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Fix the case of wongs coordenates shiped by NASA in the MODIS L3 files. #8935

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Merged
joa-quim merged 2 commits into from
Mar 19, 2026
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Fix the case of wongs coordenates shiped by NASA in the MODIS L3 files. #8935

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8930410
Add a patch to fix the errors in coordinates of the NASA MODIS L3 files
joa-quim Mar 19, 2026
4ad0c4a
Fix the tests if coords can be global geogs
joa-quim Mar 19, 2026
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16 changes: 16 additions & 0 deletions src/gmt_nc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -913,6 +913,22 @@ GMT_LOCAL int gmtnc_grd_info (struct GMT_CTRL *GMT, struct GMT_GRID_HEADER *head

gmt_M_free (GMT, xy); /* Done with the array */

/* This bit is a hack to deal with extremly annoying fact that NASA MODIS grids keep having wrong coordinates.
The difference are minute, probably originated from a flot64/float32 roundoff shit, but the fact is that their
coordinates are wrong and the difference overflows the [-90 90] lat interval and as a consequece projections
breake because they fail sanity checks. See issue https://github.com/GenericMappingTools/gmt/issues/8930
*/
if ((fabs(header->wesn[YHI] - header->wesn[YLO] - 180) < header->inc[GMT_Y] * 1e-2) &&
(fabs(header->wesn[XHI] - header->wesn[XLO] - 360) < header->inc[GMT_X] * 1e-2) &&
(fabs(header->wesn[YHI] - 90.0) < header->inc[GMT_Y] * 1e-4 || fabs(90.0 - header->wesn[YLO]) < header->inc[GMT_Y] * 1e-4)) {
header->wesn[YLO] = -90.0, header->wesn[YHI] = 90.0;
/* If any case of this happens to not fall into the [-180 180] or [0 360] range, the shit in longituds will remain. */
if (rint(header->wesn[XLO]) == -180.0) {header->wesn[XLO] = -180.0; header->wesn[XHI] = 180.0;}
if (rint(header->wesn[XHI]) == 0.0) {header->wesn[XLO] = 0.0; header->wesn[XHI] = 360.0;}
header->inc[GMT_Y] = (header->wesn[YHI] - header->wesn[YLO]) / (header->n_rows - !header->registration);
header->inc[GMT_X] = (header->wesn[XHI] - header->wesn[XLO]) / (header->n_columns - !header->registration);
}

/* Get information about z variable */
gmtnc_get_units (GMT, ncid, z_id, header->z_units);
if (nc_get_att_double (ncid, z_id, "scale_factor", &header->z_scale_factor)) header->z_scale_factor = 1.0;
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