Opened 5 months ago

Closed 5 months ago

Last modified 5 months ago

#6859 closed defect (fixed)

DTED driver creates incorrect files on latitudes -80, -75, -70 and -50

Reported by: pnicolas Owned by: warmerdam
Priority: normal Milestone: 2.1.4
Component: default Version: unspecified
Severity: normal Keywords:
Cc:

Description

When creating a dted file, pixel width depends on latitude. Values are briefly described on https://en.wikipedia.org/wiki/DTED or in the full specification at http://earth-info.nga.mil/publications/specs/printed/89020A/89020A_DTED.pdf

Tiles are referenced by the lower left corner, a tile with lower left corner at 50S latitude covers 50S to 49S. The specification is not explicit on the step to be used on such tiles but it should be the step for latitude 0-50.

For instance, the srtm files are distributed as dted on earthexplorer. Tile SRTM3S50W075V2 has dimensions 1201x1201. Executing gdal_translate -of dted s50_w075_3arc_v2.dt1 translated.dt1 produces a 601x1201 file.

The thresholds in dted_create.c should be on the lower left for northern hemisphere and upper left for southern hemisphere on https://trac.osgeo.org/gdal/browser/trunk/gdal/frmts/dted/dted_create.c#L147

Attachments (1)

dted_step.patch (2.4 KB) - added by pnicolas 5 months ago.

Download all attachments as: .zip

Change History (6)

comment:1 Changed 5 months ago by Even Rouault

If you've a patch to fix this, this would be welcome

Changed 5 months ago by pnicolas

Attachment: dted_step.patch added

comment:2 Changed 5 months ago by Even Rouault

Resolution: fixed
Status: newclosed

In 38002:

DTED: correctly create files at latitudes -80, -75, -70 and -50 (patch by pnicolas, fixes #6859)

comment:3 Changed 5 months ago by Even Rouault

In 38003:

DTED: correctly create files at latitudes -80, -75, -70 and -50 (patch by pnicolas, fixes #6859)

comment:4 Changed 5 months ago by Even Rouault

In 38004:

DTED: correctly create files at latitudes -80, -75, -70 and -50 (patch by pnicolas, fixes #6859)

comment:5 Changed 5 months ago by Even Rouault

Milestone: 2.1.4

Thanks !

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