19
votes
Image collection to Single Image in Google Earth Engine
// UPDATE: The easiest way is now toBands().
var merged = MOD1.toBands();
// For completeness, this is the iterate() way:
var mergeBands = function(image, previous) {
return ee.Image(previous)....
- 3,974
14
votes
Accepted
Google earth engine:SST by month per year
var sst = ee.ImageCollection('NASA/OCEANDATA/MODIS-Aqua/L3SMI')
.select('sst')
.filterDate(ee.Date('2013-01-01'), ee.Date('2017-12-31'))
var months = ee.List.sequence(1, 12);
var years = ee....
- 3,974
11
votes
Accepted
How to download MOD16 (Modis Evapotranspiration) image?
The project website hosts the MOD16 dataset on an FTP server.
As FTPs allow directory listings you can easily download complete folders without having to click individual links. This can be done with ...
- 9,400
10
votes
Accepted
Export data from time-series image collection to a table in Google Earth Engine
Here is a modification of the first example from this presentation about tables and vectors. Note that you can "transpose" the table if there are other properties in the points that are of interest:
...
- 3,974
9
votes
MOD09A1 QC layer
This is a good question, naturally isn't obvious how to handle this kind of data. For example, the product State QA has 16 bits and there are single, double and triple bit flags combinations:
For ...
- 11.7k
8
votes
Accepted
Reprojecting MODIS-Sphere ESRI GRID file to WGS84 using QGIS/GDAL
The Readme.docx inside the zip file gives some hints on the projection, but maybe misleading.
The raster is in an interrupted Goode Homolosine projection, based on the MODIS sphere.
So I created the ...
- 74.9k
8
votes
extract scientific layers from MODIS HDF Dataeset using Python GDAL
Here is my code I use to convert all HDFs in a folder to GeoTIFF via GDAL (OSGEO4w) in Windows when working with SST data. Remember to use the OSGEO4W version to get hdf support.
for %A in ("C:\temp\*...
8
votes
Accepted
Combine two collections (MOD13Q1 and MYD13Q1) from Google Earth Engine
My guess is you are trying to combine the two 16-day composites into a synthethic 8-day composite containing data from both Aqua and Terra (as has been proposed in many research papers).
You can do ...
- 9,400
8
votes
Accepted
Making stack from many images in Google Earth Engine?
You just need the function 'toBands()' and apply that on the image collection. Unfortunately, the function cannot deal with similar band names (at least, for your MODIS collection: it works fine for ...
- 9,218
7
votes
Accepted
Download MODIS data for Mexico
you can find the H and V index in all MODIS product file name. These indices refer to the grid below (from the MODIS Website). For instance you have H8V6 (MOD17A3.A2000001.h08v06.055.2011276103801.hdf)...
- 48.5k
7
votes
Accepted
Convert 800 .hdf4 files to Tiff using GRASS/QGIS/SAGA/GDAL/R
If you know R, you can use the package "gdalUtils" and run gdal_translate to do that. If you are on Linux make sure to install GDAL. If you are on Windows, you're good to go.
These are the basic ...
- 793
7
votes
Extract elevation data from Landsat / MODIS imagery?
Landsat and Modis are optical sensors, which means that they provide digital numbers of reflected materials that are within the electromagnetic spectrum. These values correspond to the wave length of ...
- 9,203
7
votes
Accepted
Is there any reason NOT to use MODIS sinusoidal projection?
Got rid of the downvote, somebody is just trolling.
I have done this with MODIS rasters without problem before, in sinusoidal, you are right, should retain the area over other projections. That ...
- 336
7
votes
Accepted
How big is a MODIS 250m pixel in reality?
Per https://lpdaac.usgs.gov/dataset_discovery/modis, the viewing swath width of MODIS is 2,330 km, thus a large portion of the image is off-nadir in some way. https://modis.gsfc.nasa.gov/about/...
- 3,596
6
votes
Accepted
How to interpret MOD44B 8-bit quality layer
I think you're misunderstanding the bit packing in the QA flags as your example with 32 is incorrect. 32 is 00100000 in binary so can only mean bad data in the 6th input (bits are numbered from right ...
- 51.7k
6
votes
Accepted
extract scientific layers from MODIS HDF Dataeset using Python GDAL
If you are working with a GDAL version that supports HDF5 datasets this is how you can extract a single subdataset from it and convert it to Geotiff in Python. This example was used for MOD09 and ...
- 9,400
6
votes
Accepted
How to tranform MODIS tiles into lat/long?
Projection of this kind of files is sinusoidal. For this one:
ftp://ladsweb.nascom.nasa.gov/allData/6/MOD13Q1/2016/129/MOD13Q1.A2016129.h07v06.006.2016147112419.hdf
the next code can access to ...
- 25.8k
6
votes
Accepted
Spatial downscaling of MODIS LST grids using a covariate (e.g. NDVI): available software?
I have used a robust regression approach, for downscaling of climate data, with consistent success. The idea is that you treat the lower-resolution data as the dependent variable, as a sample or ...
- 29.2k
6
votes
Getting tile number of sinusoidal MODIS product from lat/long?
MODIS assumes the Earth is a sphere with a R = 6.3781e6 m radius. The world is subdivided into 18 vertical tiles and 36 horizontal tiles, each tile has 2400 cells of 500m x 500m.
We can code this as:
...
- 211
6
votes
Accepted
Adding timestamp to video export in Google Earth Engine
Here is a code that I found from an answer from google-earth-engine developers group by Gennadii Donchyts:
https://code.earthengine.google.com/6270df443326ec0d90a18838bd91c5a5
Essentially, a package ...
- 654
6
votes
Merging two image collection into one with two bands (LST and NDVI )
You should show more effort and paste some code, what you have tried. But anyhow, I think this is what you want:
// Collections
var mod1 = ee.ImageCollection("MODIS/006/MOD11A2");
var mod2 = ee....
- 9,218
6
votes
Earth Engine memory capacity exceeded
The error Earth Engine memory capacity exceeded. means that Earth Engine was unable to allocate memory while computing your request. It does not necessarily mean that your script inherently requires ...
- 8,521
6
votes
Creating Cloud free images out of a MOD09A1 MODIS image in GEE?
I haven't actually worked with MODIS, but it looks like most other image collections in EE. The images contains a QA band, StateQA, with data about clouds/shadow/etc. The catalog contains a ...
- 9,280
5
votes
Accepted
How can I parse modis MOD13Q1 quality layers in R?
Just a tiny error, as far as I can see. Your substrings are incorrect. This can be seen by comparing the result from a 'which(df$bits="0000100001000100")' with a number of observed unique values, ...
- 6,378
5
votes
stack 10 modis ndvi geotiffs and scale them by 0.0001
In Windows (run OSGeo4W shell):
Scaling:
for %i in (*.tif) DO gdal_translate -scale -2000 10000 -0.2 1 %i outputs\%i
You might find recalculating instead better:
for %i in (*.tif) DO gdal_calc.bat ...
- 2,051
5
votes
Accepted
How to correctly parse MODIS QA layers?
Answer from LPDAAC:
It goes from 0000 to 1111, with 0000 being the best and 1111 worst.
For some reason the table on the product page wasn't complete.
To understand what it means and how ...
- 448
5
votes
Accepted
Reconstructing MODIS time-series applying Savitzky-Golay Filter with Python/Numpy
You need to interpolate missing data before you can apply the Savitzky-Golay filter. TIMESAT is the most widely used tool for this job and they handle missing data with linear interpolation prior to ...
- 9,400
5
votes
Reconstructing MODIS time-series applying Savitzky-Golay Filter with Python/Numpy
Based on the SG filter from scipy.signal I built the NDVI timeseries smoothing algorithm proposed in:
A simple method for reconstructing a high quality NDVI time-series data set based on the ...
- 265
5
votes
MODIS MOD11A1 Reproject Change Data Value
As mentioned in the files metadata, the modis source data has a scale factor of 0.02. QGIS applies it on-the-fly.
But the reprojection with gdalwarp destroys the scale factor information, hence the ...
- 74.9k
5
votes
How do MODIS products naming conventions work?
It represent from January 1st to January 16th. Here you got some information:
From Agricultural and Forest Meteorology 161 (2012) 15–25
The day of year (DOY) for each MODIS image represents the ...
- 11.7k
Only top scored, non community-wiki answers of a minimum length are eligible