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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Cropland field delineation using OpenCV and Google Earth Engine
I want to follow the methodology in the following article in order to find field boundary delineation automatically: "Multi-Temporal Crop Type and Field Boundary Classification with Google Earth ...
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Error with ROI Semi Automatic Classification Plugin QGIS 3.4
I have troubles for making ROI with SCP plugin in QGIS 3.4.
I dowloaded some landsat images with the plugin and trying to create ROI. To do it, I made a Bandset with DOS1 atmospheric correction, ...
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Predicting the whole image through trained classifier and visualize it as classified landuse and landcover image(LULC)
I am working on LULC classification of Sentinel-2 image(4-bands) using Machine Learning algorithms. I split the whole image into 64*64 patches and assigned class label (builtup, barren land, water and ...
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Sentinel 2 preprocessing with R
I need to transform Sentinel 2 L1C imagery to preprocessed Level 2A data.
Ideally this should happen in R, as the remaining processing stack is already done in R.
Are there ready preprocessing ...
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Classify image using segmentation analysis using QGIS and OrfeoToolbox
I am working on a project where we have made a RGB orthomosaic using a drone which I want to classify using QGIS. I am not a fan of unsupervised classification, and I started exploring the ...
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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 ...
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Error occurring when converting to dB during the python-based classification
I am trying to perform an object-based classification using a python-based script with rsgislib. Although, when converting to dB, an error is appearing. Any ideas why is this happening?
Create and ...
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Is it possible to detect human settlements by night light data?
I am working on a project in which human settlements are identified using geo-tagged Twitter data. Since this project is focused on developing countries (mostly African), I am afraid that many human ...
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authentication error for accessing data product on scihub through wget
I am new to Sentinel(overall remote sensing domain) and currently trying to download the data products from Scihub using the wget utility on Windows10 machine. However I am getting the below error. I ...
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Aligning raster layers in python script
I am wanting to automate the preparation of raster layers from Sentinel-2 to be used in an unsupervised classification. So far, I have been able to write the following script, which will successfully ...
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Negative reflectance values after topographic corrections (cosine correction and modified Minnaert correction)
I am trying to manually correct the surface reflectance values of some Landsat 7 and 8 images. I'm using Minnaert modified method, which uses the cosine correction as one of its inputs (see below the ...
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MODIS Imagery Orthorectification (Open Source)
I am looking for an open source free software/tool for orthorectification/Geometric terrain correction of MODIS imagery.
I have looked at ESA (European Space Agency) SNAP but this sensor type is not ...
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Import GPS SINEX (for velocity analysis) into Sarscape or processing with others software
I try to import GPS snx. into Sarscape 5.2 (use GPS Import tool) and getting error
115) ) gps_type : [sinex]
116) ) generate_kml : [OK]
117) ) generate_shape : [OK]
118) ) ...
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Guide to aerial or space data types and availability
I am overwhelmed by the variety of types of satellite and aerial data (images?) available online. For example, at the USGS Earth Explorer data page, I see AVHRR; CEOS;Ikonos and OrbView; EO-1; GLS; ...
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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 ...
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Landsat TM, ETM+: what are radiometric calibration coefficient of each sensor to convert DN to radiance
The Landsat TM Image data that comes with zipped folder contains metadata text file in which all necessary information have been written. In order to further process that data, first DN to radiance ...
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ASTER mineral indices with VINR and SWIR data
I need to run a supervised classification on ASTER data in order to map a rock formation, which is composed of chert. There is no shortage of indices which can be used to highlight silica rich ...
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R: Can raster predict function pass to predict.rfsrc (a prediction function in a parallel verion of RandomForest)?
It seems that raster predict function can pass to predict.randomForest by setting the "type='response'". I am using a parallel version of randomForest package called the "randomForestSRC" and I am ...
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Interpreting NDVI value on water?
There is a surreal thing on my NDVI images. NDVI values on lake is ranging from -0.04 to 0.7. (The lake surrounded by forest and has freshwater). Theoretically, negative value of NDVI is correspond to ...
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Principal Component Analysis in QGIS
How do I go about to perform a band ratio and Principal Component analysis in QGIS? I need to derive principal components from ratios of landsat TM bands .
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Localized Linear Histogram Match using python
I would like to use the local linear histogram match for filling the missing pixels of a Landsat 7 image with another older image (SLC Gap-Filled Products).
Do you have any idea how can I do it by ...
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Properly configure image segmentation on QGIS (Segmentation / MeanShift)
I'm trying to perform remote sensing on georeferenced historical satellite images (taken from Google Earth), using the segmentation algorithm from OTB.
In the parameters of the Segmentation algorithm, ...
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Using images from different Landsat missions and Sentinel-2 for machine learning
I am doing some image segmentation using random forests on satellite imagery. The events I am trying to detect are somewhat rare so my training sets are very limited if I want to use Sentinel-2 ...
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Alternative for Normalized Difference Built-up Index (NDBI) using satellite imagery with RGB & NIR bands
I am currently working with Planet SkySat multispectral imagery in Google Earth Engine (dataset description). It has only Red, Green, Blue and NIR bands. My objective is slum mapping and for this, ...
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GEE: projection error when exporting data to a table
I am trying to export some vegetation condition index data calculated from MODIS data on Google Earth Engine to a table, but keep getting the error:
Error in map(ID=3): Image.reduceRegions: Unable to ...
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Extract lines of rice terraces from satellite image
I have a Pleiades image and multiple rice field boundaries in a shape file.
What I want to do is for every feature in the shape file, clip the Pleiades image and detect the lines of the field terraces....
2
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Exporting EVI image on Google Earth Engine with visual parameters between -1 and 1?
I am having an issue with exporting an EVI image with the visual parameters between -1 and 1. On Google Earth Engine (GEE), using the inspector tool, the values are between -1 and 1, but when I export ...
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Calculating proportion of pixel containing vegetation (from sentinel 2 image stack)
My task is to perform a supervised classification of landcover across a huge (20,000+ hectare) property. I need to classify into three classes: forest, regenerating trees, and soil. We use s
Sentinel-...
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Calculating indices by Multiple polygons
Is there a way in QGIS to perform band math within each area defined by different polygons without clipping the rasters and performing calculations on each one?
I have a vector layer with several ...
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NDVI calculation problem
I have photo created by UAV, and I want to calculate bNDVI:
(NIR-blue)/(NIR+blue)
I have these bands (filter is ok -100%). So using QGIS I have values -0,1-> 0,3 - but bNDVI must be from 0,65->0,...
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ENVI band math incorrect values
I'm attempting to calculate vegetation indices in ENVI 5.2 using level-2 AVIRIS data in band math.
The indices I'm working with are Vogelmann Red Edge 2, normalized difference red edge, and red edge ...
2
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Supervised classification using endmember spectra (using ENVI 5.1)
We are trying to map land cover classes over a small watershed. We have selected training sites (during a field campaign in early 2017) and determined their spectral profiles on a Landsat 8 image ...
2
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Register an image using mutual information
I want a procedure for registering two images based on their mutual information. I took a pair of georeferenced radar images of the same location, edited the metadata of one so its position was off by ...
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Is there an arXiv-like electronic archive used by the remote sensing community?
Mathematicians, physicists, and (theoretical) computer scientists use arXiv extensively to share their preprints. Indeed, one could say that it's the established way to share one's research.
Is there ...
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ENVI shows colors of different RGB code the same in a bitmap image wrongly?
As you see in this picture which I've captured in MATLAB, there are two colors.
Red with the RGB code (255,0,0)
Brown with the RGB code (138,139,1)
I've tried to show the same picture in ENVI, ...
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Image classification: separating pine forest, lowland and upland hardwood
I want to classify 20 feet-resolution 4-band leaf-off image into lowland hardwood, upland hardwood, pine trees, and other (bare ground, water, roads etc). I am thinking to use randomForest package in ...
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eCognition - prevent rounding of raster values?
I have a WorldView2 image, which I would like to segment and classify in eCognition. The image has been pre-processed to Top of the Atmosphere Reflectance, therefore hasvalues between 0-1.
The ...
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i.atcorr - Landsat 8
I am trying to apply atmospheric correction to Landsat 8 scenes using i.atcorr. After tons of tests I am still struggling with the correct input and output range.
The results deriving from radiance as ...
2
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Finding pre-processed MODIS products?
I am trying to recognize burnt areas based on some MODIS products and I just realized that I am missing a bunch pixels from the coastline masking. As you can understand that is an issue because I am ...
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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 ...
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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 getting the wrong results from my FLAASH correction and believe ...
2
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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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Needed help to launch SVM classification in eCognition
I would like if somebody help me to launch SVM classification in eCognition.
Have you met any tutorials?
I was searching through ecognition community, but there I find only basic KNN supervised ...
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How to detect undisturbed forest plot in Mudumalai National Park?
I am looking for undisturbed forest plot (without logging for at least 50 years) in Mudumalai National Park (India) or around it. How to detect it using GIS or remote sensing?
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How to determine Visibility Map for Atmospheric Correction
As per Grass wiki: https://grasswiki.osgeo.org/wiki/Atmospheric_correction
the atmospheric correction could be done using a visibility raster in conjunction with an elevation raster. With regards to ...
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TIMESAT seasonality data (MODIS EVI)
I am trying to get seasonality parameters from MODIS EVI (MOD13Q1) for Indonesia. I have loaded data from 2013-2015, but the plotted time-series is shifted from what I expect. Indonesia has rice-...
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16-day-MODIS NDVI values seem to be wrong compared to my soil moisture ground data!
I'm using MOD13Q1 product of MODIS for estimation soil moisture. As I know, this product is made up of the maximum value of NDVI of each pixel over 16-day calculated NDVI values. The problem is that ...
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Calculating Aerosol optical thickness from Landsat 7
EDIT I have added question down
I am reading one paper and I found method to retrive AOT from landsat 7 image
This should be simplifield equation, because they assumed observation zenit as 0. Than ...
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GIS or Remote Sensing technique to map sub-surface features?
I am trying to delineate agriculture tile drainage in Midwest.
Does anyone know of any GIS and/or sub-surface remote sensing techniques to detect tiles/objects buried in shallow depth of soil?
Does ...
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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, ...