Cheers, >> Well, grid spectra, i.e. volume data, is a new kind of data so >> adding it >> will likely be considerable amount of design work and also it will >> involve touching parts of Gwyddion code that don't like being >> touched. > > AFAIK grid spectra are taken in discrete steps - so it's much like the > allready implemented spectra for some points - but with much more > points ;) > > But take some look at the file specification when it arrives ;)
Today I sadly had no time to have a look at the Omicron Scala manual, but I'll do this tomorrow in the lab. So far as I read the specification grid data is saved as follows: The data in general is saved as unsigned 16 bit integer in network byte order (Omicron calls this "binary data" files). So the file size is 2 byte * number of datapoints * number of spectra. The files extensions are s[fb][01], where s stands for spectroscopy, f and b for forward resp. backward and 0 and 1 are the channels. The correct mapping is defined in the parameter file. The spectra are saved "frame by frame", where each frame consists of the n-th data point of all spectra. In other words: Guess I've got m spectra and p data points, then the numbers (2 byte!) 1 to m form the first data point of the spectra, m+1 to 2*m the second and so on until m*(p-1)+1 to m*p. This format is very useful if you want to obtain the averaged curve over all spectra. Back in university I could attach a simple program of mine that computes the averaged spectrum. If you want to get the spectrum of the n-th data point, you have to read the numbers n, m+n, 2m+n, ... (p-1)*m+n. I've currently not proven, where the data points start, but I guess that the origin of the coordinate systems starts at the lower left (in forward direction, backward might be the lower right) as known from the topography files. The number of spectra points per line and lines is given in the parameter files section "Measurement parameters" by the keys "Spectroscopy Points in X" and "Spectroscopy Lines in Y". So the number of spectra m is x*y. The distance of each spectroscopy point in pixels is given by "Spectroscopy Grid Value in X" and "Spectroscopy Grid Value in Y". To compute physical values from the data found in the spectroscopy files we have to inspect the "Spectroscopic Channels" in the parameter file. But this should be the same calculation as done for single point spectra. Back in university I could attach a simple grid data set, the ones I've got at home are at least 2 MB in size. Yours, -- Robb Bean <Robb underline Bean at gmx dot net> Projects: http://applaunch.sourceforge.net/ http://laymansys.sourceforge.net/ ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Gwyddion-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gwyddion-users
