[udig-users] Automatically updating a field in a set of selected records

[Michael Goldstein <michael.goldstein7@xxxxxxxxxxx>]

Can you perhaps point me to the right features in uDig?  I'm starting up a new project, and feel that uDig is the best open-source tool for what I need to do IF I can figure out how to implement the last step.

My task is to mark-up a set of stream segments in a large shape file based on reading and interpreting a paper list published by a state bureaucracy.  The paper list is missing critical information that would make it easily automatable, so interpretation and human translation is, unfortunately, essential.    The list tells me the name of a stream, and the name of the stream it flows into, and the basin in which both are located.  The shp file is huge, with more than 80,000 features.  One stream in the printed list typically translates to 20-30 features, and sometimes more, in the shp file.

What I need to do is:

1. Search for the stream name in the attribute table.  Since stream names are rarely unique, even within a single watershed, I have to muck around visually a bit to make sure I've got the right segment(s) identified by checking out the next-order streams, the basins, etc.  It's made worse by the fact that the shape file isn't perfectly coded, so sometimes the right stream flows into an "unknown stream", and I can only confirm the name of the second order stream (and by extension confirm the identity of the subject stream) by scanning up and down segments of the next order stream until I find one with a recorded name.

2. Select all of the features which correspond to the reach in the list.  I can usually construct a simple query to do this, using various attributes in the table, once I've visually confirmed it's the right one.

3. [THIS IS WHERE I NEED HELP]  Set a flag in one field of each record selected in step 2 to mark the reach.  The "flag" is an alphanumeric code, 2-4 letters long, e.g. 'DUIV'.  Ideally I'd like to edit all of the records automatically, as in an update query.  Grass, for example, has a function that lets me do this but the GRASS UI is overwhelmed by steps 1 & 2 for such a large dataset.  Of course, sometimes there will be only one or two features that need flagging, in which case editing it directly in uDig's table editor would be faster.

I suppose, based on the "marketing" docs I read, that it should be possible to set up a project where the attribute table for the layer was maintained in MySQL, and I could use update queries in PHP MyAdmin to execute the changes.  I have little confidence that I could set this up properly, especially as I want to use uDIG's table view and search capabilities at the same time.  

If there were an good, internal update tool internal to uDig, I'm sure that would be preferable to phpMyAdmin....

As you have no doubt gathered, I'm a data analyst, not a programmer.  I can construct simple SQL queries, but that's about as much as I want to do in terms of creating code.

Any thoughts you have would be appreciated.

Michael