Re: [gdal-dev] ogr2ogr changes field length
Hi Jukka, GDAL has the internal default of 80 characters. GDAL users do not really need other options because fields are automatically expanded when longer strings are appended afterwards but if the shapefile is used in some other software it does happen that it is impossible to insert long strings because there is no room for that in the table. I suppose that you also know that by using the field width of 254 you are also maximizing the size of the .dbf file because it reserves the same fixed amount of disk space for each cell. got it! Yes, I'm aware of the disk space :) Cheers and thanks Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
Hi, GDAL has the internal default of 80 characters. GDAL users do not really need other options because fields are automatically expanded when longer strings are appended afterwards but if the shapefile is used in some other software it does happen that it is impossible to insert long strings because there is no room for that in the table. I suppose that you also know that by using the field width of 254 you are also maximizing the size of the .dbf file because it reserves the same fixed amount of disk space for each cell. -Jukka Rahkonen- -Alkuperäinen viesti- Lähettäjä: matteo Lähetetty: perjantai 8. lokakuuta 2021 12.29 Vastaanottaja: Rahkonen Jukka (MML) ; Even Rouault ; gdal-dev@lists.osgeo.org Aihe: Re: [gdal-dev] ogr2ogr changes field length Hi Jukka, works perfectly, thanks! so no default options to impose the field length but it is alterable after Cheers! Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
Hi Jukka, works perfectly, thanks! so no default options to impose the field length but it is alterable after Cheers! Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
Hi,
The best I can suggest to do by using just GDAL utilities is to run this kind
of ogrinfo command for each text field that you have in the shapefile schema:
ogrinfo my_shape.shp -sql "alter table my_shape alter column STRING_1 TYPE
character(254)"
(right, the max length is 254).
-Jukka Rahkonen-
-Alkuperäinen viesti-
Lähettäjä: matteo
Lähetetty: perjantai 8. lokakuuta 2021 11.20
Vastaanottaja: Rahkonen Jukka (MML) ; Even
Rouault ; gdal-dev@lists.osgeo.org
Aihe: Re: [gdal-dev] ogr2ogr changes field length
Hi Jukka,
> The strings fields are created by default with width 80. If there are longer
> strings in the data the width is automatically extended up till 255
> characters that is the maximum that dBase format supports. If strings are
> shorter than 80 charaters it is possible to use RESIZE and shrink the width
> to match the longest string used in that field.
>
> If you need better control on field widths I suppose you must create an empty
> shapefile for ogr2ogr to append by your own code.
>
> # Add a new field.
> field_defn = ogr.FieldDefn('NEWFLD', ogr.OFTString)
> field_defn.SetWidth(12)
>
> Do you have some concrete problem with field widths that you want to resolve?
I'm "dumping" empty tables of a schema to shapefile and actually yes, I need
that the fields with unlimited text set up in PG should be the maximum (so 254)
in the final shapefiles.
All the tables are empty so I guess this is the "problem" I have
Cheers and thanks
Matteo
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Re: [gdal-dev] ogr2ogr changes field length
Hi Jukka,
The strings fields are created by default with width 80. If there are longer
strings in the data the width is automatically extended up till 255 characters
that is the maximum that dBase format supports. If strings are shorter than 80
charaters it is possible to use RESIZE and shrink the width to match the
longest string used in that field.
If you need better control on field widths I suppose you must create an empty
shapefile for ogr2ogr to append by your own code.
# Add a new field.
field_defn = ogr.FieldDefn('NEWFLD', ogr.OFTString)
field_defn.SetWidth(12)
Do you have some concrete problem with field widths that you want to resolve?
I'm "dumping" empty tables of a schema to shapefile and actually yes, I
need that the fields with unlimited text set up in PG should be the
maximum (so 254) in the final shapefiles.
All the tables are empty so I guess this is the "problem" I have
Cheers and thanks
Matteo
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Re: [gdal-dev] ogr2ogr changes field length
Hi,
The strings fields are created by default with width 80. If there are longer
strings in the data the width is automatically extended up till 255 characters
that is the maximum that dBase format supports. If strings are shorter than 80
charaters it is possible to use RESIZE and shrink the width to match the
longest string used in that field.
If you need better control on field widths I suppose you must create an empty
shapefile for ogr2ogr to append by your own code.
# Add a new field.
field_defn = ogr.FieldDefn('NEWFLD', ogr.OFTString)
field_defn.SetWidth(12)
Do you have some concrete problem with field widths that you want to resolve?
-Jukka Rahkonen-
-Alkuperäinen viesti-
Lähettäjä: gdal-dev Puolesta matteo
Lähetetty: perjantai 8. lokakuuta 2021 9.11
Vastaanottaja: Even Rouault ;
gdal-dev@lists.osgeo.org
Aihe: Re: [gdal-dev] ogr2ogr changes field length
Hi Even,
> If you add -lco RESIZE=YES fields will be resized to their minimum size.
> See
> https://gdal.org/drivers/vector/shapefile.html#layer-creation-options
yep I see. I also read
* String fields without an assigned width are treated as 80 characters
does it mean that if a field is set as TEXT in PG (without length
definition) the conversion to shapefile is automatically set to 80 and what we
can do is to resize the field length only to have less characters?
Cheers!
Matteo
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Re: [gdal-dev] ogr2ogr changes field length
Hi Even, If you add -lco RESIZE=YES fields will be resized to their minimum size. See https://gdal.org/drivers/vector/shapefile.html#layer-creation-options yep I see. I also read * String fields without an assigned width are treated as 80 characters does it mean that if a field is set as TEXT in PG (without length definition) the conversion to shapefile is automatically set to 80 and what we can do is to resize the field length only to have less characters? Cheers! Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
If you add -lco RESIZE=YES fields will be resized to their minimum size. See https://gdal.org/drivers/vector/shapefile.html#layer-creation-options Le 07/10/2021 à 17:40, matteo a écrit : Even, still a weird issue with the command. I'm using this command ogr2ogr -f "ESRI Shapefile" /home/matteo/myfolder "PG:dbname='mydb' host=myhost port=5432 user='myuser' password='mypws' sslmode=disable schemas='dati'" --config PG_USE_COPY YES --config PG_LIST_ALL_TABLES YES -progress' so without any append or overwrite (dumping a whole schema in a folder). I've both spatial and not spatial tables and for all of them the text fields are created in PG like: CREATE TABLE mytable ( ID SERIAL PRIMARY KEY, . NOTE text ) and all these fields are 80 characters long in the newly created shapefiles... I don't know if I can give some more information.. Cheers and thanks Matteo -- http://www.spatialys.com My software is free, but my time generally not. ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
Even, still a weird issue with the command. I'm using this command ogr2ogr -f "ESRI Shapefile" /home/matteo/myfolder "PG:dbname='mydb' host=myhost port=5432 user='myuser' password='mypws' sslmode=disable schemas='dati'" --config PG_USE_COPY YES --config PG_LIST_ALL_TABLES YES -progress' so without any append or overwrite (dumping a whole schema in a folder). I've both spatial and not spatial tables and for all of them the text fields are created in PG like: CREATE TABLE mytable ( ID SERIAL PRIMARY KEY, . NOTE text ) and all these fields are 80 characters long in the newly created shapefiles... I don't know if I can give some more information.. Cheers and thanks Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
Hi Even, thanks for the hint :) it si just an additional step Cheers! Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] ogr2ogr changes field length
Matteo, When overwriting, a fresh new file/table is creating, without keeping anything from the existing version. You could probably just blank your target with ogrinfo target.shp -sql "DELETE FROM target" -dialect SQLITE and then ogr2ogr -append target.shp PG: -nln target Even Le 06/10/2021 à 17:37, matteo a écrit : Hi list, I've a script that uses ogr2ogr to copy, actually overwrite, tables from PG to shapfiles. The PG fields are all text (without a specified length) and the target shapefile that will be overwritten have all text field length equals to 254. When overwriting the length is changes to 80. Is there any specific option to keep the original field length? Cheers and thanks Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev -- http://www.spatialys.com My software is free, but my time generally not. ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] ogr2ogr changes field length
Hi list, I've a script that uses ogr2ogr to copy, actually overwrite, tables from PG to shapfiles. The PG fields are all text (without a specified length) and the target shapefile that will be overwritten have all text field length equals to 254. When overwriting the length is changes to 80. Is there any specific option to keep the original field length? Cheers and thanks Matteo ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
