Enlist labels as "virtual members" of the attribute table?

Nov 14, 2011 at 3:13 AM
Edited Nov 14, 2011 at 3:22 AM

My current project is to map selected statistics from the February 2012 Chicago municipal elections.

The is to map not only raw data (how many votes were cast in this precinct, how many were cast for each candidate, etc) but also to map complex data (how big a lead did the winner have, what percentage of the votes did he garner, etc).

The map will have one layer for each type of statistic, and each layer will colorize one statistic's value for each of the 2574 precincts in Chicago.

As far as I can tell, MapWindow currently requires that I add 2574 values to the attribute table for each new statistic that I want to display.  This will entail a large and ever-expanding attribute table, holding more and more values as people request more and more statistics.  Or else it will require that each new statistical layer have its own,new attribute table, offering is single pertinent attribute.

But help may be in sight.

One nice feature of MapWindow 4.8.6 is that labels need not mirror exactly one attribute, but can be computed from a formula referencing several attributes.

If this feature can be slightly extended, it would be a great boon for my project.

The desired extension is this: Allow a layer's labels to serve as "virtual attributes"--as virtual members of the layer's attribute table.

This would allow complex statistic to be computed on-the-fly from raw data in the attribute table, and then, like any other attribute, to be used in colorizing the map's terrain.

This holds great advantages for the map administrator:

* A label formula takes up orders-of-magnitude less disk space than the corresponding individual attribute-table entries.

* Because the label formula is not stored in the attribute table, the attribute table itself has no need to be modified.  As a result,

  **  One and the same attribute table can be employed for all the statistical layers.  This saves much disk space.

  **  The administrator has no need to modify or create an attribute table for each new statistic.  This saves the administrator much time.

  **  The administrator has fewer attribute tables to maintain.  This, too, saves the administrator much time.

So, is it possible to extend the label feature in this way?

Coordinator
Nov 14, 2011 at 2:37 PM

Thanks for this clear 'real-world' example.

We will put it on the TODO list for v4.9.

Thanks,
Paul

Nov 14, 2011 at 3:50 PM

I agree. A very nice 'real-world' example and definitly a nice tool to have in MW.

Apr 4, 2012 at 3:51 PM

Any idea when v4.9 will be ready for beta testing?  I'm eager to use the "virtual attribute" feature.

Thanks,

Roy

Coordinator
Apr 4, 2012 at 4:14 PM

Roy,

v4.9 will not be ready for months. Not only is the ocx hugely extended but the GUI (MapWindow.exe) needs to be rebuild, business objects need to be introduced (updated versions of MapWinGeoproc.dll).

We're currently very busy organizing the next conference (http://www.mapwindow.org/conference/2012/index.php) after that (July) I'll start with the GUI.
Feel free to start rebuilding a slim C# GUI if you have the skills.

--
Paul

Aug 2, 2012 at 7:14 PM

Paul,

Now that the 2012 conference is over, I imagine work is resuming on v4.9.

Does it look like v4.9 will include the "virtual attribute" feature?

(Unfortunately, I don't program in C, or I'd love to give a hand with this project.)

Thanks,

Roy

Coordinator
Aug 3, 2012 at 8:11 AM

Roy,

We're working on MapWinGIS v4.9 already. That is the 'work-horse' of MapWindow, written in C++.
We've started a MapWindow Summer of Code 2012: http://www.mapwindow.org/SummerOfCode/2012/participants.php

For the GUI and business objects of MapWindow v4.9 (mapwindow.exe) we are in the process of describing the new architecture. We hope to have a first review version ready at the end of next week.

I'll ask Sergei if your request needs to be in the ocx (MapWinGIS) or in the plug-in (C#). If it is in the ocx I'll create a task of it for the Summer of Code.

Thanks,

Paul

Aug 3, 2012 at 10:14 PM
Paul,

That would be great.

Thanks much,

Roy


From: [email removed]
To: [email removed]
Date: Fri, 3 Aug 2012 00:11:34 -0700
Subject: Re: Enlist labels as "virtual members" of the attribute table? [mapwindow4:279313]

From: pmeems
Roy,
We're working on MapWinGIS v4.9 already. That is the 'work-horse' of MapWindow, written in C++.
We've started a MapWindow Summer of Code 2012: http://www.mapwindow.org/SummerOfCode/2012/participants.php
For the GUI and business objects of MapWindow v4.9 (mapwindow.exe) we are in the process of describing the new architecture. We hope to have a first review version ready at the end of next week.
I'll ask Sergei if your request needs to be in the ocx (MapWinGIS) or in the plug-in (C#). If it is in the ocx I'll create a task of it for the Summer of Code.
Thanks,
Paul
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