[gdal-dev] vector NODATA for Z values?

Fri Jan 26 03:17:01 PST 2024

Hi,

IMHO, I would not complicate the driver for that. Such options would 
actually be quite generic, and if we wanted to implement them, they 
would probably better be implemented as options of ogr2ogr (but should 
be done separately from your driver submission)

Even

Le 26/01/2024 à 10:59, Abel Pau via gdal-dev a écrit :
>
> Hi again,
>
> I understand...
>
> Perhaps an option could be using something like *-lco 
> Z_NODATA_VALUE_DST="X"* to translate NODATA  from origin to this value 
> X (NaN, 0, or whatever it may be). The driver can offer this number 
> instead of the own NODATA and the user can know that the X value in 
> destination will mean NODATA.
>
> On the other hand, a user could also specify *-lco 
> Z_NODATA_VALUE_SRC="Y"* so that a driver can identify a value 
> considered NODATA in the source and translate it to the own NODATA 
> value (or the one specified by the first parameter (if it exists)).
>
> Is this too complicated? Are there any repercussions that I'm not seeing?
>
> Thanks.
>
> *De:*Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi>
> *Enviado el:* dijous, 25 de gener de 2024 18:27
> *Para:* Abel Pau <a.pau at creaf.uab.cat>; gdal-dev at lists.osgeo.org
> *Asunto:* Re: vector NODATA for Z values?
>
> Hi,
>
> I think that it depends on the file format. Rather often it is set to 
> zero but I have seen NaN in many places. However, shapefiles 
> explicitly denies NaN
>
> “…Positive infinity, negative infinity, and Not-a-Number (NaN) values 
> are not allowed in shapefiles. Nevertheless, shapefiles support the 
> concept of "no data" values, but they are currently used only for 
> measures. Any floating point number smaller than –1038 is considered 
> by a shapefile reader to represent a "no data" value.
>
> With the SQLite dialect it is possible to select the value but NaN is 
> not accepted.
> Can be tested with
> ogrinfo -dialect SQLite -sql "select CastToXYZ(ST_GeomFromText('POINT 
> (1 2)'),3)" point.json
>
> -Jukka Rahkonen-
>
> *Lähettäjä:*gdal-dev <gdal-dev-bounces at lists.osgeo.org> *Puolesta 
> *Abel Pau via gdal-dev
> *Lähetetty:* torstai 25. tammikuuta 2024 19.07
> *Vastaanottaja:* gdal-dev at lists.osgeo.org
> *Aihe:* [gdal-dev] vector NODATA for Z values?
>
> Hi,
>
> there is any value in GDAL for VECTORS that indicates that a concrete 
> value of a Z is not known (z nodata value)?
>
> I couldn’t find it anywhere.
>
> In MiraMon format we use one concrete number documented in our format 
> pdf (-1.0E+300) an in the driver it’s planned to translate it to the 
> same number. I could translate it to the one I am asking. And the same 
> for detecting nodata Z and translate them to -1.0E+300 when reading 
> another format.
>
> Thanks!
>
> *Abel Pau Garcia*
>
> *GIS developer*
>
> 	
>
> https://www.creaf.cat/sites/default/files/creaf-signature.png
>
> *a.pau at creaf.uab.cat* <mailto:a.pau at creaf.uab.cat>
>
> *Let's chat on Teams!* 
> <https://teams.microsoft.com/l/chat/0/0?users=a.pau@creaf.uab.cat>
>
> *Tel. +34 934814277*
>
> 	
>
> https://www.creaf.cat/sites/default/files/so-en-signature.png
>
> https://www.creaf.cat/sites/default/files/twitter-icon-signature.png 
> <https://twitter.com/CREAF_ecologia>https://www.creaf.cat/sites/default/files/linkedin-icon-signature.png 
> <https://www.linkedin.com/company/1363052?trk=tyah&trkInfo=clickedVertical:company,clickedEntityId:1363052,idx:2-1-2,tarId:1465807877789,tas:creaf>https://www.creaf.cat/sites/default/files/youtube-icon-signature.png 
> <https://www.youtube.com/c/creafecologia>https://www.creaf.cat/sites/default/files/instagram-icon-signature.png 
> <https://www.instagram.com/CREAF_ecologia/>
>
> *www.creaf.cat* <http://www.creaf.cat/>*| **http://blog.creaf.cat* 
> <http://blog.creaf.cat/>
>
> 	
>
> https://www.creaf.cat/sites/default/files/uab_logo_signatura.png
>
> CREAF. Campus UAB. Edifici C. 08193 Bellaterra (Barcelona)
>
>
> Before printing this electronic message, think about the environment.
>
> http://www.creaf.uab.cat/_signatura/line.gif
>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/gdal-dev

-- 
http://www.spatialys.com
My software is free, but my time generally not.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 3657 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0006.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.png
Type: image/png
Size: 2547 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0007.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.png
Type: image/png
Size: 505 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0008.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image004.png
Type: image/png
Size: 446 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0009.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image005.png
Type: image/png
Size: 553 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0010.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image006.png
Type: image/png
Size: 582 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0011.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image007.jpg
Type: image/jpeg
Size: 2208 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0002.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image008.jpg
Type: image/jpeg
Size: 1111 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20240126/d62a622c/attachment-0003.jpg>