On 6/6/2016 1:25 PM, Kurt Schwehr wrote:
+gdal-dev
Some hackish test code I had laying around from last year...
https://gist.github.com/schwehr/01f6604afc7757ea0a676f0eb28be582
Thank you! I have it running, so next I'll play with the code.
You might also be able to just write 80 layers of u-v, pick out pairs
for each depth layer and have the rendering system do the
conversion(s). You could use whatever you want once you have a
geotiff. In this screenshot, I made an 80-layer geotiff of u and v
alternating layers and uploaded that to Earth Engine. It's been a long
time since I heavily used mapserver, but you could probably do the same
there.
https://www.flickr.com/photos/schwehr/26895009754/
Very cool picture!
This really helps to get me started.
Thanks,
-Steve
On Mon, Jun 6, 2016 at 7:51 AM, Stephen Woodbridge
<wood...@swoodbridge.com <mailto:wood...@swoodbridge.com>> wrote:
On 6/5/2016 2:04 PM, Kurt Schwehr wrote:
Stephen,
Take a look at these two discussions for starters on working
with hycom:
http://gis.stackexchange.com/questions/167155/how-can-i-make-geotiffs-of-individual-depth-layers-in-the-hycom-ocean-circulatio
Hi Kurt,
In the link above you mention:
I've got some code written the does things like calculate the speed
inm/s from the UV and creates a geotiff, etc
Can you share this code, it sounds like exactly what I need for the
current vectors? And I'm interested in figuring out how to
read/write and work with the netcdf files.
I think for now I'll work with the "u" datasets as they seem that
they will be much easier place to start.
Thanks,
-Steve
http://gis.stackexchange.com/questions/170882/how-can-a-make-a-netcdf-with-subgroups-smaller
You should start with the regular grids. e.g.
ftp://ftp.hycom.org/datasets/GLBu0.08/expt_91.1/data/hindcasts/2015/hycom_glb_911_2015093000_t000_uv3z.nc
Make an 80 layer geotiff from the u/v and then use mapserver as Even
suggested.
-kurt
On Sat, Jun 4, 2016 at 6:29 AM, Even Rouault
<even.roua...@spatialys.com <mailto:even.roua...@spatialys.com>
<mailto:even.roua...@spatialys.com
<mailto:even.roua...@spatialys.com>>> wrote:
Hi,
>
> I want to convert some HYCOM data into GTiff format and
I'm a little
> lost on how to get started, whether I can do what I need
just using a
> vrt or if I'm going to have to write code to process the data.
>
> To start with I have placed gdalinfo on one file here:
> http://imaptools.com:8080/dl/hycom-gdalinfo.txt
>
> The data comes from http://hycom.org/dataserver/glb-analysis
> and I will need to be using GLBa0.08 dataset.
>
> I have two use cases:
>
> 1) The simple one is to extract say Band 1 into a
georeferenced GTiff
> and apply color to using color ranges without loosing the
NODATA. I
> think I can do later using .vrt, correct?
gdaldem color-relief can output to a VRT, but given that
this netCDF
file is
georeferenced through a geolocation array, you'll likely
have first
to run
gdalwarp -geoloc to have something useful at the end.
>
> I'm not sure how to deal with the georeferencing, because
the download
> site says: "Native hycom .[ab] data converted to NetCDF on
native
> Mercator-curvilinear HYCOM horizontal grid" but that does
not seem in
> sync with the Metadata in the file.
>
> 2) The more complicated case is that there are two files:
> a) eastward_sea_water_velocity (aka: u, u-velocity)
> b) northward_sea_water_velocity (aka: v, v-velocity)
> that I would like to use to create a grid of vectors with
arrowheads
> using u and v to define the vector and where the color of
the vector is
> related to the magnitude of its length. Ultimately this
data will get
> rendered via mapserver so I'm wondering if I can do this
via a GTiff or
> if I will have to resort to creating a massive point
shapefile with
> attributes of angle and magnitude and use a symbol. It
seems like it
> would be best if I can keep the data as a GTiff and then
sample the
> points and render the vectors on the fly for when you zoom
in/out.
See
http://mapserver.org/input/vector/vector_field.html
You don't need to create a vector file.
You'll have to preprocess your file to get the u and v bands
in the same
raster.
Even
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