[gdal-dev] Dateline gap

Thu Apr 14 09:06:06 EDT 2011

Jerl,

I suggested the ps2raster way because it's one that I know well (I'm 
supposed to) but probably there is also a GDAL solution (that I don't 
know). Since ps2raster is a GMT program I suggest that you make this 
questions in the GMT list. However, since I kind of start this I'll give 
some further infos here.
Regarding the error message you got the explanation is simple. ps2raster 
takes a POSTSCRIPT file and converts it into other formats using 
ghoscript. If the ps file was created by GMT, it will detect the 
projection information stored as PS comments and use it to create a kml 
file (or geotiff btw). That means in principle ANY figure created with 
GMT and using plain geographical coordinates can be converted to KML. 
But you used ps2raster directly with the netcdf file, which is not 
possible at all. Finally, the netcdf file is a bit strange too. What are 
the coordinates?
0 512
0 512
doesn't sound like real coordinates.

Joaquim

> Hello:
>
> I'm having a hard time getting anything to work with the files I have.
>   Maybe the files need to be changed or translated?  Joaquim mentioned
> they need to be in geogs but I'm not sure how to go about checking for
> that or converting to that if need be.  I've included output from one
> of the tests I ran.  It works the same way with all my files no matter
> what the data inside is.  One thing I thought was strange was that I
> used the -A option, and in the error message it tells me to use the -A
> options.
>
> Command:
> ps2raster -A -D./tests -E720 -TG -V -W+k testNETCDF.nc
>
> Output:
> ps2raster: Processing testNETCDF.nc: Find HiResBoundingBox Error:
> /undefined in CDF
> Operand stack:
>
> Execution stack:
>     %interp_exit   .runexec2   --nostringval--   --nostringval--
> --nostringval--   2   %stopped_push   --nostringval--
> --nostringval--   --nostringval--   false   1   %stopped_push   1878
> 1   3   %oparray_pop   1877   1   3   %oparray_pop   1861   1   3
> %oparray_pop   1755   1   3   %oparray_pop   --nostringval--
> %errorexec_pop   .runexec2   --nostringval--   --nostringval--
> --nostringval--   2   %stopped_push   --nostringval--
> Dictionary stack:
>     --dict:1151/1684(ro)(G)--   --dict:0/20(G)--   --dict:70/200(L)--
> Current allocation mode is local
> Current file position is 5
> ps2raster: GMT FATAL ERROR: The file testNETCDF.nc has no BoundingBox
> in the first 20 lines or last 256 bytes. Use -A option.
>
>
> gdalinfo for netcdf:
> Driver: netCDF/Network Common Data Format
> Files: testNETCDF.nc
> Size is 512, 512
> Coordinate System is `'
> Metadata:
>    NC_GLOBAL#Conventions=COARDS
>    NC_GLOBAL#calendar=standard
>    NC_GLOBAL#comments=File
>    NC_GLOBAL#model=geos/das
>    NC_GLOBAL#center=gsfc
> Subdatasets:
>    SUBDATASET_1_NAME=NETCDF:"testNETCDF.nc":max_temp
>    SUBDATASET_1_DESC=[15x601x1201] max_temp (32-bit floating-point)
>    SUBDATASET_2_NAME=NETCDF:"testNETCDF.nc":min_temp
>    SUBDATASET_2_DESC=[15x601x1201] min_temp (32-bit floating-point)
>    SUBDATASET_3_NAME=NETCDF:"testNETCDF.nc":prcp
>    SUBDATASET_3_DESC=[15x601x1201] prcp (32-bit floating-point)
> Corner Coordinates:
> Upper Left  (    0.0,    0.0)
> Lower Left  (    0.0,  512.0)
> Upper Right (  512.0,    0.0)
> Lower Right (  512.0,  512.0)
> Center      (  256.0,  256.0)
>
> Thank you,
>
> Jerl
>
> On Tue, Apr 12, 2011 at 7:24 PM, Joaquim Luis<jluis at ualg.pt>  wrote:
>> Jerl,
>>
>> I would do that with GMT. By using ps2raster you can convert any GMT figure
>> (in geogs of course) into KML, and GMT has excellent care of date line
>> transition issues.
>>
>> Joaquim
>>
>>> Hello:
>>>
>>> I stopped by the #gdal channel on IRC to ask this question.  Thank you
>>> for the help provided there.  I thought it might be better if I asked
>>> a question here so I can better explain what's going on in one spot
>>> and not flood the channel.
>>> I understand this is a pixel center vs pixel edge issue.
>>>
>>> My ultimate goal is to get from a netCDF file to a google map overlay
>>> contour.
>>> The general steps I've taken, which work all the way up to about
>>> 178.29 then it just cuts off.
>>>
>>> netCDF ->    color-relief PNG using "gdaldem color-relief ...  "
>>> PNG ->    Geocoded PNG using "gdal_translate -a_srs EPSG:4326 -outsize
>>> 4096 4096 -a_ullr -180.25 90.25 180.25 -90.25" on the PNG (Have also
>>> tried this with just "-180 90 180 -90"
>>> PNG ->    tiles using "gdal2tiles.py -s EPSG:4326 -z 0 -n -w google" on
>>> the Geocoded PNG
>>> I guess first question, is my methodology sound?  Maybe there's a
>>> better way/tool to approach the problem.
>>>
>>> Following is the output from gdalinfo, other than that, what
>>> information might I be able to provide that could help?
>>>
>>> Thank you,
>>>
>>> Jerl
>>>
>>> gdalinfo for the source netcdf: (My apologies, I'm not certain what is
>>> relevant so I'm including most everything.)
>>>
>>> Driver: netCDF/Network Common Data Format
>>> Files: test.nc
>>> Size is 721, 361
>>> Coordinate System is `'
>>> Origin = (-180.250000000000000,90.250000000000000)
>>> Pixel Size = (0.500000000000000,-0.500000000000000)
>>> Metadata:
>>>    NC_GLOBAL#Conventions=CF-1.0
>>>    NC_GLOBAL#cdm_data_type=GRID
>>>    NC_GLOBAL#file_format=GEMPAK
>>>    NC_GLOBAL#location=test.grd
>>>    NC_GLOBAL#history=Direct read of GEMPAK into NetCDF-Java 4.0 API
>>>    NC_GLOBAL#_CoordinateModelRunDate=2011-04-12T00:00:00Z
>>>    UVIN_NONE#long_name=testdata
>>>    UVIN_NONE#units=
>>>    UVIN_NONE#missing_value=-9.999000e+03
>>>    UVIN_NONE#VectorComponentFlag=gridRelative
>>>    time#long_name=forecast time
>>>    time#units=minute since 2011-04-12T00:00:00Z
>>>    time#_CoordinateAxisType=Time
>>>    lat#units=degrees_north
>>>    lat#long_name=latitude coordinate
>>>    lat#standard_name=latitude
>>>    lat#grid_spacing=0.5 degrees_north
>>>    lat#_CoordinateAxisType=Lat
>>>    lon#units=degrees_east
>>>    lon#long_name=longitude coordinate
>>>    lon#standard_name=longitude
>>>    lon#grid_spacing=0.5 degrees_east
>>>    lon#_CoordinateAxisType=Lon
>>> Corner Coordinates:
>>> Upper Left  (-180.2500000,  90.2500000)
>>> Lower Left  (-180.2500000, -90.2500000)
>>> Upper Right ( 180.2500000,  90.2500000)
>>> Lower Right ( 180.2500000, -90.2500000)
>>> Center      (   0.0000000,   0.0000000)
>>>
>>> gdalinfo of geocoded PNG:
>>>
>>> Driver: PNG/Portable Network Graphics
>>> Files: testWorld.png
>>>         testWorld.png.aux.xml
>>> Size is 4096, 4096
>>> Coordinate System is:
>>> GEOGCS["WGS 84",
>>>      DATUM["WGS_1984",
>>>          SPHEROID["WGS 84",6378137,298.257223563,
>>>              AUTHORITY["EPSG","7030"]],
>>>          AUTHORITY["EPSG","6326"]],
>>>      PRIMEM["Greenwich",0,
>>>          AUTHORITY["EPSG","8901"]],
>>>      UNIT["degree",0.01745329251994328,
>>>          AUTHORITY["EPSG","9122"]],
>>>      AUTHORITY["EPSG","4326"]]
>>> Origin = (-180.000000000000000,90.000000000000000)
>>> Pixel Size = (0.087890625000000,-0.043945312500000)
>>> Image Structure Metadata:
>>>    INTERLEAVE=PIXEL
>>> Corner Coordinates:
>>> Upper Left  (-180.0000000,  90.0000000) (180d 0'0.00"W, 90d 0'0.00"N)
>>> Lower Left  (-180.0000000, -90.0000000) (180d 0'0.00"W, 90d 0'0.00"S)
>>> Upper Right ( 180.0000000,  90.0000000) (180d 0'0.00"E, 90d 0'0.00"N)
>>> Lower Right ( 180.0000000, -90.0000000) (180d 0'0.00"E, 90d 0'0.00"S)
>>> Center      (   0.0000000,   0.0000000) (  0d 0'0.01"E,  0d 0'0.01"N)
>>> Band 1 Block=4096x1 Type=Byte, ColorInterp=Red
>>>    Mask Flags: PER_DATASET ALPHA
>>> Band 2 Block=4096x1 Type=Byte, ColorInterp=Green
>>>    Mask Flags: PER_DATASET ALPHA
>>> Band 3 Block=4096x1 Type=Byte, ColorInterp=Blue
>>>    Mask Flags: PER_DATASET ALPHA
>>> Band 4 Block=4096x1 Type=Byte, ColorInterp=Alpha
>>>
>>>
>>>
>>
>
>