imagery, I ...
4
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1answer
25 views

Defining city name by using KMZ files

We have KMZ files of different satellite images. We want to check which cities these satellite images belong to. Is there a way to do it automaticly? Like a tool in ArcGIS or QGIS or whatever?
6
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1answer
163 views

Difference between Landsat 7 and Landsat 8 TOA reflectance computation

In section 3.1 of this article it is explained how the Top of Atmosphere Reflectance for Landsat 7 and Landsat 8 are computed. The equation for Landsat 8 is not mentioned explicitly, but can be found ...
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2answers
51 views

Modis MOD11A1 band math expression

I am trying to calculate the temperature of MOD11A1 and I can't find the expression of band math. How the expression temp < 273 could be written at band math?
3
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1answer
45 views

Reflectance values from WorldView-1 images?

Most of the informations on WorldView images are related to the second and third version of the satellite. I own a WorldView-1 image (the black and white one) and I really need to find the reflectance ...
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0answers
57 views

Why are Landsat-8 derived NDVI values higher than SAVI values?

I have calculated NDVI and SAVI vegetation indices for a landsat-8 image. I am unexpectedly getting higher values for the NDVI than SAVI. What may be causing these unusual results? NDVI=0.46 SAVI=0....
1
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1answer
75 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 ...
0
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0answers
47 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 ...
2
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1answer
47 views

Georeferencing an oblique angle photograph in repeat-photograph studies

Backround: Aerial photography and remote sensing can be used to measure current land cover and recent land use change. However, these technologies are fairly recent and therefore time series are ...
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0answers
43 views

How to calculate vertical exaggeration in stereoscopy?

How can I calculate the 'seen' vertical exaggeration of my set of orthophotos, when working with a stereoscope? What factors determine it?
2
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2answers
177 views

How to calculate LAI (Leaf Area Index) using Remote Sensing? [closed]

I am new in remote sensing, and I would like to ask the community what are some good methods to calculate the Leaf Area Index (LAI) using Remote Sensing Data, for agriculture mostly applications.
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0answers
44 views

How to extract coherence and covariance matrices of TerraSAR-X data?

I have obtained quad-polarized level 1b TerraSAR-X data from DLR. When I tried to read the data using PolSARpro, I understood that it is only capable of reading SSC format But my data is in MGD (...
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0answers
30 views

How can I find pixel spacing in azimuth and range and look angle from envi sarscape?

I have a quad-pol ALOS-PALSAR dataset, which I have read using Envi SarScape. Now I find to read the header or where the following information is written: pixel spacing azimuth pixel spacing slant ...