The spectrum service group provides operations that revolve around spectra in SpecTcl. This service group allows you to request information about spectra, create and delete spectra.
The base URL for this service group is
Produces information about the spectra whose names match a pattern with glob wildcards characters. The filter optional parameter provides the value of this pattern. If not supplied it defaults to * which matches all spectra.
The detail attribute of the returned object is an array of objects, one object for each matching spectrum. Each of these objects has the following fields that, taken together, describe the spectrum:
The spectrum name.
The SpecTcl spectrum type code.
The SpecTcl spectrum parameter definitions. This is provided as an array of strings.
This is an array of objects that describe the SpecTcl axes. Each object has the attributes low for the axis low limit, high for the axis high limit and bins for the number of bins on that axis.
The SpecTcl channel type code (e.g. long).
Deletes a single spectrum. The name parameter provides the name of the spectrum to delete.
On success the detail field is empty. The non success returns include:
missing parameter. The name parameter was not supplied.
not found. There was no spectrum with the name provided.
command failed. The spectrum -delete command failed. detail contains the error message returned by the command.
Creates a new spectrum. The spectrumto be created is defined by the query parameters, most of which are mandatory:
The name of the new spectrum. This must not be the name of an existing spectrum.
The spectrum type code e.g. 1 for a 1-d spectrum.
The parameters expressed as a space separated list.
The axis specifications. This is a space separated list of SpecTcl axis specifications e.g.: {0 1023 100} {0 1023 200}.
The spectrum channel type, defaults to long.
On success, the detail field of the returned objexct is empty. Several types of failures are directly tested for:
A mandatory parameter was not supplied.
The spectrum -create command failed. detail is the error message from that command.
Clears the counts in a set of spectra. The pattern parameter supplies a glob patternt hat the cleared spectra match. pattern defaults to * which clears all spectra
This operation has no failure returns. The worst thing it can do is to clear nothing (no matching patter). The detail attribute of the returned objetct is also empty
Returns the contents of the a spectrum. The contents of a spectrum are sufficient to reconstruct the spectrum channels and overflow statistics. The only parameter is the mandatory name parameter which is the name of the spectrum to return.
There are some significant differences in what can be returned. These differences depend on the underlyng spectrum type (1 or 2d) and the version of SpecTcl the REST server is running on (4.0 or earlier).
Prior to SpecTcl 4.0, spectra did not maintain over/undeflow statistics. The REST interface for those version of SpecTcl produced an array of channel objects for the channels with non-zero counts as the value of the detail attribute:
Channel objects have the following attributes:
The X channel number.
The Y channel number.
The number of counts at that channel.
Beginning with SpecTcl version 4.0, the detail attribute became an object with the attributes channels and statistics. The channels attribute contains the array of channel objects and the statistics attribute contains an object that describes the over/underflow statistics for the spectrum. Its attributes are:
The number of times an X parameter value was below the X axis low limit.
The numer of times a Y parameter value was below the Y axis low limit.
The number of times an x parameter was above the X axis high limit.
The number of times a Y parameter value was above the Y axis high limit.
Two optimizations are performed. Channel objects are only present for non-zerof channels. 2d spectra may be emitted with the Content-encoding deflate. In that case the special header Uncompressed-Length provides the number of bytes required to hold the uncompressed JSON after defation.