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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Can we do soil analysis for Nitrogen using remote sensing without field data for validation? [closed]

Background: Remote sensing is used for monitoring land cover change and for monitoring vegetation etc. In addition to that, it is used for soil analysis (alterations in soil properties) as well. There ...
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Classify Land Use Land Cover

I am asked to classify an image (Landsat 7 scene) for 2 different time period one for the month of July (Image 1) and the other December (Image 2) as shown below. Image for the month of July Image ...
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Change ruleset for images using E-cognition Software

I need to work on Object Based Image Classification using E-cognition software. The first map is as shown below: - This map belongs to that from the month of June. The other map is as shown below: - ...
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Detection of permanent changes in low resolution images

I want to detect permanent changes in lows resolution sentinel-2 satellite images, such as new buildings. Most research I found focuses on pair-wise change detection, which leads to many false alarms ...
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Sentinel-1 No products found - Looking for alternatives

I'm interested in doing flood mapping for a specific region, using SAR images from before and after the event. However, Sentinel-1 images are missing for this region (no products for more than 8+ ...
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How to calculate and export a table of mean of the maximum daily NDVIs over a particular period

I am using code from Nina Kattler to calculate the mean of max daily NDVI in particular districts in Mali over the growing season in 2019. The original code gives the mean NDVI over the growing season,...
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LandSat Land Surface Temperature - Python

I'm trying to determine if my code for determining land surface temperature is correct. The imagery contains a fire in the middle of October with snow mixed in so temperatures show be nice and ...
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Seasonal/monthly image composite generation for crop classification

I want to create multi-temporal composites for crop classification. However, when I print, I get 36 bands, but I was supposed to get 27, right? Besides, if I want to add multiple indices to each of ...
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Eliminate mismatch between two GeoTIFF satellite images

I have two GeoTIFF satellite images of the same area made on different dates (both are in the same CRS). When I open the images in QGIS, I can see that objects (buildings, etc.) have slightly ...
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Should I re-scale all the dataset to one scale before running them into model?

I have been working on the Flood susceptibility modelling and also have identified, collected and generated data of around 26 controlling factors(indicators). Furthermore, i'm going to put them into ...
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Eliminate mismatch between building images and their shape file annotations

I have little experience with geospatial data processing. I have a satellite image of an area (a geotiff file) and building footprints (building annotations) for this area (a shape file). When I open ...
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Mapping Soil Sealing and Water Bodies

I am asked which bands of Landsat 9 (or 8) is best for mapping soil surface sealing and water bodies at higher resolution. The band available in Landsat 9 is as shown:- From above band name; which ...
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Difference in color saturation in two Landsat-8 images

I have an assignment, where I have to do a classification and change detection between to satellite images. Now I have two Landsat-8 images from two different years (2019 and 2020) at captured nearly ...
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Image.classify: Classifier has no training data

function clip(image){ var image_clip = image.clip(corn); return image_clip } //corn,代码编号为0 function setcorn(feature){ var new_feature = feature.set({landcover:"corn",index:0}); ...
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Quick Map Services (QMS) Google Satellite Imagery Source Date

I have digitized landform features using the QMS Google Satellite as a reference basemap, and therefore need to know the date the image was taken. Is the plugin a 'live' updating feed from Google ...
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Change system:index of FeatureCollection ID in GEE to use Asset ID

I have a FeatureCollection with points loaded from an asset (shapefile). Since the system:index is empty, gee assigns a weird index to each feature (e.g. 000000000001, 0000000000a).Which causes ...
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Point value Change after projection - USGS DEM Raster VS Imagery Layer from Esri

I'm working on a project that requires National level DEM data, and Esri are providing the imagery layer (https://www.arcgis.com/home/item.html?id=0383ba18906149e3bd2a0975a0afdb8e). For the most part,...
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1 answer
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Calculate yearly change of LST data from MODIS in QGIS

I have monthly raster scenes (June) from MODIS for the period 2000-2020. So for each year one scene. Now I need to determine the yearly change in temperature for the month of June per pixel in degrees ...
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Why does no one use MODIS data from 2000?

While MODIS Terra was launched in 1999 and has data covering the year 2000, no one seems to use this in their analysis but rather starts the data collection from MODIS by the year 2001. Why is that? ...
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Bare soil detection using drone images

I'm working with drone images which separated to red, green and blue bands. My task is to determine bare soil pixels. I've tried to swap bands in the composite, and calculate different differences ...
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Error in generating a chart: No images in the collection intersect the specified regions

I am getting an error saying: no images in the collection intersect the specified regions thus my time-series chart cannot be generated. What might be the reason for this? The link to my code https:/...
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Atmospheric correction on Landsat scene using Python

I need to develop a workflow to analyze Landsat and Sentinel 2 scenes using Python and Xarray library. Generally I do this task using QGIS and Semi Automatic Classification Plugin, I'm using the ...
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1 answer
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Is there any way that can help determine the flow direction of a river in a satellite image (Landsat)?

For example, there is a stream in the following image, but I find it difficult to determine the flow direction of the stream. Should it be from south to north, or the opposite?
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No training data found (random forest algorithm in GEE)

I was trying to map rice in the Indramayu Regency in Indonesia using the random forest algorithm. It has responded with no training data found. When I used the same code previously for a different ...
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Band used for deformation estimation using In-SAR

Which polarization of SAR data (C-band - Sentinel-1A) shall I use to get a better deformation map of a mountain terrain - VV or HH?
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Vegetation Identification Plugin for QGIS

I was wondering if anyone knows of a deep learning plug in for QGIS that can identify different species of vegetation using high resolution RGB or multi-spectral imagery. Unfortunately I have not been ...
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Does a remote sensing image pixel value represent mean or max reflectance in a given band's wavelength?

This is especially relevant to multispectral sensors with wide bandwidths. For example, Sentinel-2's band 2 (blue band) has a bandwidth of 66nm, spanning ~459nm-525nm. If a pixel has a value of 1500 ...
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Is there a way to filter out polygons/lines using geometry in QGIS?

I am currently working on a project to digitize utility data, however my input layer is not classified. I am currently using length of the features to filter out unnecessary lines/polygons. Is there a ...
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Calculate transition of different NDVI classes from pre and post NDVI in Google Earth Engine

My competency in GEE is quite low. I have calculated 2 NDVI layers (pre and post-disturbance NDVI). I have separated these NDVI layers into 4 classes according to NDVI values. Now I need to calculate ...
6 votes
2 answers
184 views

Applying HDR (high dynamic range) rendering in QGIS

I want to automatically (without manual adjustments) apply HDR (high dynamic range) rendering to Sentinel-2 satellite images so that the image can distinguish between very bright objects (e.g. clouds, ...
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Adding external data to NDVI Chart google earth engine To have Two line charts on the same plot

I am trying to add external data to ndvi chart on google earth engine in order to have both lines on the same chart. I have been able to plot them differently but not able to merge them. Here is my ...
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Remove system start when plotting after calculating NDVI for shrubs and grass in Google Earth Engine using Copernicus

I have tried to select only shrubs and grass on NDVI but on plotting chart it shows this error. Here is the code. var feat =ee.Geometry.Point([33.15865673674562, -5.173302054347385]); var s2a = ...
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EarthPy plot scatterplot on top of plot_rgb

I am using earthpy.plot_rgb() for some satellite image because it works very well. However, I have the coordinates of a line that I'd like to plot on top of it with scatterplot, but I can't make it ...
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Approaches to distinguish bare soil from artificial soil in an urban context with Pleiades imagery?

My colleagues and I are trying to improve an existing landcover map by improving the distinction between bare soils and artificial soils (e.g. concrete, asphalt). We need a good detection of bare ...
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Why do I get an error when applying getInfo() in Google Earth Engine?

I'm working in an undergraduate project and just started using Google Earth Engine. Firstly, I need to filter some Sentinel-2 MSI images that cover my area of interest (a watershed with 55 km²) from ...
2 votes
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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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1 answer
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Projection problem with VIIRS-SNPP Deep Blue Aerosol data in R

I am having some trouble with VIIRS/SNPP Deep Blue Aerosol (DBA) product in R. After post-processing the data, I am not being able to obtain the data in the region of interest (ROI), hence I checked ...
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Google Earth Engine - NDVI chart - projection error

Once I multiply NDVI and EVI values with 0.0001, I get an error that is shown below. So I can't get the chart. Error generating chart: Projection error: Unable to compute intersection of geometries ...
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How to download a mask layer as array from GEE?

I am trying to create a cloud mask for my image, which I successfully did with the following code: // Masking clouds -> binary array var maskInside = function(image, geometry) { var mask_outside =...
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Projection best practices for applying ML to large scale Earth Observation imagery [closed]

I come from a data science background, rather than GIS, but work in a domain where remote-sensed imagery is widely used; so I'm still learning some of the do's & don'ts when it comes to the 'right'...
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Reusing regression or machine learning model in subsequent years

I have collected high-resolution UAV imagery and leaf area index (LAI) plot data. I plan on creating a model which uses my ground-based LAI to establish a relationship or train my UAV imagery. I will ...
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Remote sensing for algae blooms

I was curious if anyone knows what index is good for measuring algae blooms from multispectal imagery. I have tried using NDVI with minimal success but I have heard that blue/green and blue/red also ...
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Difference between two Google Earth Engine functions

Do you know what is the difference between ee.Clusterer.wekaKMeans and ee.Clusterer.wekaCascadeKMeans?
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Dividing reflectance values of Sentinel-2 sets of bands using rasterio

I need to divide the reflectance values of a Sentinel-2 sets of bands. To do this, I have to divide each band by 10000 when I read in the band to write the stack. I have an example of my code snippet ...
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Is ground sampling distance (GSD) related to the sampling of the object we have on the ground or to the output that comes from the sensor?

I am studying the GSD for a remote sensing mission. I don't understand if the GSD is related to the sampling of the analog output generated by a sensor or to a given scene on the ground. My textbook ...
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Why do I get wrong NDVI, EVI values in crop monitoring?

I have been monitoring agriculture lands with Sentinel-2 S2MSI2A data. I'm calculating NDVI and EVI for the vegetation. The NDVI values are slowly increasing because the growing crops which is look ...
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How to distinguish never deforested from never forested using Hansen forest data

The Hansen Global Forest Change dataset has a lossyear band, for which 0 values mean no loss. However, no loss can either mean: The pixel was forest in the beginning of the sample (2000) and still is ...
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Displaying raster data information in specific coordinates

I am currently trying to figure out how to retrieve the information in a specific point in QGIS. I opened a netcdf file containing information about chlorophy-a concentration in the Mediterranean Sea. ...
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DEM coordinates do not align other data layers

I recently downloaded Original Product Resolution (OPR) Digital Elevation Model (DEM) data for some analysis. The DEM does not align with any of the other data sets I have for the area. I have ...
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Changing boundary color and increase thickness of a feature in Google Earth Engine

I'm trying to find elevation using GEE, but I want to set boundary thickness for each country for better representation. How can I do this? Here is the link for code. You can see when two countries ...

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