All Questions
1,417 questions
1
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46
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Sentinel-1 and Sentinel-2 images show differences in flooded area extent for the same location and date
I am working on flood mapping using Google Earth Engine (GEE) and have observed a difference when comparing Sentinel-1 and Sentinel-2 images for the same location and date.
Sentinel-1 (SAR): Shows ...
0
votes
0
answers
21
views
Gdalwarp() based orthorectification using computed RPCs has distortions and artifacts
Orthorectifying an image with RPCs computed (using this library) based on a manually marked set of GCPs and an elevation model gives an output which looks something like what I've attached below ( ...
- 1
0
votes
0
answers
21
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Vegetation Change Tracker and GEE: What do the six bands output by the VCT algorithm mean?
What do the six bands output by the VCT algorithm mean, especially the values of the VCT landcover mask. I don't know what they mean.
Vegetation Change Tracker, an automated approach for ...
0
votes
0
answers
29
views
How to resolve ENVI Flaash ACC error
I am currently preprocessing aster radiance at sensor(level 1b) images which I downloaded as .tif files, and can be accessed via this link from Earthdata. These are radiometric and geometrically ...
1
vote
0
answers
36
views
Opening .img file created in Erdas Imagine 2023 in Erdas Imagine 2022
I am having an issue working with a file created in Erdas Imagine 2023 in Erdas Imagine 2022. I ran a tool with the output .img. However, the .img format seems to be different in Erdas 2023 vs Erdas ...
- 11
0
votes
0
answers
14
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Landsat 8 C2 L2 FOR NDVI
When I download Landsat 8 C2 L2 image from USGS and apply directly NDVI formula the value is ok it is in range -1,+1 while where I am applying scale factor which is (0.0000275)-(0.2) for each band ...
0
votes
1
answer
17
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Is it possible to find (or derive) a Land Surface Temperature product with a resolution of 50 metres or less?
I need to do a temperature assessment at a suburb level, hence the requirement for high resolution. The best I could find is 100m derived from Landsat, which apparently reaches a 30m res in the US. Is ...
1
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0
answers
51
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What is the difference between surface reflectance and top of atmosphere (TOA) reflectance?
I was told that during winter it is better to use TOA because SR is not good for winter. But I didn't find any files describing it. Can anyone explain the difference of these two and why they perform ...
- 19
0
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0
answers
11
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Calculate the error distribution of fractional abundance values between classes (a spectral mixture analysis issue)
I am trying to estimate the distribution of the under- and overestimation errors that I found in the outputs of a spectral mixture analysis (SMA), i.e. abundance fractional maps (AFM).
Specifically, ...
- 89
0
votes
1
answer
348
views
Sentinel-2 QA60 band missing?
When performing cloud masking for Sentinel-2 images using QA60 band, I found that after February 2024, the QA bands of Sentinel-2 images are all "masked".
In this case, I can't perform cloud ...
0
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0
answers
120
views
scp landsat not showing
why not showing landsat in preprocessing obtion?c
I cannot find Landsat in my preprocessing toolbar.
I have only preprocessing options of clip raster bands, image conversion, masking bands, mosaic ...
- 1
1
vote
1
answer
128
views
How to create the fishnet grid in GEE using JS code editor?
I want to create a 10*10 pixel size grid for my AOI.
1 pixel = 10m
var cellSize = 100; // Size of each grid cell
// Get the bounds of the AOI
var bounds = aoi.geometry().bounds().coordinates().get(0)...
0
votes
0
answers
160
views
Convert an .xml fil to .tif in ArcGIS Pro
Using ArcGIS Pro 3.3.
I downloaded Sentinel 2a data from Copernicus, a few months ago.
trying them out today and finding that I have XML and JPEG files, no TIFF.
this is what my Copernicus data looks ...
0
votes
1
answer
54
views
Empty Metadata table in Semi-Automatic Classification Plugin of QGIS
I am working on Landsat 8 images using QGIS 3.36.2
When I want to convert clipped images to reflectance in Semi-Automatic Classification Plugin, nothing is displayed under the metadata table even ...
- 111
0
votes
1
answer
60
views
Source for satellite images without geometric correction
I need satellite images for a university project and they must not have passed through geometric correction. So far the images I have found are already geometrically corrected in some form. Is there a ...
3
votes
1
answer
2k
views
Converting image data type from uint16 to uint8 using Python
I have a uint16 image, but when I want to convert this image to uint8 data type, I get bad results. I'm sharing my entry image and the result below. My image is a 3-channel RGB image.
original image: ...
- 75
4
votes
1
answer
506
views
What does "post to post" mean?
For example, when someone talks about the "post to post" elevation error of a DTM, what exactly are they referring to?
- 69
1
vote
0
answers
277
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Strange stripes on Google Maps in the region of the October Revolution Island
On 2024-04-16 one can see strange stripes located roughly at 79.86317, 94.64563 in the region of the October Revolution Island.
What could be the source of these stripes in an end product?
I mean, ...
- 10.9k
0
votes
0
answers
25
views
Why if I spoof the position with GNSS Analysis MATLAB Google code,I get a spike of horizontal speed but it continue to be active while should be const
I'm using this GNSS Analysis Matlab Google code
to analyze the measurements performed via GNSSLogger app.
I was initially in Palermo,Sicily and tried to spoof to Rome. I get this
Horizontal speed ...
- 11
0
votes
1
answer
115
views
QGIS plotting from a multiband raster in a ternary diagram
I am working on creating a (remote) superficial geological map using ASTER imagery in QGIS.
I have made several RGB composites including Abram's ratio and Thermal Infra red indices to aid in ...
- 76
0
votes
1
answer
42
views
Random Forest error
I have tried a LULC classification using random forest algorithm in Google Earth Engine but error showing:
Layer error: Property 'B2' of feature '0' is missing.
My script code: https://code....
0
votes
0
answers
18
views
Coregistration for training and validation
If I want to use a 30-m raster as an independent validation dataset for a remote sensing analysis of 10-m and 20-m satellite imagery bands, do I need to coregister the 30-m raster with the 10-m and 20-...
1
vote
1
answer
57
views
Direct use of Sentinel 2 L2A imagery for vegetation analysis
I am working on my research to calculate the green vegetation in the study area using sentinel 2 L2A 10m resolution. Do I need to perform any correction or smoothing before analysis?
- 13
0
votes
0
answers
20
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Why are my calculated normalized difference indices maxima bigger +1?
I’m wondering about the results of my indices, e.g. the NBR maximum is +1.37 (see picture below),and as we all know the NBR (like any other normalized difference index) should be between -1 and 1…
...
- 1
0
votes
0
answers
46
views
What data does clustering use from multiple raster files?
I currently have a series of rasters of the same area across different times. The data is categorical: the product of a supervised classification used on LANDSAT data run on ERDAS Imagine. Each ...
- 23
1
vote
1
answer
97
views
Change select color in a raster in QGIS using Serval or Value tool
Is it possible to edit the table view of a raster that you see in the Value tool?
Alternatively
Using Serval, once we have a selection polygon can we choose a specific range of raster values within ...
- 8,298
2
votes
1
answer
109
views
Does QGIS have a functionality similar to Flicker in Erdas Imagine?
I am trying to replace an Erdas Imagine workflow with QGIS and I have got most of it working but can't find a solution for fliker. We have it set to turn an image on and off every few seconds to ...
- 8,298
0
votes
0
answers
34
views
Erdas - Export LUT Instead Of Real Values
I am using Erdas 2022.
I have NDVI index of an imaging, and after creating it, the view shows a LUT which is not the original pixels, which is essentially the automatic stretching of the program.
I ...
- 101
2
votes
1
answer
1k
views
Understanding Landsat 8-9 Pixel Quality Assessment (QA_PIXEL) Value Interpretations
Table 6.3 here describes the Landsat 8-9 Pixel Quality Assessment (QA_PIXEL) Value Interpretations.
Value 54596 contains both "clear" and "cirrus". What am I to make of it? A pixel ...
- 1,879
1
vote
0
answers
61
views
Is there a publicly available higher resolution equivalent to Landsat 8/9 TIRS?
I have a strong feeling the answer to this question is no. That said, I'd love to be wrong.
I'm looking to estimate land surface temperature at a higher resolution than the 100m bands (10 and 11) on ...
- 214
0
votes
0
answers
46
views
Excluding 'No Data' Pixels When Counting number of pixels in an AOI with ERDAS IMAGINE
I'm working with Landsat imagery in ERDAS IMAGINE 2014 and have encountered an issue with 'no data' pixels within my Area of Interest (AOI). The AOI includes unwanted 'no data' pixels that are ...
1
vote
0
answers
108
views
DIY Multispectral camera Rededge
I am trying to build my own multispectral camera using a Raspberry Pi, RGB camera, and Near IR Camera. My original goal was to measure the NDVI index. However I am now interested in the NDCI index as ...
- 11
0
votes
1
answer
94
views
Landsat 8 - eleven bands and corresponding files
Landsat 8 zipped file downloaded via EarthExplorer consists of several files.
Which of the files correspond to the band 8, 9, 11?
LC09_L2SP_x_y_z_02_T1_ANG.txt
LC09_L2SP_x_y_z_02_T1_MTL.json
...
- 91
0
votes
0
answers
72
views
What does the metadata tell you about an image and its sensor?
I'm using a software called ERDAS and my tutor says that the Metadata can be used to detect which sensor your image came from. Is there anything you can tell me that links the metadata to the sensor?
...
0
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0
answers
22
views
Merging Subswaths with ERDAS Imagine
Does anyone have experience with merging subswaths of a SLC Sentinel 1 image in ERDAS Imagine? I cannot find the right function for it.
2
votes
2
answers
49
views
On the edge of the swath and the reflection of the sun
In the Sentinel-2 image data, there is an overexposure near the water surface. I have examined several images and found that it is common to the eastern edge of the swath, so I think it is a ...
- 23
0
votes
1
answer
49
views
Use of convertmodis_gdal.convertModisGDAL
I tried to get ET and PET layer for MOD16A2 by using convertmodis_gdal.convertModisGDAL:
modisconv = convertmodis_gdal.convertModisGDAL(hdf, output, "(1 0 0)", 500, outformat='GTiff', epsg=...
- 3
0
votes
1
answer
55
views
Python reshaping issues of 13 band TIFF to run through Random Forest classifier
I'm having some issues that I'm seeking help with. I have a 13 band TIFF and a trained random forest classifier with 13 features that are in the correct order to match the 13 bands. I haven't made it ...
- 11
-3
votes
1
answer
929
views
Segment Anything Model integrated with QGIS
The Meta Segment Anything Model seems very powerful at image segmentation, and there are many development on remote sensing image segementation applications, Is there any QGIS plugins integrated ...
- 31
0
votes
1
answer
128
views
How to Fix: Layer error: Computed value is too large in Google Earth Engine
I conducted a landcover classification, distinguishing between mangrove and non-mangrove areas. For each landcover type, I gathered fewer than 10 samples. I utilized Random Forest (RF) for ...
- 99
3
votes
2
answers
492
views
Problems importing DJI Phantom images into QGIS
I am trying to import DJI Phantom 4 multispectral imagery into QGIS. I have imported the imagery but the images are not in the right location (showing near the coast of Africa when they should be in ...
- 41
1
vote
0
answers
176
views
GEE Global Forest Change Hansen treecover and lossyear layers contradiction
In the Global Forest Change Hansen dataset, why does the layer lossyear shows several pixels as deforested in the year 2001 when the layer treecover2000 indicates that those same pixels had no forest ...
- 11
1
vote
0
answers
217
views
Downloading photos from Google Street View and use then for QGIS Atlas
I am carrying out a remote sensing work (land use mapping of the Dakar metropolitan area based on sentinel2 images classifications).
In order to compensate for the absence of a ground campaign and ...
- 919
0
votes
1
answer
66
views
Does Landsat satellite image should have raster value to -1 and 1?
I am calculating the NDVI for Landsat-8 using the formula as shown below:-
But the pixel value rendered is as shown below: -
But the NDVI values need to be between -1 and +1 however, the value ...
- 83
0
votes
1
answer
74
views
Converting VICAR data to TIFF
I want to convert the VICAR data found at this ASU link
to TIFF that I can use in ArcGIS Pro.
How am I able to do this?
- 69
0
votes
1
answer
176
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Creating square polygons from two known diagonal corner vertices
Similar question to
How to make a square out of two points?-- I have a CSV file with coordinates for the bottom left and top right corners of multiple sampling plots and would like to make individual ...
- 11
0
votes
0
answers
570
views
Downloading Sentinel-2 images: "offline products" in Copernicus Open Access Hub site
I want to download Sentinel-2 Level1C images for the specific dates. So I tried to download them from Copernicus Open Access Hub site. But I can't download since it says the product is offline,
...
- 115
1
vote
1
answer
52
views
Monthly sentinel-2 Max and Mean NDVI, and B9 values extracted to CSV
When trying to run this code I get an error:
Expected Type: Image(unknown bands) actual type:ImageCollections
I would also like to maintain the ID column to be the ID column in my shapefile(labelled ...
- 13
0
votes
0
answers
102
views
Converting Hansen Global Forest Change 'Forest Loss Year' into panel data structure
I downloaded the hansen deforestation loss year layer from the website (https://earthenginepartners.appspot.com/science-2013-global-forest/download_v1.7.html).
It is a single raster with one band. ...
- 21
1
vote
2
answers
590
views
I want to test the statistical significance of the NDVI change in R
I have 20 Sentinel 2 satellite data for the period from 2017 to 2020, with 5 satellite scenes each for the months from May to September, covering one vegetation season. I am interested in whether the ...
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