User Tools

Site Tools


metertimeseriesdataformat

This is an old revision of the document!


Table of Contents

Goal

The aim is to specifiy and create a generic software library for timeseries with measured data. The library must be able to store timeseries with associated metadata. The library should consist of two parts:

  • An interface for other components that would like to store or access timeseries data. The library must enforce certain restrictions on incoming data, such as a valid timestamp. For accessing the data an database-cursor like interface seems appropriate.
  • The library must be able to characterize the data based on an empirical cumulative distribution function (ecdf). This means that min/max, average, median etc. should be represented based on the full data, not only the data that has been reduced in resolution. NOTE: This is currently an open issue, to be solved using complex event processing techniques. See e.g. http://subs.emis.de/LNI/Proceedings/Proceedings65/GI-Proceedings.65-24.pdf.
  • The library must store metadata for a given sensor, including free-text comments.
  • The library must perform sanity checks.

Requirements

The library is to be used in a wide range of applications, ranging from recording data locally (on a small embedded device like the Chumby) to the webservers of the project. It must therefore be written in C++, as portable as possible. It is safe to assume a POSIX architecture, the boost libraries can also be used.

TODO: Specify usecases in more detail.

Metainformation

  • Description
  • meterID
  • Unit
  • Timezone
  • time-reference: left-justified or right-justified
  • Scaling Factor (e.g. SCALING_FACTOR = 10.0)
  • Offset/Bias
  • Missing Value (e.g. MISSING_VALUE = -1) or (better) don't store missing values. Whats not stored is not available.

Data

  • Timestamp (unixtimestamp)
  • Value (floatingpoints)

Version 0.1

The development of this library will be an ongoing process. In the first version, a simple usecase should be satisfied:

metertimeseriesdataformat.1295866774.txt.gz · Last modified: 2012/10/30 10:38 (external edit)