Hi Martin, I am not all that familiar with ISO 19123 but I do think that we need to accommodate ISO terminology in SIS. I am completely open to anything that you come up with...In other words, use your best judgement.
Thanks! Adam On Fri, Feb 15, 2013 at 9:47 AM, Martin Desruisseaux < [email protected]> wrote: > Hello all > > A set of range-related classes (Range, NumericRange, MeasurementRange, > RangeFormat, and RangeSet to arrive soon) have been committed. One purpose > of those classes is to specify the values where data are available, > typically as elevation (/z/) values or time (/t/) values. Many applications > or file formats use single values for /z/ and /t/. For example NetCDF files > typically specify the /z/ values of data slices in a "height" or "depth" > vector, and /t/ values in a "time" vector. However I suggest to always work > with ranges (or intervals) in Apache SIS mechanic. For example instead of > specifying a single /t/ instant for any kind of data, we would always > specify a [/start time/ ... /end time/] range (even if the range is very > short in time, there is no instantaneous measurement). The rational are: > > * Consistency with the (/x/,/y/) dimensions: when specifying a > bounding box, we implicitly specify range of values for the /x/ and > /y/ dimensions. We are better to treat every dimensions in the same way. > * Avoid tricky questions like "how far is it reasonable to > interpolate?". If time were specified only as single /t/ values and > if the user asks for data 3 days after the nearest time, how to know > if it is reasonable to interpolate? If the data have a "/start > time/" and "/end time/" instead, the question can be solved much > more easily. This topic had been raised in a previous > "Meteo-oceanography" meeting at OGC. > > > Of course, user interfaces are free to replace ranges by single values in > their widgets if they wish. > > However we have a minor name clash. This Range class were designed in old > days before ISO 19123. Now, we have the ISO 19123 standard for Coverage > features (which include rasters). If we consider a Coverage as a kind of > function, then according ISO 19123 terminology the "/domain/" is the set of > valid inputs (typically geodetic coordinates, but not necessarily) and the > "/range/" is the set of valid outputs. So we have a risk of function > between the Range class defined as a [/minimum/ ... /maximum/] tupple in > the sis-utility module, and the "/range/" concept defined in ISO 19123 as > the set of possible output values of a coverage (e.g. the set of pixel > values in a raster). > > So we have a choice: > > * Keep the current Range name on the assumption that calling a > [/minimum/ ... /maximum/] tupple a "range" is common enough to avoid > confusion; > * Rename Range into something else, for example Interval, in order to > make Apache SIS fit better with ISO terminology (in this case, > avoiding a name clash between two closely related concepts). > > Any opinion? > > Martin > >
