Subject: Marine Geospatial Ecology Tools (MGET) help
Text archives
| From: | Jason Roberts <> |
|---|---|
| To: | Nicholas Flanders <>, |
| Subject: | Re: [mget-help] better spatial resolution SST data |
| Date: | Mon, 30 Jan 2012 21:17:51 -0600 |
Hi Nick,
We're glad MGET is useful to you. I'll answer your second question first
because it is much easier.
Many of MGET's Data Products tools have a cluster of options called
Spatiotemporal Options. These allow you to specify the spatial extent of the
output rasters.
Now for the more difficult one. I'm away from the office writing on my phone
so I have to be brief. The basic problem is that none of the SST or chl
satellites fly orbits that collect data at sufficient spatial density to
allow the production of uniform grids higher than about 4 km.
For SST, you have a lot of workarounds, but none are super easy. I know of
these basic categories of alternatives:
1. GHRSST datasets. Google that acronym. These try to combine multiple
satellites' data to obtain higher resolution at global extent. Some of these
are promising but all have difficulties. None are supported in MGET's Data
Products list yet, but some may be soon and there are alternative means for
getting them.
2. NOAA CoastWatch AVHRR SST. This product has a nominal resolution of 1.47
km but is only provided for limited locations on the planet. Worse, the
images all have slight georeferencing errors and must be hand checked and
edited to be accurate. Download from NOAA CLASS website and convert to
rasters with MGET.
3. Get Level 2 data from NOAA or NASA and convert from swath format to grid
format yourself using various tools. Slow. Difficult. And may not work close
to the equator.
For chl, the last option is really your only alternative.
In sum, there is no easy, generally applicable dataset above 4 km at this
time. You should think very carefully about whether you really need higher
resolution, because it can be a LOT of work to go there. I know several
people who started out saying "sure, I'm happy to put the time in and patient
enough to overcome all the difficulties." They ended up spending too much of
their time doing data processing and too little doing ecology.
I'd be happy to discuss this Friday, Monday, or the week after that monday (I
have another trip next week.)
Best,
Jason
Nicholas Flanders
<>
wrote:
>Hey there, I am a 1st-year grad. student in the lab of Dr. Beth Gardner at
>NC State University. Daniel Dunn helped me greatly with my search for
>oceanic env. covariate data with the link to MGET, as its a great
>resource. I was wondering if there was any data product tool available
>that will create rasters for SST or chlorophyll concentration data at a
>spatial resolution better than 4km? Also, is there a way to specify a
>specific geographic area for raster creation in any of the data product
>tools? Thanks alot and all the best, sincerely, Nick Flanders.
We're glad MGET is useful to you. I'll answer your second question first
because it is much easier.
Many of MGET's Data Products tools have a cluster of options called
Spatiotemporal Options. These allow you to specify the spatial extent of the
output rasters.
Now for the more difficult one. I'm away from the office writing on my phone
so I have to be brief. The basic problem is that none of the SST or chl
satellites fly orbits that collect data at sufficient spatial density to
allow the production of uniform grids higher than about 4 km.
For SST, you have a lot of workarounds, but none are super easy. I know of
these basic categories of alternatives:
1. GHRSST datasets. Google that acronym. These try to combine multiple
satellites' data to obtain higher resolution at global extent. Some of these
are promising but all have difficulties. None are supported in MGET's Data
Products list yet, but some may be soon and there are alternative means for
getting them.
2. NOAA CoastWatch AVHRR SST. This product has a nominal resolution of 1.47
km but is only provided for limited locations on the planet. Worse, the
images all have slight georeferencing errors and must be hand checked and
edited to be accurate. Download from NOAA CLASS website and convert to
rasters with MGET.
3. Get Level 2 data from NOAA or NASA and convert from swath format to grid
format yourself using various tools. Slow. Difficult. And may not work close
to the equator.
For chl, the last option is really your only alternative.
In sum, there is no easy, generally applicable dataset above 4 km at this
time. You should think very carefully about whether you really need higher
resolution, because it can be a LOT of work to go there. I know several
people who started out saying "sure, I'm happy to put the time in and patient
enough to overcome all the difficulties." They ended up spending too much of
their time doing data processing and too little doing ecology.
I'd be happy to discuss this Friday, Monday, or the week after that monday (I
have another trip next week.)
Best,
Jason
Nicholas Flanders
<>
wrote:
>Hey there, I am a 1st-year grad. student in the lab of Dr. Beth Gardner at
>NC State University. Daniel Dunn helped me greatly with my search for
>oceanic env. covariate data with the link to MGET, as its a great
>resource. I was wondering if there was any data product tool available
>that will create rasters for SST or chlorophyll concentration data at a
>spatial resolution better than 4km? Also, is there a way to specify a
>specific geographic area for raster creation in any of the data product
>tools? Thanks alot and all the best, sincerely, Nick Flanders.
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