[GRASS-user] trouble with r.in.gdal to georeference a NetCDF file

[Lee Eddington]

Markus,

I can read a raster from the file into GRASS using:

r.in.gdal input="NETCDF:test.nc:V10" output="V10_test3"

and I get the following:

GRASS 6.4.3 (bali_d03):~ > r.info V10_test3
 +----------------------------------------------------------------------------+
 | Layer:    V10_test3                      Date: Sat Nov 23 20:56:28 2013    |
 | Mapset:   PERMANENT                      Login of Creator: Lee             |
 | Location: bali_d03                                                         |
 | DataBase: /Users/Lee/grassdata                                             |
 | Title:     ( V10_test3 )                                                   |
 | Timestamp: none                                                            |
 |----------------------------------------------------------------------------|
 |                                                                            |
 |   Type of Map:  raster               Number of Categories: 255             |
 |   Data Type:    FCELL                                                      |
 |   Rows:         153                                                        |
 |   Columns:      198                                                        |
 |   Total Cells:  30294                                                      |
 |        Projection: x,y                                                     |
 |            N:        153    S:          0   Res:     1                     |
 |            E:        198    W:          0   Res:     1                     |
 |   Range of data:    min = -12.64637  max = 7.255654                        |
 |                                                                            |
 |   Data Description:                                                        |
 |    generated by r.in.gdal                                                  |
 |                                                                            |
 |   Comments:                                                                |
 |    r.in.gdal input="NETCDF:test.nc:V10" output="V10_test3"                 |
 |                                                                            |
 +----------------------------------------------------------------------------+

gdalinfo on test.nc gives the following (I’ve stripped out a lot of the metadata, but left the info the describes the Mercator projection):

lees-mbp:bali Lee$ gdalinfo test.nc 
Warning 1: No UNIDATA NC_GLOBAL:Conventions attribute
Driver: netCDF/Network Common Data Format
Files: test.nc
Size is 512, 512
Coordinate System is `'
Metadata:
.
.
.
  NC_GLOBAL#CEN_LAT=-8.4095154
  NC_GLOBAL#CEN_LON=115.02
.
.
.
  NC_GLOBAL#MAP_PROJ=3
.
.
.
  NC_GLOBAL#STAND_LON=115.02
.
.
  NC_GLOBAL#TRUELAT1=-8.4095001
  NC_GLOBAL#TRUELAT2=0
.
.
.
Subdatasets:
  SUBDATASET_1_NAME=NETCDF:"test.nc":U10
  SUBDATASET_1_DESC=[1x153x198] U10 (32-bit floating-point)
  SUBDATASET_2_NAME=NETCDF:"test.nc":V10
  SUBDATASET_2_DESC=[1x153x198] V10 (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)

I can display the data in GRASS (see attachment).

I have the latitude and longitude values for every raster point from another file and can read them into collocated rasters.  I was able to interactively georectify the raster, but my goal is produce automated scripts and it doesn’t appear that there’s a way to automate the georectify process (please correct me if I’m wrong).  I tried using g.setproj to change the projection as I know what it is, but it wouldn’t allow me to because the current projection is x,y.

Thanks for sticking with me on this,

Lee


On Nov 23, 2013, at 7:43 AM, Markus Neteler <neteler at osgeo.org> wrote:

> Lee,
> 
> I am not much familiar with non-map netCDF files. I do not know how to
> deal with this specific file...
> Let's hope that an answer from the community arrives. To me it doesn't
> look like a file containing maps.
> 
> Best
> Markus
> 
> 
> On Sat, Nov 23, 2013 at 9:58 AM, Lee Eddington
> <lee.w.eddington at gmail.com> wrote:
>> Markus,
>> 
>> I tried and got the following:
>> 
>> lees-mbp:bali Lee$ gdalwarp test.nc test.tif
>> 
>> Warning 1: No UNIDATA NC_GLOBAL:Conventions attribute
>> 
>> Input file test.nc has no raster bands.
>> 
>> 
>> I've attached the file in case you'd be willing to see what you can do with
>> it.
>> 
>> Thanks,
>> Lee
>> 
>> 
>> 
>> On Sun, Nov 17, 2013 at 1:29 AM, Markus Neteler <neteler at osgeo.org> wrote:
>>> 
>>> On Wed, Nov 13, 2013 at 11:58 PM, Lee Eddington
>>> <lee.w.eddington at gmail.com> wrote:
>>>> Markus,
>>>> 
>>>> Could you provide me an example of using gdalwarp converting a NetCDF
>>>> field
>>>> to a GeoTIFF?
>>> 
>>> I often due multiple runs here. Initially
>>> 
>>> gdalwarp thefile.nc thefile.tif
>>> 
>>> then I check if the target resolution is as expected (if not, see the
>>> -tr parameter) and so on.
>>> Here is an older blog page which may be of interest:
>>> 
>>> http://blog.neteler.org/gdal-raster-data-tips-and-tricks/
>>> 
>>> Markus
>> 
>> 

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