L0 resolutions with repeating decimals

Background

• MERIT DEM is at 3 arc seconds i.e. 0 deg 0 min 3 secs OR 0.00083333.....33333…..
• I use ASCII input format. All of input .asc files and header.txt have the L0 resolution in decimal degrees.

Issue

• I noticed that in order to avoid truncation errors the user needs to enter a lot of decimal places in the .asc files and header.txt. E.g. 18 decimal places were not enough. So I entered 100 decimal places - worked. (note: the error occurs at lines 546-547 of mo_grid.f90, calculation of xllcorner and yllcorner from L0 and L2 resolutions)

Solution (?)

• In mHM we have two coordinate systems - metric and lat lon. The latter has numeral format of decimal degrees. However, data which come as deg-min-sec when converted to decimal degrees could bear “repeating decimals” leading to truncation errors as in case of MERIT DEM resolution.
• Wouldn’t it be better if users had the option to enter the resolution in deg-min-sec or decimal degrees as deemed fit? That would be more elegant/ intuitive than entering a lot of decimal places.
• I don’t have experience in using .nc files for L0 data (except lai.nc). Does that solve this issue already?