fitsfile* create_fits_file(const char* filename, int precision,
int width, int height, int num_times, int num_channels,
double centre_deg[2], double fov_deg[2], double start_time_mjd,
double delta_time_sec, double start_freq_hz, double delta_freq_hz,
int* status)
{
long naxes[4];
double delta;
fitsfile* f = 0;
FILE* t = 0;
if (*status) return 0;
/* Create a new FITS file and write the image headers. */
t = fopen(filename, "rb");
if (t)
{
fclose(t);
remove(filename);
}
naxes[0] = width;
naxes[1] = height;
naxes[2] = num_channels;
naxes[3] = num_times;
fits_create_file(&f, filename, status);
fits_create_img(f, (precision == OSKAR_DOUBLE ? DOUBLE_IMG : FLOAT_IMG),
4, naxes, status);
fits_write_date(f, status);
/* Write axis headers. */
delta = oskar_convert_fov_to_cellsize(fov_deg[0] * M_PI/180, width) * 180/M_PI;
write_axis_header(f, 1, "RA---SIN", "Right Ascension",
centre_deg[0], -delta, width / 2 + 1, 0.0, status);
delta = oskar_convert_fov_to_cellsize(fov_deg[1] * M_PI/180, height) * 180/M_PI;
write_axis_header(f, 2, "DEC--SIN", "Declination",
centre_deg[1], delta, height / 2 + 1, 0.0, status);
write_axis_header(f, 3, "FREQ", "Frequency",
start_freq_hz, delta_freq_hz, 1.0, 0.0, status);
write_axis_header(f, 4, "UTC", "Time",
start_time_mjd, delta_time_sec, 1.0, 0.0, status);
/* Write other headers. */
fits_write_key_str(f, "BUNIT", "JY/BEAM", "Brightness units", status);
fits_write_key_str(f, "TIMESYS", "UTC", NULL, status);
fits_write_key_str(f, "TIMEUNIT", "s", "Time axis units", status);
fits_write_key_dbl(f, "MJD-OBS", start_time_mjd, 10, "Start time", status);
fits_write_key_dbl(f, "OBSRA", centre_deg[0], 10, "RA", status);
fits_write_key_dbl(f, "OBSDEC", centre_deg[1], 10, "DEC", status);
/*fits_flush_file(f, status);*/
return f;
}
void oskar_imager_set_fov(oskar_Imager* h, double fov_deg)
{
h->set_cellsize = 0;
h->set_fov = 1;
h->fov_deg = fov_deg;
h->cellsize_rad = oskar_convert_fov_to_cellsize(
h->fov_deg * (M_PI / 180.0), h->image_size);
}
void oskar_imager_set_size(oskar_Imager* h, int size, int* status)
{
if (size < 2 || size % 2 != 0)
{
*status = OSKAR_ERR_INVALID_ARGUMENT;
return;
}
h->image_size = size;
h->grid_size = 0;
oskar_imager_reset_cache(h, status);
(void) oskar_imager_plane_size(h);
if (h->set_fov)
h->cellsize_rad = oskar_convert_fov_to_cellsize(
h->fov_deg * (M_PI / 180.0), h->image_size);
else if (h->set_cellsize)
h->fov_deg = oskar_convert_cellsize_to_fov(
h->cellsize_rad, h->image_size) * (180.0 / M_PI);
}
static fitsfile* create_fits_file(const char* filename, int precision,
int width, int height, int num_times, int num_channels,
double centre_deg[2], double fov_deg[2], double start_time_mjd,
double delta_time_sec, double start_freq_hz, double delta_freq_hz,
int horizon_mode, const char* settings_log, size_t settings_log_length,
int* status)
{
int imagetype;
long naxes[4], naxes_dummy[4] = {1l, 1l, 1l, 1l};
double delta;
const double deg2rad = M_PI / 180.0;
const double rad2deg = 180.0 / M_PI;
fitsfile* f = 0;
const char* line;
size_t length;
if (*status) return 0;
/* Create a new FITS file and write the image headers. */
if (oskar_file_exists(filename)) remove(filename);
imagetype = (precision == OSKAR_DOUBLE ? DOUBLE_IMG : FLOAT_IMG);
naxes[0] = width;
naxes[1] = height;
naxes[2] = num_channels;
naxes[3] = num_times;
fits_create_file(&f, filename, status);
fits_create_img(f, imagetype, 4, naxes_dummy, status);
fits_write_date(f, status);
fits_write_key_str(f, "TELESCOP", "OSKAR " OSKAR_VERSION_STR, 0, status);
/* Write axis headers. */
if (horizon_mode)
{
delta = oskar_convert_fov_to_cellsize(M_PI, width);
write_axis(f, 1, "-----SIN", "Azimuthal angle",
0.0, -delta * rad2deg, (width + 1) / 2.0, status);
delta = oskar_convert_fov_to_cellsize(M_PI, height);
write_axis(f, 2, "-----SIN", "Elevation",
90.0, delta * rad2deg, (height + 1) / 2.0, status);
}
else
{
delta = oskar_convert_fov_to_cellsize(fov_deg[0] * deg2rad, width);
write_axis(f, 1, "RA---SIN", "Right Ascension",
centre_deg[0], -delta * rad2deg, (width + 1) / 2.0, status);
delta = oskar_convert_fov_to_cellsize(fov_deg[1] * deg2rad, height);
write_axis(f, 2, "DEC--SIN", "Declination",
centre_deg[1], delta * rad2deg, (height + 1) / 2.0, status);
}
write_axis(f, 3, "FREQ", "Frequency",
start_freq_hz, delta_freq_hz, 1.0, status);
write_axis(f, 4, "UTC", "Time",
start_time_mjd * 86400.0, delta_time_sec, 1.0, status);
/* Write other headers. */
fits_write_key_str(f, "TIMESYS", "UTC", NULL, status);
fits_write_key_str(f, "TIMEUNIT", "s", "Time axis units", status);
fits_write_key_dbl(f, "MJD-OBS", start_time_mjd, 10, "Start time", status);
if (!horizon_mode)
{
fits_write_key_dbl(f, "OBSRA", centre_deg[0], 10, "RA", status);
fits_write_key_dbl(f, "OBSDEC", centre_deg[1], 10, "DEC", status);
}
/* Write the settings log up to this point as HISTORY comments. */
line = settings_log;
length = settings_log_length;
for (; settings_log_length > 0;)
{
const char* eol;
fits_write_history(f, line, status);
eol = (const char*) memchr(line, '\0', length);
if (!eol) break;
eol += 1;
length -= (eol - line);
line = eol;
}
/* Update header keywords with the correct axis lengths.
* Needs to be done here because CFITSIO doesn't let us write only the
* file header with the correct axis lengths to start with. This trick
* allows us to create a small dummy image block to write only the headers,
* and not waste effort moving a huge block of zeros within the file. */
fits_update_key_lng(f, "NAXIS1", naxes[0], 0, status);
fits_update_key_lng(f, "NAXIS2", naxes[1], 0, status);
fits_update_key_lng(f, "NAXIS3", naxes[2], 0, status);
fits_update_key_lng(f, "NAXIS4", naxes[3], 0, status);
return f;
}
