Greetings:

I posted an inquiry about how GIS users deal with time-series data and
cross-tabulation reports.  I got hardly any responses, leaving me to wonder
if we are an eccentric outfit here at HydroQual. I will restate the problem:

We deal with samling points, fixed locations, at which water quality samples
are taken over long periods of time, for a variety of parameters (dissolved
oxygen, BOD, TOC, etc.).  These data are generally tabulated as follows:

                Station1        Date1           Parameter1      Value
                Station1        Date1           Parameter2      Value
                Station...      ...             ...             ...

In order to make thematic maps, we need to get the data into ArcView or
ArcMap in this form:

                Station1        AvgParameter1           AvgParameter2
AvgParameter3...
                Station2        ...
                ...

That is, a unique record for each station, with the columns having the
average (or the max, min, etc.) value for each parameter over a selected
time period.  This is easily done in MS-Access with the crosstabulation
report.  Can't do it in ArcView unless you write a tedious program.  The
summation function in AV3x will do it for one parameter at a time.  (You
could do it successively, join the tables, then make the map - a pain.)

Farley Klotz wrote that his group does the cross tab in Access and exports
the result to a *.dbf file, which is then imported to AV and mapped.  I
prefer to do it dynamically, but I find that the ODBC link to Access
cross-tab queries is slow.  It is especially slow in ArcMap.

Cheers,

Gary