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20021002: searching for map background
- Subject: 20021002: searching for map background
- Date: Thu, 03 Oct 2002 13:37:34 -0600
Ken,
In $GEMMAPS/programs, type:
make gsfssf
That will compile the gsfssf.f program and link against
the required GEMPAK libraries.
Once you have built the program, you should be able to convert the binary
gsf file to an ascii ssf file like:
% gsfssf
Enter name of GSF map file to be converted:
../locwa.nws
Enter name of SSF map file to be created:
testme.ssf
NMBLK = 168
I'll include the mapfiles.doc description for you that describes the
gempak map file.
Steve Chiswell
Unidata User Support
GEMPAK MAP FILES
GEMPAK map files are stored as direct access, packed binary files in
a GEMPAK Standard Format (GSF). This form was chosen for compactness
and relatively rapid access.
In addition, a Sequential Standard Format (SSF) is defined for storing
maps as ASCII sequential files. SSF files are used to create new maps,
edit existing map files and transfer map files between computer
systems. Since these are ASCII files, they may be created or changed
using a text editor. The SSF files use the same format as the NCAR
sequential map file.
In both the GSF and SSF formats, latitude and longitude are given in
degrees. West longitude is negative; all longitudes must be between
-180 and +180 degrees. No map segment should cross the International
Date Line.
FORMAT OF THE SSF FILE:
An SSF file contains map segments, each of which has a series of
latitude / longitude points to be connected when the map is drawn.
Each segment contains the following information:
NP2 INTEGER Number of points (np) * 2
RMXLT REAL Maximum latitude in segment
RMNLT REAL Minimum latitude in segment
RMXLN REAL Maximum longitude in segment
RMNLN REAL Minimum longitude in segment
PTS (NP2) REAL LAT1 LON1 ... LATnp LONnp
These segments are written and read with the FORTRAN format statement:
FORMAT ( I4, 14X, 6F9.3, 8X, / ( 8F9.3, 8X ) )
The maximum number of points which may be contained in any segment
is 3000.
FORMAT OF THE GSF FILE:
These files are direct access file with a recordsize of 128 words.
The data is written in blocks of two records or 256 words. The first
block is the file header, followed by data blocks. Map segments are
packed into the data blocks; no map segment spans blocks.
The file header has 181 INTEGER*2 words containing:
NMBLK INTEGER*2 Total number of blocks
LATPTR1 INTEGER*2 Latitude pointer for 90 degrees
LATPTR2 INTEGER*2 Latitude pointer for 89 degrees
...
LATPTR180 INTEGER*2 Latitude pointer for -89 degrees
The GSF files are sorted by maximum latitude. The LATPTR array
contains the first block to use given the maximum latitude on the
plot.
These INTEGER*2 values may be changed to INTEGER*4 if required.
However, the changes must be made in the programs GSFSSF and SSFGSF
described below, as well as in GDRMAP which is the GEMPLT subroutine
used to draw maps.
The data blocks contain only 4-byte integer or real words. Each
data block contains:
NMSEG INTEGER Number of segments
----- ------ Unused
NP1 INTEGER Number of points in segment 1
RMNLT1 REAL Minimum latitude
RMNLN1 REAL Minimum longitude
RMXLT1 REAL Maximum latitude
RMXLN1 REAL Maximum longitude
----- ------ Unused
RLAT1 (1) REAL Latitude of point 1
RLON1 (1) REAL Longitude of point 1
...
RLAT1 (np1) REAL Latitude of point np1
RLON1 (np1) REAL Longitude of point np1
NP2 INTEGER Number of points in segment 2
RMNLT1 REAL Minimum latitude
...
CONVERTING A GSF TO AN SSF FILE:
The program GSFSSF, which is in $GEMMAPS/programs, can be used to
convert any GSF file to an SSF file. The user is prompted for the
existing GSF file name and a name for the SSF file to be created.
CONVERTING AN SSF FILE TO A GSF FILE:
The program SSFGSF, also in $GEMMAPS/programs, can be used to convert
an SSF file to a GSF file. The user is prompted for the existing SSF
file name and a name for the GSF file to be created. The user can also
enter a latitude / longitude window to subset the data. Any points
outside the window will be eliminated from the output file. However,
no clipping is done. The minimum and maximum latitude and longitude
stored with each segment will be recomputed internally, so the
values in the SSF file need not be correct. The intermediate files,
DAFIL.INT and SEQFIL.INT, are used by the program and may be deleted
after completion.
NAMING CONVENTIONS FOR GEMPAK MAP FILES:
The map files are named by concatenating the resolution, map
boundaries, and area with the three-letter source file type. For
example, the medium-resolution political world map from Goddard
Space Flight Center is called MEPOWO.GSF.
RESOLUTION FEATURES AREA SOURCE
ToP POlitical WOrld GSFc
HIgh COastline NW quadrant NWS
MEdium REgional NE quadrant CIA
LOw CouNty SE quadrant USGeol survey
MiXed CountrY SW quadrant NCeP
RiVers North Hemisphere RFC
InterState highways South Hemisphere CPC
U.s. Highways US
State Highways Us Oceans
RoaDs North America
River Forecast Cntrs Atlantic North
County Watch Areas Atlantic1
ZoNes Atlantic2
High Seas Atlantic3
OffShore Pacific North
Forecast Bounds Pacific East
AViation Pacific Surface
Flight Info region Pacific1
Convective Sigmet Reg Pacific2
Tpc High seas Pacific3
Tpc Sigmets MarylanD
Tpc surface Bounds Basic Weather
Tpc surface Analysis Medium Range
Tpc aViation bounds Qpf Verification
Continental Divide Western Region
Mar pred ctr Offshore Arkansas-Red Basin
River fcst ctr Basins Lower Mississippi
Climate Zones Middle Atlantic
Palmer climate Zones Missouri Basin
STates North Central
LaKes NorthEast
OHio
SouthEast
West Gulf
AlasKa
The maps from GSFC were obtained for GEMPAK Version 1.0. The history
of these maps is unknown. The CIA map files were created from a
subset of the CIA map database. The United States Geological Survey
maps were converted from the USGS databases. The NWS maps were
obtained from the NWS/Modernization Systems Implementation Group. The
NCEP map files were developed at the NWS/National Centers for
Environmental Prediction. The RFC map files were provided by the
Arkansas-Red Basin River Forecast Center.
There are 5 maps designed to be used for the seamless surface analysis
which shows the area of responsibility for the Tropical Prediction
Center, Marine Prediction Center and the Hydrometeorological Prediction
Center. Also, these maps have the numbers 050 and 215 in their names
which refer to the amount of time after the analysis time; 50 minutes
past and 2 hours and 15 minutes past the analysis time.
CIA MAP FILE WITH NAMES:
A subset of the CIA map database which has a geographical name attached
to each record is included in the complement of GEMPAK maps. The names
in this file were originally added by Joseph Fulson-Woytek at Goddard
Space Flight Center. The map file name is: cia.nam.
The program NAMSSF is included to convert a subset of this database
into a sequential format file (SSF). The program will prompt for the
following inputs:
AREA: This may be any geographic name or a range of
records specified by the start and stop records separated
with a "-".
REGION: A character string listing the regions to be used (a
blank defaults to all) where the valid regions are:
C - Continental borders
I - Islands
L - Lakes
S - State borders
N - National borders
R - Rivers
T - Tectonic plates
M - Miscellaneous
Example: Create a map containing only Mexico borders
AREA: mexico
REGION: cn
Note that adding S will include "New Mexico" and I will
include "Gulf of Mexico Islands".
The program NAMPLT will plot individual records listing the record
and waiting for a <CR> after each record. This can be used for
debugging the map file. GPMAP must be run first to select the
graphics area and device.
The files doc.nam and rec.nam include the detailed documentation
and a list of records for the map elements, respectively. If changes
are made to the data base, they should be returned to the GEMPAK
developers in order to be included in the original dataset from which
the map file was created.
>From: Ken Scheeringa <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200210031913.g93JD8103179
>
>Steve,
>
>I found the source file gsfssf.f
>and the map files locosh.gsf and loconh.gsf
>which I am guessing is what I want.
>
>How do you install gsfssf?
>
>I found just compiling the Fortran source
>doesn't do it and neither does gsfssf_link.
>I am probably missing some steps.
>
>If I can't get it to go I still may come back
>to you for the pre-compiled version on AIX.
>
>
>On Thu, 3 Oct 2002, Unidata Support wrote:
>
>>
>> Ken,
>>
>> I generally don't include the ascii data bases that the GEMPAK maps
>> are generated from since they add space to the distribution tarfile.
>> But, they can be generated using the gsfssf program which
>> can be built in the $GEMMAPS/programs directory if you have the source
>> distribution..
>>
>> I can either post the ascii map file, or a binary of gsfssf
>> otherwise.
>>
>> Steve Chiswell
>>
>>
>>
>>
>>
>>
>> >From: Ken Scheeringa <address@hidden>
>> >Organization: UCAR/Unidata
>> >Keywords: 200210030352.g933q5124507
>>
>> >Hello support,
>> >
>> >I am trying to locate a file of digital coordinates
>> >which defines the continental boundaries for each of
>> >the northern and southern hemispheres in a polar
>> >projection.
>> >
>> >For example, when the coordinates in the northern
>> >hemisphere file are connected in sequence, the resulting
>> >map background would reproduce the old DIFAX
>> >500 mb hemispheric (polar projection) chart geography
>> >before any data are added.
>> >
>> >I searched my GEMPAK map background folders but I
>> >believe all these coordinates are stored in binary format.
>> >I am seeking an ASCII coordinate file which could be
>> >used as well in other software I am writing.
>> >
>> >Any sources of such map background files that you
>> >are aware of that I could obtain would be most appreciated.
>> >
>> >Thanks very much for assistance.
>> >
>> >
>> >***************************************************************************
> ***
>> > *
>> >Ken Scheeringa Indiana Climate Page
>> >State Climatologist http://shadow.agry.purdue.edu
>> >Agronomy Dept
>> >Purdue University featuring climate data archives:
>> >e-mail: address@hidden daily coop stations : 1994+
>> >fax: 765.496.2926 hourly airport data : Jul 1996+
>> >phone: 765.494.8105 30-min autostation : 1999+
>> > updated daily
>> > Also monthly/daily normals
>> >***************************************************************************
> ***
>> > *
>> >
>>
>> ****************************************************************************
>> Unidata User Support UCAR Unidata Program
>> (303)497-8643 P.O. Box 3000
>> address@hidden Boulder, CO 80307
>> ----------------------------------------------------------------------------
>> Unidata WWW Service http://www.unidata.ucar.edu/
>> ****************************************************************************
>>
>
>******************************************************************************
> *
>Ken Scheeringa Indiana Climate Page
>State Climatologist http://shadow.agry.purdue.edu
>Agronomy Dept
>Purdue University featuring climate data archives:
>e-mail: address@hidden daily coop stations : 1994+
>fax: 765.496.2926 hourly airport data : Jul 1996+
>phone: 765.494.8105 30-min autostation : 1999+
> updated daily
> Also monthly/daily normals
>******************************************************************************
> *
>