[EpiData-list] Important milestone in EpiData development

epidata-list at lists.umanitoba.ca epidata-list at lists.umanitoba.ca
Thu Aug 20 05:22:52 CDT 2009


Dear All

An important achievement on the current development path for EpiData 
Software has been achieved. On the test page a new build of the EpiData 
Core test module has been placed for the Mac OSx. Within the next week 
or so a Mac with PowerPC processor should arrive finalising the current 
operating system support plans.

The conversion from windows/linux to Mac went very smooth and this is a 
final indication that the decision last year to rewrite core modules by 
using the open-source pascal compiler FreePascal - and the programming 
tool Lazarus (IDE) was a good choice.

Users are highly encouraged to test the following:
a. How does the Core module perform on different operation systems 
(linux/linux64/windows variants/Mac).
b. Import and Export any or all of the supported data formats.
      - guessing raw text and delimited files (csv, txt etc)
      - dbase III
      - Stata - from version 5-10 +11
      - EpiData rec+chk files

In particular in relation to dates, string fields, real, integer 
problems. The test version is available from:
http://www.epidata.dk/testing.php

Following the test work will now progress with implementation of 
translation principles and extension of more data formats . The plan is 
to add handling of spreadsheet formats - as expected the proprietary 
black box data formats of M$ used in excel sheets are not documented, 
but some indirect ways of including this is possible. More news on this 
later.

----------------------
Further notes on current development (technical):

The real challenge in the conversion obviously comes later when 
dataentry and analysis functions are implemented on top of the core 
module, but is reassuring to see that the core module can actually work 
on different systems. But I wish that all aspects of this are taken into 
account before continuing the current modules.

Work has been done to see whether a new EpiData format should be 
implemented. The problem is that when shifting from strict Ascii format 
of characters to UTF-8 and support of several Operating Systems some 
technical problems  demands clarification.

Possible solutions are:
1. A new fixed format taking care of the varied length aspects of UTF-8
2. A completely new variable length EpiData data format
3. Application of an open xml based standard - e.g. the Data Archive 
format (DDI-3.0)
      see: http://www.icpsr.umich.edu/DDI/
4. Use of another software format, e.g. Stata10 (but this would not 
solve the multi language character problem)

Experimentation has been done with SAS transport format, but this is not 
feasible since parts of this are insufficiently documented. A solution 
will come up and further information given to the list before doing so.

regards

Jens Lauritsen
EpiData Association


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