Unit issues in ISO-MME 2.0
Posted: Wed Jul 14, 2010 9:51 am
As we want to use the ISO-MME 2.0 in the future I mentioned some issues with the physical units which make it quite inconvenient to work with this new "standard".
Issues
1. For the same physical dimension there should be used the same unit in all data and information files.
I found same different units, e.g. [rad] and [°] or [m] and [mm] or [s] and [µs]. ISO-MME 1.x does not seem to have this unit mix.
2. The unit should be the same as in the old (1.x) ISO-MME, e.g. tempreature was [°K] in ISO-MME 1.x and is now [°C] which is quite nice to read for Europeans but may be not for everybody in the world. Another example is the 'shutter time' in the movie information file which was [s] and is now [µs]
Solutions:
1. Only SI-units are allowed to use as it seems to be in the ISO-MME 1.x.
2. If some units are different from the SI-units because this unit will give better readable values, e.g. angle [°] instead of [rad] for everyone in the world, this could be mentioned in the TS-document.
3. Therefore a list of dimensions and used units can or should be added to the TS-document,
e.g. time = [s], displacement = [m], temperature = [°K] , angle = [°] ...
In this case the unit column can be removed from the data and info file description or can be replaced by a remark like
'use unit for time', 'use unit for temperature', ...
Pros
Hopefully this will help people to make less faults using the ISO-MME 2.0 and makes it easier to convert data from 1.x to 2.0.
Cons
Even this could result in some less good readable values within the info and data files the presentation of the values normally is done by some software, which should be able to convert the units to better readable values even if this feature seems to be quite new for some commonly used software products.
Issues
1. For the same physical dimension there should be used the same unit in all data and information files.
I found same different units, e.g. [rad] and [°] or [m] and [mm] or [s] and [µs]. ISO-MME 1.x does not seem to have this unit mix.
2. The unit should be the same as in the old (1.x) ISO-MME, e.g. tempreature was [°K] in ISO-MME 1.x and is now [°C] which is quite nice to read for Europeans but may be not for everybody in the world. Another example is the 'shutter time' in the movie information file which was [s] and is now [µs]
Solutions:
1. Only SI-units are allowed to use as it seems to be in the ISO-MME 1.x.
2. If some units are different from the SI-units because this unit will give better readable values, e.g. angle [°] instead of [rad] for everyone in the world, this could be mentioned in the TS-document.
3. Therefore a list of dimensions and used units can or should be added to the TS-document,
e.g. time = [s], displacement = [m], temperature = [°K] , angle = [°] ...
In this case the unit column can be removed from the data and info file description or can be replaced by a remark like
'use unit for time', 'use unit for temperature', ...
Pros
Hopefully this will help people to make less faults using the ISO-MME 2.0 and makes it easier to convert data from 1.x to 2.0.
Cons
Even this could result in some less good readable values within the info and data files the presentation of the values normally is done by some software, which should be able to convert the units to better readable values even if this feature seems to be quite new for some commonly used software products.