25
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 ...
- 715
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://...
- 9,806
14
votes
Accepted
Is the reflectance required to get the NDVI, for Landsat 8 images?
NDVI is defined for any two bands with near-infrared and infrared data (it is an empirical remote sensing index). As such, you can calculate it straight from the DNs. This is mostly OK if you are only ...
- 1,304
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(...
- 4,329
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 ...
- 4,329
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
...
- 64.9k
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 ...
- 49.4k
8
votes
Tutorial Vegetation Condition Index
Kogan (2004) (p. 2891) provides the following formula for the Vegetation Condition Index (VCI):
VCI = 100 * (NDVI - NDVImin) / (NDVImax - NDVImin)
where,
NDVI = Smoothed weekly NDVI value
NDVImin ...
- 51.5k
8
votes
Accepted
Error installing landsat-util on Linux
gnutls.h which is required is missing from the filesystem even if you install libcurl4-gnutls-dev which supposedly has the headers files for curl.
to correct for that error run:
# apt-get install ...
- 11.5k
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, ...
- 10.2k
8
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; //...
- 5,371
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 ...
- 2,737
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 ...
- 2,156
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.
- 9,985
6
votes
Accepted
Classify forest with NDVI from Landsat 8 and 7
No, the NDVI threshold value will not be the same for the time series due to differences in phenology and unique conditions on the ground. As Kersten mentioned in the comments, you may want to ...
- 51.5k
6
votes
Pan sharpening of SPOT and Landsat images
Pan sharpening is a well documented image processing technique and you will find bunch of HowTo's and tools in the web (GDAL, ArcGIS, Orfeo TB, Grass, ENVI).
On a common data oriented processing ...
- 3,518
6
votes
Accepted
Difference between Landsat 7 and Landsat 8 TOA reflectance computation
The two products are comparable with some initial considerations. As you can see, the resolutions of the products are more or less the same:
To give a more visual comparison of the spectral bands ...
- 4,578
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 ...
- 49.4k
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 ...
- 62.6k
5
votes
Atmospheric correction of Landsat images
Atmospheric correction means removing absorption effects of e.g. water vapor and aerosols from the image. This can be done if you know the gas/aerosol concentration and their absorption properties for ...
- 891
5
votes
Is LANDSAT 8 Resolution too low for coastline difference measurement?
30m - 45m is a lot of change in a coastline over one year and only very dynamic areas see that kind of change rate. As such, you are correct in your assessment of the impact of imagery resolution on ...
- 6,486
5
votes
Accepted
Landsat 5 RGB image looks very dark in QGIS
This is normally due to poor colour rendering.
Try adjusting the Contrast enhancement option in layer properties. "Stretch to MinMax" is a good default
Also decrease the max value for each band/ ...
- 534
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 ...
- 9,806
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 ...
- 221
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 ...
- 5,371
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 ...
- 9,985
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 ...
- 1,725
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