[gdal-dev] OGR Field Types?

[Even Rouault]

Le jeudi 21 mai 2015 23:17:26, Stefan Keller a écrit :
> Hi Even
> 
> I just see some type mod and subtype definitions for .csvt files in
> the CSV docs [1] :
> <<
> In a single line the types for each column have to be listed with
> double quotes and be comma separated (e.g., "Integer","String"). It is
> also possible to specify explicitly the width and precision of each
> column, e.g. "Integer(5)","Real(10.7)","String(15)". The driver will
> then use these types as specified for the csv columns. Starting with
> GDAL 2.0, subtypes can be passed between parenthesis, such as
> "Integer(Boolean)", "Integer(Int16)" and "Real(Float32)"
> <<
> 
> Following questions and suggestions about .csvt:
> 1. Do type names really have to be in double quotes?
No
> 2. Is the separator always comma or can it also be a semicolon?
Yes, always comma
> 3. What about a Geometry type with subtypes? I suggest to add
> 4. "Geometry(Easting)","Geometry(Northing)"
For points only I guess? Well you can build points with a OGR VRT from 2 CSV 
columns. I might perhaps add in some time an open option to specify the 
columns for the easting/longitude and northing/latitude.
> 5. "Geometry" -- encoded in WKT; having subtype values WKT (default),
> Point, LineString, Polygon.
"WKT" is not really consistant with Point,LineString,Polygon since the later 
would be expressed as WKT I guess. So perhaps WKT, WKT(Point), 
WKT(LineString), WKT(Polygon) ?

> 
> What do you think?
> This could also make QGIS "Add Delimited Text Layer..." even better.
> 
> --S.
> 
> [1] http://www.gdal.org/drv_csv.html
> 
> 2015-04-29 22:57 GMT+02:00 Stefan Keller <sfkeller at gmail.com>:
> > Salut Even,
> > 
> > Merci!
> > 
> > 2015-04-29 20:35 GMT+02:00 Even Rouault <even.rouault at spatialys.com>:
> >> Stefan
> >> 
> >>> Questions:
> >>> 1. How is 'binary' encoded? E.g. when defining binary in a CSV file,
> >>> how is it encoded? Hex?
> >> 
> >> There's no support in the CSV driver for binary data
> >> 
> >>> 2. Can a field in a CSV input files have a IntegerList or a Binary?
> >> 
> >> No. Well on writing, the IntegerList will be serialized as a string. But
> >> not recognized as IntegerList on reading
> >> 
> >>> 3. What is the value delimiter in a field of type IntegerList,
> >>> Integer64List, RealList, StringList?
> >> 
> >> The default serializatoin will be
> >> (number_of_elements:val1,val2,...,valn), but currently it is truncated
> >> to 80 chracters
> >> 
> >>> 4. "Boolean, Int16, Float32" are mentioned as subtypes. Are there more
> >>> subtypes?
> >> 
> >> Not currently. See
> >> https://trac.osgeo.org/gdal/wiki/rfc50_ogr_field_subtype
> >> 
> >> Even
> >> 
> >> --
> >> Spatialys - Geospatial professional services
> >> http://www.spatialys.com

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com