28
votes
Accepted
Reading, modifying and writing a geotiff with GDAL in python
Your script is missing the ds.FlushCache method, that saves to disk what you have in memory at the end of the modifications. See below a corrected version of your example. Notice that I also added two ...
- 745
16
votes
Accepted
LS7 filling the gaps image with Google Earth Engine
You could try filling the gaps before you aggregate them by month.
USGS published a LS7 SLC-off gap-filling algorithm.
This algorithm was recreated for Google Earth Engine by Noel Gorelick: https://...
- 9,947
14
votes
Writing code for monthly NDVI medians in Google Earth Engine?
For the record, here is a good way to do this:
var imageCollection = ee.ImageCollection("LANDSAT/LT05/C01/T1");
var months = ee.List.sequence(1, 12);
var composites = ee.ImageCollection.fromImages(...
- 4,369
12
votes
Filtering Landsat images base on cloud cover over region of interest
It's going to be something like this, but you'll need to play with the threshold (10 in this example) to meet your needs. Watch out for ROIs that overlap a scene's footprint, but do not contain any ...
- 4,369
10
votes
Accepted
Landsat images with bad quality
The Scan Line Corrector in the ETM+ instrument onboard Landsat-7 suffered a (suspected) mechanical failure in 2003, so all subsequent images suffer from the striping you are seeing in your images. The ...
- 10.7k
10
votes
Add bands' name and description to the Metadata when stacking using rasterio
If using rasterio >= 1.0, use the dataset.set_band_description(self, bidx, value) method and dataset.descriptions property.
Sets the description of a dataset band.
Parameters
----------
bidx : int
...
- 69.6k
9
votes
Accepted
Remote Sensing Landsat Surface Reflectance and Albedo
The Landsat reflectance data you downloaded from USGS has been scaled using a scale factor of 0.0001. So multiplying the digital number by 0.0001 will give you a value between 0 and 1. The 2000 value ...
- 659
9
votes
Why Landsat ETM+ panchromatic band' wavelength steps over visible range?
A major reason for having panchromatic bands covering a broad spectral range is a technical reason: most of the solar energy reflected by the Earth is in the NIR wavelength. As the aim of a single ...
- 49.9k
9
votes
Accepted
Using cloud confidence to create cloud mask from Landsat 8 BQA?
Here is a more flexible approach that can handle dual (or larger) bit patterns. The bit shifts are performed server-side, using the ee.Image.rightShift() and ee.Image.mod() methods.
var RADIX = 2; //...
- 5,431
8
votes
Accepted
Why Landsat ETM+ panchromatic band' wavelength steps over visible range?
A brief explanation can be found in the pdf file 'Landsat 8 (L8) Data Users Handbook', available from landsat.usgs.gov.
On page 9, first paragraph, it is said:
The OLI panchromatic band, Band 8, ...
- 10.3k
8
votes
Accepted
Noisy lines in all scenes for Landsat 7?
You should read about the Landsat 7 ETM+ SLC-off data
This refers to all Landsat 7 images collected after May 31, 2003, when the Scan Line Corrector (SLC) failed. These products have data gaps, but ...
- 2,740
7
votes
Calibrating Landsat Level-1 Precision and Terrain (L1TP) corrected data?
The three sensors are all slightly different. However the OLI/TIRs setup is a marked departure from the TM/ETM+ sensors. The changes are succintly summarised by Li et al. 2013 as the:
replacing of ...
- 2,176
7
votes
Accepted
Apply cloud mask to Landsat Imagery in Google Earth Engine Python API
for i in range(start,end-1): should be for i in range(start,end+1):
Tested it, and your code works fine.
- 10.2k
6
votes
Landsat 5, 7, and 8 surface reflectance Tasseled cap
I have found these Tasseled Cap coefficients for use with Landsat Surface reflectance data.
Please refer to the source article for applicability to your work.
http://journals.plos.org/plosone/article?...
- 175
6
votes
Accepted
Is Landsat 30m resolution satellite images accurate enough to map land cover on a 40 km² watershed?
The size of the area is not the primary issue for the selection of a satellite sensor resolution. You should rather think about the size of the objects that you are mapping and their contrast with the ...
- 49.9k
6
votes
Accepted
Where and what kind of information is geographic information stored in satellite images?
The definition of the TIFF file format allows for the storage of metadata in the file with the actual image data. This could be used by photographers for example, to store the exposure and aperture ...
- 66.5k
5
votes
Mask clouds in LandSat 8 surface refletance image
The Surface Reflectance products contain a band called 'cfmask' and 'cfmask_conf'. The documentation tells you that all pixels labelled 4 in the first band are clouds. If you just want to mask clouds ...
- 9,947
5
votes
Landsat / MODIS spatio-temporal fusion: STARFM and software implementations
If you click the "Take me to the download..." button in the page you linked, it will eventually lead you to the download link for the full StarFM distribution.
Upon extracting that file, you will ...
- 241
5
votes
How to generate a collection of mosaic images by mapping over date list in Google Earth Engine
The following code creates a list of mosaic images, where each mosaic image is constructed from images of a specified time interval. Within each time interval, the "least cloudy pixel", determined by ...
- 5,431
5
votes
Accepted
Define original image ID for each pixel of Quality Mosaic in Google Earth Engine
I had the same problem when I created the 'Best Available Pixel' code (https://github.com/fitoprincipe/geebap), and I solved this way:
Add a band in which the value of every pixel is the number of ...
- 10.2k
5
votes
No Landsat across northern Australia in 1974-1977
Between 1974 and 1977 there were intermittent problems with the data recording equipment on the satellite. With limited storage capacity on the tape, delays in transmission were observed.
NASA was ...
- 1,701
5
votes
Pansharpen landsat mosaic in Google Earth Engine
You can mosaic a collection of pan-sharpened images as follows:
// Function to mask clouds using the quality band of Landsat 8.
var maskL8 = function(image) {
var qa = image.select('BQA');
/// ...
- 5,431
5
votes
Increasing spatial resolution of Landsat MSS and TM images?
You can resample the 60- and 30-meter rasters, outputting them to 15 meter pixel size to match the 15-meter rasters (don't forget to snap all of the rasters together!). However, such resampling won't ...
- 8,356
5
votes
Accepted
Google Earth Engine data extraction from imagery
Do I need to set proj to NAD83 when defining the Point geometry too: point2 = ee.Geometry.Point([lon, lat],'EPSG:4269')
Yes, you must set this to correctly interpret the coordinates.
This is the only ...
- 10.5k
5
votes
Accepted
Landsat 8 appears to be "greener" than Landsat 5?
This is a "real" pattern that has been noted by many workers (see below for two good examples) and attributed with the different spectral responses of TM/ETM+ and OLI, though other factors ...
- 1,088
5
votes
Accepted
Using scaling factor for collection 2 level 2 with Roy et al constants
To compute reflectance value using scale factor for both collections (1 and 2) use the following functions:
var col1_DN = ee.ImageCollection("LANDSAT/LE07/C01/T2_SR");
var col2_DN = ee....
- 13.8k
5
votes
Accepted
How to make a cloud-free composite for Landsat 8 Collection 2 surface reflectance in Earth Engine
The Landsat Collection 2 surface reflectance images include a quality assessment band ("QA_PIXEL") that is derived from the CFMask algorithm. It identifies clouds, cloud shadows, and snow/...
- 6,233
5
votes
Accepted
(GEE) Constant value in Chart after applying scaling factor to LANDSAT
According to the chart, you seem to be getting a constant value. But that's not true. If you limit the axis, you will see the result clearly. To limit the axis, add viewWindow: {min: -0.20001, max: -0....
- 78k
5
votes
Pansharpen a Landsat TM 4-5 image in QGIS
No, Landsat 4 and 5 did not carry a panchromatic sensor with 15m resolution.
Sources:
https://www.usgs.gov/landsat-missions/landsat-4
https://earth.esa.int/eogateway/instruments/thematic-mapper-tm-
- 11.3k
5
votes
Accepted
Unable to map land surface temperature in QGIS from downloaded tiff
Check the thumbnails and the metadata before you download.
You've downloaded a tile that contains only a tiny amount of data in the bottom corner from the edge of a Landsat path. If you want data for ...
- 69.6k
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