Questions tagged [remote-sensing]

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
316 views

How to decide possible areas for water retention using lidar

I have lidar imagery for a watershed and am trying to process it so that a landowner know if they can hold water on their property or where they can hole the water (this is the more important part). I'...
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How to perform enhancement operations on an satellite imagery in QGIS?

I am a new user of QGIS please suggest how to perform image enhancement operations on an satellite imagery like ratioing, contrast stretching, edge engancement, filtering etc. in QGIS?
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How to download large subsets of USDA NAIP imagery from Box.com?

The US Department of Agriculture’s Geospatial Data Gateway states, ‘As of April 21, 2017 the NAIP datasets are only available through the "NAIP Download" option on the home page and are no longer be ...
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How to get the wavelength values of bands from hyperspectral image?

I am trying to open and read a hyperspectral image using GDAL like below. So after reading the data like this : data = gdal.Open( filename ) then I can see the x, y, dim information of the dataset :...
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1answer
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Imagery Database/Metadata Store

I'm a Remote Sensing PhD student, and as such I have a large number of satellite images that I'm working with. I'm starting to fail to keep track of them all and I have a lot of metadata that I want ...
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1answer
807 views

How to produce a vegetation stress map utilizing the spectral blue shift of the red edge?

I am interested in mapping vegetation stress utilizing the blue shift to the red edge phenomenon in remote sensing. The figure below shows the expected change in reflectance of green leaves under ...
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4answers
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Seeking alternative to ERDAS Imagine? [closed]

I am having trouble with the ArcGIS 10.1 and ERDAS Imagine 9.2 license conflict. From what I found out it isn't that rare, but I do not understand why there such a conflict in the first place. ...
6
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2answers
922 views

Disaggregating aggregate GIS data using remote sensing

I haven't really done much with remote sensing imagery. I have census data for an area, and a TIFF raster image of the area. I'm sure this is possible, is there a simple way to disaggregate the ...
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Are there Python packages for Landsat 8 processing?

While there are a number of python projects for MODIS acquisition and processing (pyModis and get_modis), I have yet to encounter a toolset for automating Landsat 8 processing in Python. There's ...
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2answers
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Open source solutions for Landsat-8 mosaicing and correction?

I am familiar with the major commercial remote sensing packages (ENVI, IDRISI ERDAS, etc), but I haven't previously had the opportunity to utilize open-source solutions. I have a several new Landsat-...
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2answers
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Landsat in ArcGIS

I need to learn how to download, import and compose Landsat 8 in ArcGIS for natural colors (preferably in a GeoTIFF format). I have tried on my own but it seems that I am doing something wrong... ...
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2answers
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Open Source Remote Sensing vs eCognition, ERDAS etc Is it worth it? [closed]

What, if any, would be the main benefit of using a commercial tool like eCognition (in particular) or ERDAS as opposed to something like Orfeo Toolbox or OpenCV? (Feel free to suggest other open ...
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1answer
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Radiometric calibration of Sentinel-2 products

How can I calibrate Sentinel-2 products, to extract the reflectance? I've downloaded few Sentinel-2 products from https://scihub.copernicus.eu/s2/#/home, and opened them with SNAP but its radiometric ...
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4answers
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How to filter LiDAR data by scan angle?

I am looking to filter LiDAR data (.las format) by scan angle specifications (e.g. keep all points < 15). From a basic Google search, it appears that the libLAS library has the ability to filter by ...
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1answer
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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?
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3answers
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Removing cloud from Sentinel 2A imagery?

I would like to use sentinel 2A imagery to look at canopy cover in Northern Vietnam. The only problem is that ALL the recent images have large amounts of cloud in the area I want to look at. Is it ...
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3answers
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Is there a FTP to get Landsat images?

I need to automatically fetch Landsat images and for that it would be handy to access a ftp with images available. Does such ftp exist? Can I access it? Ultimately I want to get cloudless images.
6
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1answer
248 views

Which NIR bandwidth is suitable to Calculate NDVI?

Often we encounter multi-spectral and hyper-spectral sensors offering multiple NIR bands. For instance, the WorldView 3 sensor has 8 MS bands, out of them, two bands fall within NIR region. Near-IR1: ...
6
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1answer
254 views

How to know which satellite took the image?

I am having trouble finding which satellite took the images I have. Most are from digital globe. I read through the metadata and the .imd file. I found date and time but not the name of the ...
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1answer
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Random Forest land cover classification in ArcMap?

I am an undergraduate student working with a very large data set (to me), and who has NO experience with R, but is fairly comfortable with ArcMap. I have about 60GB of 8band 1m satellite imagery of ...
6
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1answer
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SAR - Using the Intensity or the Amplitude for the classification

In a Sentinel-1 Level 1 Ground Range Detected SAR data product, Intensity = Amplitude * Amplitude. Should the intensity image or the amplitude image be used for radiometric calibration when using ...
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3answers
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How to generalize training data for a random forest classifier?

I am working with a random forest classifier in eCognition (new with eCognition 9.0). The image shows 8 NAIP tiles I am attempting to classify using approximately 100 training points. The training ...
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1answer
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Selecting bands of image collection in Google Earth Engine?

I want to use the Landsat 8 surface reflection collection (LANDSAT/LC08/C01/T1_SR), which contains the 7 spectral bands plus some extra mask bands. I want to run my algorithm on just the 7 spectral ...
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1answer
822 views

Pan sharpening of SPOT and Landsat images

Is there a way I can pansharpen SPOT and Landsat images? I have Panchromatic bands from QuickBird and WordlView-2 images and would want to pansharpen Landsat and SPOT, while still retaining features ...
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3answers
995 views

Colour matching satellite imagery from different time periods

Is it possible to colour match two separate satellite images taken at two different times? I am working with two high resolution, multispectral images that were taken approximately one year apart and ...
6
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3answers
211 views

Classifying small structure in water using IR band

I was wondering how to identify small structures (eg. beacons) in a water body? I have worked with RGB images and its almost impossible to classify waterbodies in these images. How does the IR band ...
6
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1answer
183 views

InSAR processing: why can't we just compute distances directly from time delays?

My question can be very basic, but even after studying quite a few tutorials on InSAR processing, I still do not understand one thing: if we know a wavelength, speed of light, a time delay it takes ...
6
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2answers
221 views

Sentinel-2 images color cast

I work with Sentinel-2 images (Level-1C products (top-of-atmosphere reflectances)). I would like to know why some of the images do have this blue(?) undertone/color cast. I think those images are from ...
6
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1answer
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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 ...
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1answer
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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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1answer
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How can I parse modis MOD13Q1 quality layers in R?

I'd like to parse MOD13Q1 VI quality layers in R. My original code must have been incorrect, because it gave lots of "deep ocean" flags in the middle of Brazil. After the changes suggested by Mikkel,...
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2answers
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Transform SPOT5 images to natural color images

We're currently using PixelSense to convert raw SPOT5 images to natural color ones for display and printing. Do you know a good algorithm to perform the same task as we want to ingest raw images in an ...
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3answers
249 views

Landsat 8 striping/banding citation

Does anyone have or know a citation for the Landsat 8 striping that affects some scenes (Brazil shown here). It's apparent in all bands (B3 here at 100% stretch) and is present in both RAW and ...
6
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1answer
164 views

Landsat ML classification: Apply accuracy measures to scenes without reference data?

I applied supervised maximum likelihood classification to a yearly stack of Landsat images (resolution 30m). The land cover classes are related to coniferous forest, i.e., forest, clear-cut, fire, ...
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75 views

Residential tree cover for surveying?

Can someone point me in the direction of some high spatial resolution and reasonably recent satellite imagery for central Canada (Manitoba)? I am trying to determine whether I can generate accurate ...
6
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1answer
2k views

Methods of cloud shadow detection for Landsat data?

Detecting clouds doesn't seem to be much of a problem, rather the challenge is in selecting cloud-shadow classes that don't also include coastal areas, agriculture, etc. For a project I'm working on, ...
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6answers
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DEM generation from ASTER L1B imagery using FOSS

Is there any (photogrammetric or other) FOSS package to support the generation of a DEM from ASTER L1B products (i.e. combining the spectral bands 3N and 3B)? Are there any practical examples or/and ...
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0answers
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QGIS 2.4.0-Chugiak: How to threshold NDVI to calculate emissivity for land surface temperature [closed]

I am analysing urban heat island using thermal band 6 of landsat TM-5 sensor with respect to Normalized difference vegetation index that derived from the Band 3(Red) and Band 4(NIR). Lansat TM years ...
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0answers
712 views

Land Classification with Spectral Python (SPy) [closed]

Does anyone have experience working with the Spectral Python module for land classification? The following k-means clustering example takes an iterative approach to classification through pixel ...
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3answers
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Pixel-based and object-based classification!

I would like to understand if pixel-based classification algorithm (e.g. Maximum Likelihood classification ) can be used for object-based classification (i.e. after a segmentation procedure). On the ...
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3answers
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Moisture Interpretation from Landsat Images

I am working on a "land suitability for crop" project. Can anyone let me know how to get any type of information which can be related to moisture index of soil? I have Landsat 5 data with band 3 and ...
5
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3answers
366 views

Download MODIS data for Mexico

I would like to download MODIS npp images for Mexico but I cannot figure out which files correspond to the country. How can I associate each tile to its location without looking at the million of ...
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2answers
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Best Landsat-5 TM band combination for detecting fire scars [closed]

I am looking for the best band combination with Landsat 5 imagery to detect fire scars.
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1answer
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Open Source Alternatives to ERDAS IMAGINE ATCOR?

I have been using ERDAS IMAGINE's ATCOR extension for ATmospheric CORrection of ASTER imagery. What opensource options exist for atmospheric correction of ASTER Level 1B products? I'm primarily ...
5
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2answers
874 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 ...
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2answers
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Is it possible to get Elevation from a Satellite Image?

I would like to get elevation from a satellite image. I would be needing resolution less than or equal to 5 m. Is this possible? If yes, how can I procure these images and where?
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3answers
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How to process Sentinel-2 data from AWS

Sentinel-2 imagery granules downloaded from AWS archives (http://sentinel-pds.s3-website.eu-central-1.amazonaws.com) have a little different data structure than the original granule sub-folders of ESA ...
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4answers
867 views

What satellite imagery would help to show spring locations?

I've got lots of tiny streams on a hydrography shapefile. Historic texts indicate that certain ones have headwaters at "sources" or springs, and I want to try to find these. Browsing the historical ...
5
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2answers
994 views

What is NIR LiDAR?

Can LiDAR sensors collect near-infrared (NIR) data at the same time or does there need to be a separate NIR camera that is combined with the LiDAR data after collection? Blue Marble makes reference ...
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2answers
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How do I deal with tiles in the Orfeo Toolbox segmentation?

I'm using the Orfeo Toolbox for segementation of large Very High Resolution Satellite images. It performs very well and i'm mostly very happy with it. But I still get some weird/bad results that I ...