[gdal-dev] gdal_translate: a preliminary `-gcp_file' patch

[Brent Fraser]

Ivan,

  Would using the current --optfile command line switch (see
the bottom of http://www.gdal.org/gdal_utilities.html) work?
You could try

    gdal_translate -optfile my_gcps.txt infile.hdf
outtile.tif

with  a file of "my_gcps.txt":

-gcp 0 0 10000 123456
-gcp 10 10 10200

I'm not sure how GDAL handles reading the file specified in
the --optfile, but I did use a similar technique to input
135 file names into gdal_vrtmerge.py

Brent Fraser
GeoAnalytic Inc.
Calgary, Alberta

----- Original Message ----- 
From: "Ivan Shmakov" <ivan at theory.asu.ru>
To: <gdal-dev at lists.osgeo.org>
Sent: Thursday, December 13, 2007 2:09 AM
Subject: [gdal-dev] gdal_translate: a preliminary
`-gcp_file' patch


> Since the current version of GDAL doesn't support reading
GCPs
> from some of the data sets I use [1], I have to use
> `gdal_translate' to specify all the GCPs, like:
>
> $ file=/where/is/AIRS-L2-RetStd.hdf
> $ gdal_translate \
>       $(paste <(hdfdump --text "$file" {Long,Lat}itude) \
>             | gawk '$1 != -9999 && $2 != -9999 { print
"-gcp", (NR - 1) % 30 + .5, int ((NR - 1) / 30) + .5, $1,
$2; }') \
>
"HDF4_EOS:EOS_SWATH:\"$file\":L2_Standard_atmospheric&surfac
e_product:TSurfStd" \
>       AIRS-L2-RetStd.TSurfStd.gcp.tiff
> $
>
> There, the dimensions of the data set are 30x45.
>
> However, would I try to use the above on a larger data set
(say,
> MODIS 1 km, which is 1354x2030 for a standard NASA
granule),
> I'll quickly run into the command line size limit (on most
of
> the operating systems I know.)
>
> Therefore, I suggest the new `-gcp_from FILE' option for
> `gdal_translate'.
>
> The patch is roughly as follows.  Beware that the getline
()
> function is a GNU extension, available either from GNU
Libc [2],
> or Gnulib [3].
>
> --- gdal_translate.cpp.~4~ 2007-12-13 11:32:31.000000000
+0600
> +++ gdal_translate.cpp 2007-12-13 13:57:30.000000000 +0600
> @@ -57,6 +57,7 @@
>              "       [-srcwin xoff yoff xsize ysize]
[-projwin ulx uly lrx lry]\n"
>              "       [-a_srs srs_def] [-a_ullr ulx uly lrx
lry] [-a_nodata value]\n"
>              "       [-gcp pixel line easting northing
[elevation]]*\n"
> +            "       [-gcp_from gcp_file]*\n"
>              "       [-mo \"META-TAG=VALUE\"]* [-quiet]
[-sds]\n"
>              "       [-co \"NAME=VALUE\"]*\n"
>              "       src_dataset dst_dataset\n\n" );
> @@ -79,6 +80,79 @@
>  }
>
>
/***********************************************************
*************/
> +/*                           handleGCPfrom ()
*/
>
+/**********************************************************
**************/
> +static int
> +handleGCPfrom (const char *filename, GDAL_GCP **gcpp, int
*ngcpp)
> +{
> +    /* NB: `ngcpp' should be of type `size_t *' rather
than `int *' */
> +    FILE *fp;
> +    int lineno;
> +    char *linebuf = 0;
> +    size_t linesz = 0;
> +    size_t new_points;
> +
> +    /* open the file, return -1 on failure */
> +    fp = fopen (filename, "r");
> +    if (fp == 0) {
> +        /* use strerror () here? */
> +        /* follow generic Unix ``program: message''
convention? */
> +        fprintf (stderr, "WARNING: handleGCPfrom (): %s:
%s\n",
> +                 filename, "fopen () failed");
> +        return -1;
> +    }
> +
> +    /* parse the file */
> +    /* NB: for better performance, CPLRealloc () the
array in bigger
> +     *     steps */
> +    for (lineno = 0, new_points = 0; ! feof (fp);
lineno++) {
> +        int rv;
> +        float pix, lin, x, y, elev;
> +
> +        /* NB: fscanf () is hardly a good idea */
> +        {
> +            ssize_t read;
> +            if ((read = getline (&linebuf, &linesz, fp))
< 0) {
> +                /* NB: a warning if not EOF here? */
> +                break;
> +            }
> +        }
> +
> +        rv = sscanf (linebuf, " %f %f %f %f %f",
> +                     &pix, &lin, &x, &y, &elev);
> +        if (rv < 4) {
> +            fprintf (stderr,
> +                     ("WARNING: handleGCPfrom (): %s:%d"
> +                      ": cannot parse line\n"),
> +                     filename, lineno);
> +            continue;
> +        }
> +
> +        /* append the GCP just read to the array */
> +
> +        new_points++;
> +        *gcpp = (GDAL_GCP *)
> +            CPLRealloc (*gcpp, sizeof (**gcpp) *
(++(*ngcpp)));
> +        GDAL_GCP *tailp = *gcpp + *ngcpp - 1;
> +        GDALInitGCPs (1, tailp);
> +
> +        tailp->dfGCPPixel = pix;
> +        tailp->dfGCPLine = lin;
> +        tailp->dfGCPX = x;
> +        tailp->dfGCPY = y;
> +    }
> +
> +    /* deallocate the line buffer */
> +    CPLFree (linebuf);
> +
> +    /* close the file */
> +    fclose (fp);
> +
> +    /* . */
> +    return new_points;
> +}
> +
>
+/**********************************************************
**************/
>  /*                             ProxyMain()
*/
>
/***********************************************************
*************/
>
> @@ -221,6 +295,11 @@
>              /* should set id and info? */
>          }
>
> +        else if (EQUAL (argv[i], "-gcp_from") && i <
argc - 1) {
> +            handleGCPfrom (argv[++i], &pasGCPs,
&nGCPCount);
> +            ++i;
> +        }
> +
>          else if( EQUAL(argv[i],"-a_nodata") && i < argc -
1 )
>          {
>              bSetNoData = TRUE;
>
> [1] http://trac.osgeo.org/gdal/ticket/2079
> [2] http://www.gnu.org/software/libc/
> [3] http://www.gnu.org/software/gnulib/
>
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