Dear Soeren and Luca,
First, let me introduce myself again to Soeren. My name is Bo Yang, a Ph. D.
student in the Department of Geography, University of Cincinnati, OH, USA. I
have a bachelor degree in Mathematics and MS in Computer Science. I am really
interested in OSGeo-SoC2016. It would be a great opportunity if I can make
contributions as well as learn to become an open-source developer.
Currently I have an idea based on my MA thesis project: Spatio-temporal fusion
of multi-scale data with in a cokriging framework.
This project extends traditional cokriging method for blending spatial data
sets with different temporal sampling frequency and spatial resolution
(density). It can be used for both raster data and vector data, effectively
fill in data gaps due to severe weather condition, instrument malfunction, or
other reasons, filtering out data noise, and generate reliable results at both
high spatial resolution and high temporal frequency with associated uncertainty
estimates.
Soeren, I noticed you are the author of r.series.interp. I discussed a little
with Luca, I agree this project is highly related to the package. So I am
writing to ask if you are interest in mentoring this project. Currently I have
the preliminary python code for the raster fusion attached(ImageFusion_SoC.py).
It was written during my master degree, so it is sort of rough and haven't been
re-constructed to OOP yet. But it runs well for fusion MODIS and Landsat data.
I attached an fusion example for NDVI[0] images. The program is able to blend
Landsat TM/ETM+ NDVI image (30m) with MODIS NDVI image (250m)[1]. The NDVI can
be calculated from the combination of the red band (Band 3 of Landsat TM or
ETM+ multispectral imagery, or Band 1 of MODIS multispectral imagery) and near
infrared band (Band 4 of Landsat TM or ETM+ multispectral imagery, or Band 2 of
MODIS multispectral imagery). MODIS data has been resampled to 270m to
co-registered with Landsat pixels.
I selected a relatively cloud free period (07/19/2002-07/29/2002) to
demonstrate the fusion process, the study region is Lake Tahoe region, NV, USA.
Both Landsat and MODIS NDVI images need to be converted to ASCII file, source
data can be found here[2]. Text files start with "A" are daily MODIS NDVI
images and "lt5ndvi_0716" is the Landsat TM data. The goal of this example is
to fuse daily MODIS NDVI images with a Landsat NDVI images (30m) to generate
images at 30 m spatial resolution for everyday, using spatio-temporal cokriging
method. Namely, I intend to use a single high resolutions Landsat NDVI images
to sharpen daily time series MODIS images. Also the program is able to fill in
the missing value. I artificially generated a missing data region in each input
MODIS image and we can see the result fill in the missing data region very
well. One good application of this algorithm is to fill in the gaps in the
Landsat ETM+ images after 2002 due to the sensor's malfunction.
The fusion module is attached, it need an input exponential/Gaussian model
parameter which was calculated via semi-variogram fitting module. I did export
the parameters in the attached text file for this case so the fusion module can
be run independently. To run the program quickly, just put attached text file
and source data[2] in the working folder and apply it to line22 of the fusion
module. Of course other MODIS data can be used for this program if converted to
ASCII files. There are two fusion methods, first one (line 330:
fusion_with_covariable) is used for the MODIS data, which can sharpening and
fill-in the missing data values. Second one is cokriging which incorporated the
fine Landsat image as co-variable, it can achieve much better sharpening result
as well as fill-in missing data values. Both method generated the gap filled
result at 30m spatial resolution.
Please let me know if you have and comments or suggestions. Luca, thank you for
sending me the compile method and programming manual. I normally used windows
OS, and Eclipse + Pydev as primary IDE. I am going to look into the manual and
GRASS codes. Any more advice would be greatly appreciated.
Best regards,
Bo Yang
[0] https://en.wikipedia.org/wiki/Normalized_Difference_Vegetation_Index
[1] https://lpdaac.usgs.gov/dataset_discovery/modis/modis_products_table/mod09gq
[2]
https://drive.google.com/folderview?id=0B25sQdmthpGJS0JOdEh5cDd4S1k=sharing
-Original Message-
From: Luca Delucchi [mailto:lucadel...@gmail.com]
Sent: Wednesday, March 16, 2016 11:18 AM
To: Yang, Bo (yangb2) ; Sören Gebbert
Cc: grass-dev@lists.osgeo.org
Subject: Re: [GRASS-dev] OSGeo-SoC 2016 application
On 16 March 2016 at 04:49, Yang, Bo (yangb2) wrote:
> Hi Luca,
>
Hi Bo Yang,
> Thank you for the reply and info. It is great if you could co-mentor this
> project. I would be more interest in implementing my spatio-temporal fusion