[AstroPy] How can I preserve the precision of the data in the votable file?

Michael Droettboom mdroe@stsci....
Thu Mar 7 10:12:11 CST 2013


By default, floating point values are output using 4 decimal points of 
precision.  You can control the amount of precision using the 
"precision" attribute on the field. This is either "F" followed by a 
number of decimal places, or "E" followed by the number of significant 
digits.  For example, when you define your fields, you can do:

# Define some fields
table.fields.extend([
         Field(votable,  name="float",  datatype="double",  precision="E8"))

See also:

http://www.ivoa.net/Documents/VOTable/20040811/REC-VOTable-1.1-20040811.html#ToC26

Mike

On 03/07/2013 06:33 AM, Susana Sanchez Exposito wrote:
> Hello again,
>
> I have followed the instructions given by Tom Aldcroft as answer of my
> previous mail (thanks for that!), and finally I get the xml file with
> the VOTable, but I realized the number are rounded when they are
> written in the xml file.
>
> For example, if I have a table like this:
> (I built this Table following the example in
> https://astropy.readthedocs.org/en/v0.2/io/votable/index.html,
> "Building a new table from scratch"):
>
> In [62]: table
> Out[62]: <astropy.io.votable.tree.Table object at 0x32bcbd0>
>
> In [63]: table.array
> Out[63]:
> masked_rec.array(data = [(17.257360147629999, 18.999976544568401)
>   (13.257360147629999, 78.999976544568398)],
>                   mask = [(False, False) (False, False)],
>             fill_value = (1e+20, 1e+20),
>                  dtype = [('precision', '<f8'), ('precision2', '<f8')])
>
>
> When I build the xml file with the comand votable.to_xml, the file
> contains this data:
>
>   <TABLEDATA>
>       <TR>
>        <TD>17.2574</TD>
>        <TD>19</TD>
>       </TR>
>       <TR>
>        <TD>13.2574</TD>
>        <TD>79</TD>
>       </TR>
>      </TABLEDATA>
>
>
> As you can see, the numbers have been rounded, but I would like to
> preserve the precision of these data. Is this possible?
>
>
> Thanks again for your useful help!
>
> Susana.

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