rounding errors in world coordinates of exported polyline region as ds9 format

[kswang1029]

if a polyline is exported as casa format in world coordinate, we see

#CRTFv0 CASA Region Text Format version 0
polyline [[17:56:21.67061, -021.57.16.6090], [17:56:21.69974, -021.57.21.6747], [17:56:21.56575, -021.57.19.4053], [17:56:21.57449, -021.57.23.8226], [17:56:21.48419, -021.57.22.9715], [17:56:21.49001, -021.57.25.6867]] coord=J2000, corr=[I], linewidth=2, linestyle=-, symsize=1, symthick=1, color=2ee6d6, font=Helvetica, fontsize=10, fontstyle=bold, usetex=false

However, if the format is ds9 we see

#Region file format: DS9 CARTA 3.0.0-beta.1b
global color=green dashlist=8 3 width=1 font="helvetica 10 normal roman" select=1 highlite=1 dash=0 fixed=0 edit=1 move=1 delete=1 include=1 source=1
fk5
polyline(269.0903, -21.9546, 269.0904, -21.9560, 269.0899, -21.9554, 269.0899, -21.9566, 269.0895, -21.9564, 269.0895, -21.9571) # color=#2EE6D6 width=2

As this is in degree, we will need more digits to prevent rounding errors.

[pford]

This is likely an issue with other DS9 regions as well, such as polygon.