[Met_help] [rt.rap.ucar.edu #81892] History for Question about Polylines

[John Halley Gotway via RT]

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  Initial Request
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I have a general question about the polylines used in the gen_vx_mask tool.
I was curious how you generated the lat/lon pairs for your CONUS example.
For our NWS QPF project we have GIS shape files for CONUS, individual
WFO's, River Forecast Centers, etc. But if gen_vx_mask requires lat/lon
pairs, we would have to extract those from the shape files to be used for
the masking. Have shape files been applied in gen_vx_mask?

Thanks in advance......Brad Diehl


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  Complete Ticket History
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Subject: Question about Polylines
From: Brad Diehl - NOAA Federal
Time: Wed Sep 06 09:20:31 2017

As a followup, I did some searching and found that its possible to
convert
shape files to netcdf via ogr2ogr, is that a viable method to generate
a
mask netcdf file? Has this been done before?    Thanks, Brad

On Wed, Sep 6, 2017 at 2:45 PM, met_help at ucar.edu via RT
<met_help at ucar.edu>
wrote:

> NOTE: THE MET TEAM HAS LIMITED AVAILABILITY BETWEEN 5/23/17 AND
5/30/17.
> RESPONSES MAY BE DELAYED.
>
> Greetings,
>
> This message has been automatically generated in response to the
> creation of a trouble ticket regarding:
>         "Question about Polylines",
> a summary of which appears below.
>
> There is no need to reply to this message right now.  Your ticket
has been
> assigned an ID of [rt.rap.ucar.edu #81892].
>
> Please include the string:
>
>          [rt.rap.ucar.edu #81892]
>
> in the subject line of all future correspondence about this issue.
To do
> so,
> you may reply to this message.
>
>                         Thank you,
>                         met_help at ucar.edu
>
>
-------------------------------------------------------------------------
> I have a general question about the polylines used in the
gen_vx_mask tool.
> I was curious how you generated the lat/lon pairs for your CONUS
example.
> For our NWS QPF project we have GIS shape files for CONUS,
individual
> WFO's, River Forecast Centers, etc. But if gen_vx_mask requires
lat/lon
> pairs, we would have to extract those from the shape files to be
used for
> the masking. Have shape files been applied in gen_vx_mask?
>
> Thanks in advance......Brad Diehl
>
>

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Subject: Question about Polylines
From: John Halley Gotway
Time: Wed Sep 06 12:07:38 2017

Hi Brad,

I see you have a question about defining lat/lon polylines for use in
MET.

First, I should say that ideally MET would support shapefiles
directly.  It
would be much more convenient if it could read shapefiles and use them
to
define masking regions.  We have a development task defined to do
exactly
that but don't have a project that needs this functionality and could
pay
for the development.

In the past, we have taken shapefiles and, through a handful of steps,
have
converted them into lat/lon format.  In fact, wherever you have MET
installed, take a look in met-6.0/share/met/map/admin_by_country.
This is
lat/lon map data which is very similar to the lat/lon polyline format.
I
converted this from GIS shapefiles.  And the utilities I used actually
exist as developer utilities in the MET repository, but are not
distributed
publicly.

One issue that makes things messy is that areas in shapefiles can
consists
of multiple pieces.  The polylines in MET are expected to be closed
contours.

Back in 2010, we participated in the Hydromet West testbed and for
that I
generated the CNRFC polyline region, as well as the smaller HUC
regions.
Since it consisted of multiple "pieces" I had to apply logic to group
them
together and take their union.

If you'd like, you could post the RFC shapefiles you have to the DTC's
anonymous ftp site, and I could see how helpful the developer
utilities
would be in converting them to ascii.

Alternatively, having them in NetCDF format may work as well.  You
could
also post the NetCDF output you have and I could recommend if/how it
could
be used in MET.

http://www.dtcenter.org/met/users/support/met_help.php#ftp

Thanks,
John


On Wed, Sep 6, 2017 at 9:20 AM, Brad Diehl - NOAA Federal via RT <
met_help at ucar.edu> wrote:

>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=81892 >
>
> As a followup, I did some searching and found that its possible to
convert
> shape files to netcdf via ogr2ogr, is that a viable method to
generate a
> mask netcdf file? Has this been done before?    Thanks, Brad
>
> On Wed, Sep 6, 2017 at 2:45 PM, met_help at ucar.edu via RT <
> met_help at ucar.edu>
> wrote:
>
> > NOTE: THE MET TEAM HAS LIMITED AVAILABILITY BETWEEN 5/23/17 AND
5/30/17.
> > RESPONSES MAY BE DELAYED.
> >
> > Greetings,
> >
> > This message has been automatically generated in response to the
> > creation of a trouble ticket regarding:
> >         "Question about Polylines",
> > a summary of which appears below.
> >
> > There is no need to reply to this message right now.  Your ticket
has
> been
> > assigned an ID of [rt.rap.ucar.edu #81892].
> >
> > Please include the string:
> >
> >          [rt.rap.ucar.edu #81892]
> >
> > in the subject line of all future correspondence about this issue.
To do
> > so,
> > you may reply to this message.
> >
> >                         Thank you,
> >                         met_help at ucar.edu
> >
> > ------------------------------------------------------------
> -------------
> > I have a general question about the polylines used in the
gen_vx_mask
> tool.
> > I was curious how you generated the lat/lon pairs for your CONUS
example.
> > For our NWS QPF project we have GIS shape files for CONUS,
individual
> > WFO's, River Forecast Centers, etc. But if gen_vx_mask requires
lat/lon
> > pairs, we would have to extract those from the shape files to be
used for
> > the masking. Have shape files been applied in gen_vx_mask?
> >
> > Thanks in advance......Brad Diehl
> >
> >
>
>

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