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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15 views

PolSAR pro v4.2 cannot read the data file for UAVSAR, why? [on hold]

I have 6 UAVSAR data files: as suggested by the UAVSAR PolSAR data format, the files are OK. In order to read them by PolSAR pro v4.2, I set the environment: and then in the Import ...
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0answers
29 views

Format of SAR images

What is the format in which SAR images are stored? By format I mean when a SAR captures an image, it gets saved in what format? jpg? png? tiff? or there is some other special format? Is there a ...
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0answers
26 views

Change detection in multi-temporal SAR images [on hold]

I would like to know what are the state of the art techniques, used for performing change detection in multi temporal SAR images. The simplest of techniques are the algebraic ones,like image ...
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0answers
17 views

How to get multi-temporal InSAR data?

I am very much new to InSAR data. At the moment, i'm stuck at this website https://ursa.asfdaac.alaska.edu. Just wanna know, is it possible to get multi-temporal InSAR data for a particular region ...
3
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1answer
37 views

what does it mean to store cross products in SAR product data file?

I'm reading the UAVSAR data format For definition of two types of file we have: MLC files (.mlc): calibrated multi-looked cross products, floating point format, three files8 bytes per pixel, ...
2
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1answer
45 views

What is multilooking?

Today I found a video on youtube for multilooking the data with NEST (Next ESA SAR Toolbox) and it seems that it produces square pixel out of rectangular SAR pixels. Does it operate as simply as ...
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0answers
80 views
+50

Deciding variables for image classification?

The results of an image classification may vary A LOT depending on the variables you use from the beginning. Number of classes, minimum class size, sample interval, atmospheric corrections, ...
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1answer
20 views

aerosol optical depth

i want to extract aerosol optical depth on land using modis it seems like I need a value from one of these parameters between Corrected_Optical_Depth_Land and Corrected_Optical_Depth_Land_wav2pl but ...
4
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1answer
68 views

Free open satellite or other remote sensing data for night time?

I usually work with daytime satellite images to do some image classification (mostly Landsat data from the USGS EarthExplorer). Right now I'd like to check at some night time images to work on city ...
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1answer
38 views

Calculating NDWI in Erdas IMAGINE 2014

I'm using MOD09GQ product of MODIS to calculate vegetation indices in Erdas 2014, and I was able to extract NDVI using Erdas Model Builder. What is the formula I should use in model builder for ...
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0answers
9 views

Problem using ENVI/IDL ENVITask('BuildBandStack')

I am trying to stack 2 bands together from 2 different landsat images using ENVITask('BuildBandStack'). These are landsat images from two different years, and Band 1 in both years. When I run my code ...
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0answers
31 views

Hard wood tree and Soft wood(shrubs) Vegetation Differentiaton

How I Differentiate Hard wood tree (like Mango, Sal) and Soft wood(shrubs like reed) Vegetation using Multispectral or Hyperspectral Image? I have TM, ETM, OLI, Hyperion, Aster Image and ERDAS 2011, ...
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1answer
47 views

Is there any packages to download landsat image by shapefile boundary in R or python? [closed]

I want to find a package which can automatically download images within a predefined administration boundary (shapefile format). Does anyone know a package can conduct or simplify the process?
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1answer
63 views

Why is azimuth resolution worse than range resolution in Sentinel1 (SAR) [duplicate]

Why is the azimuth resolution in Sentinel (SAR sensor) worse than the range resolution? The table in this link gives the resolution for SLC products aquired in the different aquisition modes. In ...
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1answer
35 views

Is there any comprehensive book or online instruction on image segmentation techniques?

I'm looking for a source to learn theoretical basis of image segmentation techniques thoroughly. The desirable book, or other kinds of source you may know, should cover the techniques that are more ...
4
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1answer
77 views

Determining the best month for discriminating between different vegetation types?

I ordered and downloaded several (Surface Reflectance) Landsat 5-8 images from USGS Earth Explorer with the purpose of choosing a few of them to calculate some Vegetation Indices for each (NDVI, SAVI, ...
3
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2answers
68 views

Why does the resolution decrease with increasing incidence angle in the Sentinel-1 SAR sattelite

On this link (Sentinel1 webpage for a SLC product), the resolution is written as a range from the highest corresponding to low incidence angle, to the lowest resolution corresponding to high incidence ...
2
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1answer
77 views

Why does the peak of a mountain appear bright on Radar images

Why does the top of a mountain appear bright on a SAR (radar) image. I know that the peak of a mountain is subject to a layover effect, thus appearing closer on the radar image than the bottom part of ...
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0answers
16 views

Is this terminology I'm using is suitable for the field spatial analysis of time series?

I'm going to apply time series concepts to an satellite image, but instead of using time data located on the 'X' axis, I want to use spatial variations on that axis. In addition, the 'Y' axis keeps ...
2
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1answer
48 views

Difference between a spectroradiometer and multispectral sensor

Let's take as an example of a spectroradiometer MODIS, and as an example of a multispectral sensor the Landsat8 (OLI). What is the difference between these two sensors? Should we compare a ...
1
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1answer
31 views

Does satellite imagery have a unique azimuth for each of its spectral bands?

Does satellite imagery have a unique azimuth for each of its spectral bands? Is it right to say that if a sensor has 8 spectral bands, then it may have 8 different azimuth angle?
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0answers
35 views

Enhancing/smoothing Landsat 8 image using ArcGIS Online?

I understand that Landsat 8 is 30m resolution, but is there any technique that can be used to smooth/enhance the NDVI or Agriculture Landsat layers in an ArcGIS Online (AGOL) web map? I have adjusted ...
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1answer
47 views

Extracting Data from Raster based on Aspect Raster file

I have 2 rasters, ones shows aspect and another shows date of snow thaw. I want to extract the date of snow melt based on values from the aspect raster. For example I want all the snow thaw dates from ...
2
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0answers
24 views

Important to perform atmospheric correction when attempting to identify coral reefs?

I want to identify coral reefs using multi-temporal Landsat data and Lyzenga's Transformation method. In relation to pre-processing the image, should atmospheric correction be done or not? If not, ...
2
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1answer
53 views

Can a satellite go over the same area in different passes overtime

Can a sun-synchronous satellite (let's consider Sentinel-1) go over the same place, one time in an ascending pass and the next time (or few times after) in a descending pass?
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0answers
27 views

What does “Information [18]: Select at least one signature” in the semi automatic classification plugin mean?

I am using the semi automatic classification plug in to classify vegetation and water in a satellite image. I create training shp and signature list. When i hit "classification preview" it gives me ...
3
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1answer
59 views

Reading Synthetic Aperture Radar raster images using python

Is it possible to read and modify Synthetic Aperture Radar raster images using python? gdal is not able to understand their Type which is Binary (application/octet-stream). One can find sample radar ...
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0answers
19 views

What's the relationship between visibility and reflectance?

I'm having a problem with the atmospheric correction of remote sensing images. Until now I believed that increasing the visibility (or decreasing AOD) resulted in an increase in reflectance but now ...
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0answers
21 views

Geometric correction using topographic maps?

I am researching LULC change detection using Landsat 7 etm + image in 2000 and Landsat 8 image in 2014. Both are L1T images. Do I need to do geometric correction using topographic map for my study ...
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0answers
49 views

DEM input problem using ARCSI Landsat 8 batch processing

I'm trying to use ARCSI in Linux to process a batch of Landsat 8 images. I'm using the arcsibuildcmdslist.py to build the arcsi.py final command. I'm having problems in the input DEM ...
2
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1answer
49 views

Get resolution and whether right/left looking from sentinel metadata

Is it possible in Sentinel hub products to know the resolution of the product and whether the SAR was right or left looking at the scene? I know that it's possible to know if the SAR was operating in ...
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0answers
65 views

What kind of raster mosaicking to use in land cover analysis

I have to mosaic two rasters (Landsat ETM+ scenes) to one single image and then analyse its land cover. Which option to use to avoid seeing a distinct line in the place where two different ...
2
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1answer
70 views

Is atmospheric correction necessary when working with multi-spectral indexes?

When you are working with Landsat Level 1 data and calculate indexes, e.g. NDVI, NDBI, SAVI ..., do you calculate them using raw data (pixel DN value), or atmospherically corrected data (surface ...
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0answers
18 views

Change detection between two Landsat scenes? [duplicate]

I want to do time series analysis and find change in NDVI. I have rasters where each pixel is represented by some value at a time. Also I have same thing but represented by points. And I would like ...
2
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2answers
91 views

Raster image thresholding using python

I would appreciate if someone could guide me for applying thresholding technique to input raster image using Python. I intend to extract impervious surfaces from a high resolution raster such as ...
2
votes
2answers
122 views

land Use land cover classification

I am working on Land Use/Land Cover Classification of the Hindon river(India) watershed extracted using Aster DEM. Landsat 8 scenes had been used and mosaicked for the required AOI using the Watershed ...
2
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2answers
204 views

image segmentation of RGB image by K means clustering in python

I want to segment RGB images for land cover using k means clustering in such a fashion that the different regions of the image are marked by different colors and if possible boundaries are created ...
0
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1answer
35 views

Semi Automated Classification plugin (QGIS) error when trying to create ROI

When I try to create a new ROI through Semi-Automated Classification plugin (SCP) for QGIS, I keep getting a message saying: "It appears that SciPy is not correctly installed. Please, see this page ...
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0answers
51 views

NDVI calculation using ArcGIS 10.1

i have to derive NDVI from Landsat 8 image.. I used the following equation from landsat website with band 5 and band 4 using ArcGIS 10.1 Conversion to TOA Radiance OLI and TIRS band data can be ...
2
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2answers
147 views

How to atmospherically correct Landsat 8 data?

What is a simple way to atmospherically correct Landsat 8 data using Erdas 9.3 or ArcGIS 9.3?
2
votes
1answer
45 views

Landsat Surface Reflectancce product Python packages

I have to work with numerous Landsat surface reflectance product that I downloaded from http://landsat.usgs.gov/CDR_LSR.php. The product comes with a QA data with information on clouds and shadows ...
3
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0answers
18 views

Should Endmembers be Normalized for Linear Unmixing?

In biological spectral microscopy, the standard in the field is to use normalized endmembers in linear unmixing algorithms. In most cases, the endmembers are normalized to the maximum value. I have ...
0
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1answer
23 views

How do you digitize an ROI in envi 5.2?

Is there a way to digitize an ROI in ENVI 5.2 that is larger than the area shown in the viewer? I'm setting up labs for an intro to RS class, and the next step is to subset the image to get rid of ...
3
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0answers
66 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 ...
2
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0answers
38 views

Which preprocessing comes first for pansharpened imagery- atmospheric correction or orthorectification?

For pansharpened imagery, what preprocessing method to do first- is it atmospheric correction or orthorectification? From my readings, it seems the former but the rational polynomial coefficients or ...
3
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0answers
61 views

From Landsat spectral radiance (W/m2*sr*µm) to Global horizontal irradiance (W/m2) for mere mortals

We are working in a solar energy project to locate potential sites for solar panel farms. We are using the Landsat 7 panchromatic band to derive radiance with GRASS using i.landsat.toar (W/m2*sr*µm ...
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1answer
27 views

comparison of atmopsheric correction methods

I have noticed that dos methods for atmospheric corrections are in the section of radiometric correction (i.toar) on grass gis.Does that means that dos is a method doing radiometric and atmospheric ...
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1answer
121 views

Performing image segmentation in QGIS?

I have been trying to learn to work with QGIS (open-source GIS software) through some tutorials available online for classification of image for land cover. These tutorials used a dataset from Landsat ...
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0answers
43 views

Image formats to use for land cover classification in Python? [duplicate]

I am supposed to classify images for different land covers or land uses in Python. I read somewhere that the spectral module of Python is required to do the processing of Hyperspectral image data. ...
0
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0answers
60 views

Calculating climatological albedo using MODIS satellite images?

My question is based on the paper Using NOAA AVHRR and SPOT VGT data to estimate surface parameters: application to a mesoscale meteorological model. The authors have calculated albedo, surface ...