Opened 14 years ago

Closed 7 years ago

#1742 closed enhancement (wontfix)

[PATCH] Enhancement. Add metadata for PNG, GIF and JPG

Reported by: Even Rouault Owned by: warmerdam
Priority: normal Milestone:
Component: GDAL_Raster Version: svn-trunk
Severity: normal Keywords:


This patch adds the following features :

  • for BMP, PNG, GIF and JPG, read projection ref from a .prj (adds a ReadProjectionRefFromFile? in GDALDataset class)
  • for PNG, GIF and JPEG, supports read and write of geo transform, projection ref and datasets metadata in the image file itself (using tEXT for PNG, APPLICATION_EXT_FUNC_CODE extension for GIF89a and a custom marker section for JPG)

(It's a bit intersection on previous patches from mine, #1734 and #1467)

Attachments (1)

gdal_svn_gifjpgbmppng.patch (44.6 KB) - added by Even Rouault 14 years ago.

Download all attachments as: .zip

Change History (7)

Changed 14 years ago by Even Rouault

Attachment: gdal_svn_gifjpgbmppng.patch added

comment:1 Changed 14 years ago by Even Rouault

Component: defaultGDAL_Raster
Version: unspecifiedsvn-trunk

comment:2 Changed 14 years ago by Even Rouault

Type: defectenhancement

comment:3 Changed 14 years ago by warmerdam


I'm iffy on this patch because it seems to duplicate some of what is accomplished by the PAM mechanism (persistent auxilary metadata in an .aux.xml file). It also doesn't fallback to letting the PAM mechanism operate if no metadata is found in the file itself so it can't be applied as is.

The goal here is to introduce a gdal specific metadata storage format for each of these formats - is that right?

I'd like to hold this for future consideration.

comment:4 Changed 14 years ago by Even Rouault

I wasn't aware of the PAM mechanism...

Yes, the goal was to introduce a gdal specific metadata storage format for each of these formats. The idea is that people have a tendency to forget auxiliary files and just copy/paste the main interest file. So, when the format allows to store metadata in it, it could be interesting to do it.

But I agree with you this may be a kind of "gadget" and not enough scalable. At least, the patch should allow fallback to the PAM mechanism.

comment:5 Changed 7 years ago by Jukka Rahkonen

Because of the PAM mechanism and additions made to PNG, GIF and JPG drivers to handle more metadata, is there still need for this ticket?

comment:6 Changed 7 years ago by Even Rouault

Resolution: wontfix
Status: newclosed

For the above mentionned reasons, this patch isn't really appropriate for general interest.

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