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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1answer
11 views

Methodology for Image Classification (beginner) [on hold]

I'm a beginner with remote sensing and have the task of creating a land use/land cover map of a region in India from IRS imagery. I've never performed an image classification before, although I do ...
1
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1answer
12 views

Are my reflectance values of bands in range and what does DRA in GIS 10.1 do to bands?

I have done the TOA correction to red and near infrared bands using raster calulator then after i calculated NDVI from lansat 8 image. but the NDVI range came as : upper range=184 and lower ...
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0answers
27 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
20 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 ...
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1answer
20 views

“First” and “Last” from Global Forest Change [on hold]

What are the "first" and "last" rasters provided by the Global Forest Change data set?
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0answers
19 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
29 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
12 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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0answers
16 views

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

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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1answer
31 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
33 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
18 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
14 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 ...
0
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1answer
29 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
votes
2answers
43 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
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 ...
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3answers
60 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
14 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
40 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
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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 ...
2
votes
0answers
30 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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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 ...
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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. ...
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1answer
55 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
votes
3answers
262 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
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1answer
33 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
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 ...
3
votes
1answer
55 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
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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
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2answers
47 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
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 ...
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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 ...
0
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1answer
34 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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0answers
27 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
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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 ...
4
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0answers
37 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
vote
3answers
183 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
37 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: ...
0
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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
votes
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
votes
1answer
77 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 ...
1
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2answers
40 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
votes
1answer
33 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 ...
1
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0answers
36 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 ...
1
vote
1answer
47 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 ...
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0answers
29 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 ...
1
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0answers
26 views

Connect a photo and a DEM using landscape features

I'm helping with an image retake study in Alaska, we have historical (up to 100 years old) photos of the landscape (with lat/long) and we'll be retaking photos this year at the same locations. The ...
0
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0answers
34 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?