All Questions
69 questions
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14
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Ploting a landsurface time series using Landsat8 images on Google Earth Engine
The original code was for MODIS data, but I would like to do a time series with Landsat8 Tier 2 Level 2, which already has the LST values, you just have to apply the scalling factor. I modified the ...
0
votes
0
answers
35
views
How to the image date/ metadata used when using the .median filter in GEE?
I am processing LST, NDVI, NDBI, & UHI data in a 1 year period. I used the .median filter function for filtering the dates.
My question is, how do I know what images to use? I've tried the ...
1
vote
1
answer
163
views
Problem downloading images via landsatxplore.api
I use landsatxplore python package to download some landsat images. I have used it to download images taken one year before and it worked. I have written some Python code to download the images via a ...
- 792
1
vote
1
answer
116
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Google Earth Engine Landsat NDVI
I'm trying to map deforestation using Landsat NDVI time-series. But unfortunately I can't find the data from 2022 - 2023, on the other side data before that year is available. Can someone explain me ...
- 31
0
votes
1
answer
94
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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
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0
answers
222
views
Timelapse in GEE
This code is working and the video is active but only images are there. I couldn't add the date (year) to the images. How can this step be accomplished?
// Define your collection
var collection = (ee....
0
votes
1
answer
313
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Calculating LST from Landsat 8 in Google Earth Engine display a blank image
Why is it that when the following GEE code is used to calculate the lst of landsat8, the data statistics are correct, between 29°C and 55°C, but the output image is blank and the file is only 14.9MB?
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1
answer
153
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Landsat 8 geometry of image
I'm trying to find actual geometry of the Landsat 8 image.
I retrieve Landsat data from ONDA service using EODAG. Onda provides Landsat 8 images in TIF files in epsg:4326. And it looks so:
Also, in ...
- 1
4
votes
1
answer
415
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(GEE) Constant value in Chart after applying scaling factor to LANDSAT
After applying a scaling factor to my LANDSAT collection 2 level 2 data the values seem to be off.
var addNDVI = function(image) {
var ndvi = image.normalizedDifference(['SR_B4', 'SR_B5'])....
- 635
1
vote
2
answers
718
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Does USGS Landsat 8 Collection 2 Tier 1 TOA Reflectance need cloud mask before NDVI computation
For computing the NDVI I want to use USGS Landsat 8 Collection 2 Tier 1 TOA Reflectance LANDSAT/LC08/C02/T1_TOA does it need cloud masking or any other form of ''cleaning'' before I can use it?
- 635
0
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0
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213
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NDVI values of Landsat 7 and 8 differ for same location and year (GEE)
The NDVI values for the same location and same year differ between Landsat 7 and 8. Even though I would expect a small difference the difference I found is too high.
var collection1 = ee....
- 635
0
votes
1
answer
28
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What is the ground surface reflectance of Landsat8 Level2 data?
I would like to know the definition of Level2 ground surface reflectance.
For example, up to how many kilometers above the ground is it defined as surface reflectance?
It is possible that I am ...
1
vote
0
answers
1k
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Earth Engine: Landsat 8 QA_PIXEL issues with cloud, shadow, and land masking
Using the QA_PIXEL band in Landsat 8 to mask out clouds, cloud shadow, and land often masks out large areas of water. The QA_PIXEL band identifies these water areas as land and cloud shadow, when this ...
- 151
1
vote
0
answers
482
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Landsat 8 Collection 2 cloud-free mosaics in Earth Engine
I am trying to get cloud-free mosaics from 6-months periods of Landsat 8 Collection 2 Surface Reflectance.
So far I've used geetools. My code consists of multiple modules so I can't paste it all here, ...
- 746
4
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1
answer
6k
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How to make a cloud-free composite for Landsat 8 Collection 2 surface reflectance in Earth Engine
Suppose I want to create a cloud-free composite of Landsat 8 Collection 2 surface reflectance images for summer 2021 of Washington state, USA. How can I do it?
Here is the code to build the collection ...
- 6,233
0
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1
answer
267
views
Are Landsat satellites exactly sun-synchronous?
Sun-synchronous satellites are known to pass over any given point of the planet's surface at the same local mean solar time (link-to-wiki). Landsat is one of these sun-synchronous satellites.
I'm ...
- 71
0
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1
answer
1k
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Landsat 8 Collection 2 (C2) Level 2 Science Product (L2SP)
I am exploring data sources for land surface temperatures (LST) for summer 2021. From Landsat 8 Collection 2 Surface Temperature (https://www.usgs.gov/core-science-systems/nli/landsat/landsat-...
- 25
2
votes
1
answer
942
views
Difference between TOA and SR in Landsat sensors
I am looking at long-term mangrove forest change (1990-2020) in Indonesia using Landsat satellites. These are the years and sensors I have chosen:
2020- Landsat 8 T1 SR // 2010- Landsat 5 TM T1 TOA // ...
2
votes
1
answer
1k
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GEE Tile error: Expected a homogeneous image collection, but an image with an incompatible band was encountered when calculating VCI from Landsat
I'm trying to calculate the VCI (NDVI - minNDVI)/(maxNDVI-minNDVI) for a collection of landsat 5 merged with a collection of landsat 8 because I will need to do this for different periods covering ...
- 105
3
votes
0
answers
863
views
EVI in Google Earth Engine
I calculated the EVI for a Landsat image from -1 to 1. However, when I use the inspector tool in GEE and click around on my image, I see I have values less than -1. Is there something wrong with my ...
- 57
0
votes
1
answer
248
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I need to export the list of IDs of the satellite images available in Google Earth Engine to work in Excel. I just need the ID
I am working with Google Earth Engine and I need to export the collection as a list, to be able to work it in Excel. What I mean is being able to export the list of the ID of the available satellite ...
1
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0
answers
253
views
Is there a way to bulk download Landsat data through cmd prompt or Python?
I know I can download landsat data through earth explorer and they have their own Bulk Downloader here: https://lta.cr.usgs.gov/EEHelp/BulkDownloadApplication
But I am wondering if there is ...
- 543
3
votes
1
answer
549
views
Mask clouds across multiple images using Google Earth Engine
I Have multiple Landsat8 images at the same place in different years.
I want to have a cloud mask for each image, then merge the mask so that all images will be masked with a same aggregated mask.
I'...
- 376
1
vote
2
answers
39
views
Query about Satellite Thermal Imaging [closed]
I am working on my undergraduate thesis and for this I need access to Satellite Thermal Imagery. I have spent some time looking at how to get these Images. I know from my investigation in the last 1 ...
- 19
3
votes
2
answers
2k
views
Time series for MultiPoint geometries in Google Earth Engine
I am trying to generate time series for a set of points in earth engine. I am attempting this for multiple datasets, but for now let's do NDVI with Landsat 8. My problem lies (i think) in step 6. ...
- 274
2
votes
0
answers
95
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Surface Temperature + Air Temperature in Landsat image comparisons
Quick question about relating Landsat Surface Temperature to locally recorded Air Temperature on a given day:
Are differences in local air temperature captured by the Landsat ARD ST imaging process?
...
- 21
2
votes
2
answers
2k
views
Landsat 8 - Reflectance Values
I downloaded some Landsat 8 OLI/TIRS C1 Level-1 images from EarthExplorer. I was hoping to get reflectance data out of the blue, green and red band; however, when I opened those images in ArcMap, the ...
- 339
5
votes
2
answers
23k
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Calculating LST from Landsat 8 in Google Earth Engine?
I'm trying to write a code for Land Surface Temperature (LST) from Landsat 8 images in google earth engine. I'm using the code of this question as a guide and I succeeded at intermediate steps but I ...
- 79
0
votes
1
answer
1k
views
What's the time zone of the timestamp of LANDSAT Images?
I am using google earth engine just to print the timestamp here of LANDSAT Image. I am using the geometry of a part of Chennai which is in India.
// Filtering Data with Date and Geometry
var Data2 = ...
- 349
2
votes
2
answers
2k
views
Why Landsat images are tilted/rotated?
When I browse images from https://earthexplorer.usgs.gov/, I can see that all of the images from Landsat are all tilted/rotated at a certain angle.
Why are they rotated? And what's that for?
Below ...
- 133
3
votes
2
answers
407
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Computing NDVI in ArcMap from Landsat 8 "Analysis-Ready" Surface and TOA Reflectance Products
The internet is full of various contradictory advice on corrections one can make to get NDVI computed from Landsat 8 to fall between -1 and 1.
This is for instructional purposes, so I hope to use ...
- 1,383
2
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0
answers
223
views
Why don't Landsat 8 image extents match WRS2 polygons?
The question doesn't need too many explanations, but the following picture illustrate the problem very well.
I sort of understand why they don't match on width. The satellite drifts away of its path ...
- 774
2
votes
1
answer
2k
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Apply a cloud filter to a Landsat8 collection in Google Earth Engine
I have loaded a collection of landsat8 images bounded by sudanmaps. My goal is to filter out all images that have cloud in it. I tried the method given in Filter Landsat images base on cloud cover ...
- 63
0
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0
answers
1k
views
GEE Landsat SR year composite // mask cloud / shadow out w/ other method than quality pixel
Has anyone found a good solution to mask out cloud/shadow cover not using quality assessesment pixels or combining it with something else?
I am trying to generate cloud/shadow free composite for a ...
- 1
0
votes
0
answers
186
views
Calculating the mean between several raster layers, with NoData values
I have several Landsat 8 scenes from which i have derived the surface temperature. To obtain an average, I would like to generate the mean between all my scenes. However, prior to this I am planing to ...
1
vote
1
answer
478
views
What bands should be used to identify clouds using the cloud function of the landsat package in LANDSAT 8 scenes?
I am trying to use the clouds function of the landsat r package to identify clouds in my LANDSAT 8 scene.
In the package help, it is said that reflectance bands 1 and 6 should be used:
clouds(...
- 577
1
vote
0
answers
411
views
RS&GIS plugin produces no outputs
I'm trying to look at some landsat images and thought I would give the RS&GIS a go, as a way of creating true and false colour composites. I'd like to visually inspect the vegetation my project ...
- 29
0
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0
answers
1k
views
Landsat 8 bands of 432 looks too dark in ArcGIS
I have created a composite map using the combination of Landsat 8 bands of 4, 3 and 2 (I read this combination gives true natural color) to see the scene in true color in ArcGIS, but it looks too dark....
- 315
2
votes
0
answers
434
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Computing stats with data ignore values - ENVI classic
I'm using ENVI classic (5.4.1) and trying to compute basic statistics from a Landsat-8 scene. When I mask out certain pixels (water set to 'No Data', for instance) the built-in ENVI statistics still ...
- 21
0
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0
answers
45
views
What is the efficient way to find the top-most images of a Landsat-8 mosaic with latest data on top?
I'm building a simple mosaic of Landsat-8 for a region of interest (a bounding box) for a time period, so that the latest data would be put on top of the mosaic. I've found 100 scenes with cloud cover ...
- 938
2
votes
1
answer
450
views
Landsat Collection 1 Level-1 or Landsat Collection 1 Higher Level?
I want to use NDWI and NDVI index in my study for a time-series analysis using all products available (Landsat 5,7 and 8).
Can I use the product Landsat Collection 1 Level 1 for my analysis or
...
- 41
2
votes
0
answers
314
views
ESPA-API for Landsat scene downloads
I've been trying to automatically download Landsat scenes with espa-api ( https://github.com/USGS-EROS/espa-api)
However I'm having a big issue with this api right now, that is the long waiting time ...
3
votes
1
answer
868
views
Better NDVI for Landsat 8?
I'm looking at NDVI changes for an area over 20 years. There seems to be a slight downward trend, however, upon switching from Landsat 5 in 2011 to Landsat 8 in 2013 I'm getting NDVI values that are ...
- 147
0
votes
1
answer
282
views
Incorrect values of NDSI index after TOA correction
I would like to calculate NDSI index (Normalized-Difference Snow Index) which basically is the same as NDVI but presents snow not vegetation :). As in NDVI the range of values for NDSI should be <-...
- 5
2
votes
1
answer
365
views
Landsat 8 reflectance values very low
I am getting very low reflectance values (mostly < 0.1) in Landsat 8 bands 2-7 on different scenes after rescaling from Digital Numbers (DN) to Reflectance. All scenes are in a tropical landscape ...
- 63
0
votes
1
answer
227
views
Why do Landsat 8 grayscales have a range of (0, 2^16-1) while the screen colors are (0, 2^8-1)?
The grayscale levels in Landsat(0-65535) are more than that can be displayed on a standard display screen(0-255). The use of Landsat reflectance values must be more than just display purposes, which ...
8
votes
1
answer
2k
views
Error installing landsat-util on Linux
I'm trying to install landsat-util on Ubuntu 16.04. I'm running Ubuntu as a virtual machine inside of Windows. I'm using a clean installation (with no packages installed) in hopes of avoiding any ...
2
votes
2
answers
451
views
Comparability of Landsats
I have collected data (spectral bands) from Landsat 4-5 and Landsat 8. I was calculating NDVI when I noticed that the two Landsats have different band numbers designated as Red and Near Infra Red (...
- 736
2
votes
0
answers
200
views
Layer Stack 6 Landsat8 bands
I have 6 images from Landsat 8 (Green,Red,NIR,SWIR1,SWIR2,NDVI). When I want to layerstack them with "Merge" I always get a result tif which is just black and white, however I can see that all 6 bands ...
- 173
2
votes
0
answers
437
views
Right Orfeo Toolbox Segmentation input
I made this tutorial. I used Landsat 8 bands (1-7), which I atmospheric corrected with DOS and converted to 8-bit. After that I layer stacked the pre processed band (1-7), clipped a little part with a ...
- 173