A Demo for the Boss (Selection Demo)

Here's a quick and easy demo that shows off the Mouse selection techniques in Manifold.  After you explain to your boss which part is the mouse, you can even let him or her play with making a few selections.  They love this stuff!

Practise this a bit on your own before showing the boss.   It's fun and it's easy. Click on the thumbnails to see the full image, and then use the Back and Forward buttons on your browser to go back and forth between this page's text and the full sized image, as desired.

1. Prepare a Base Map of the United States

We will use as a base map the US_Main map that's on the Manifold CD.  We've added to this map the US Census Bureau's population by state data for the years 1990 to 1997.  You can get the combined map in Manifold format by downloading it from ftp://ftp.dnai.com/users/m/manifold/US_Main_pops.ZIP   Unzip the file and open it in Manifold.  By default, the map is in unprojected form.  Convert it to a pretty projection such as Lambert Conformal Conic and color the states and background.  The Create a Map of US Regions case study provides step-by-step instructions on how to do this.  We suggest using a very plain graphics style for this demo, so that a "busy" map doesn't distract the boss.

2. Closed Box Selection 

The toolbar above shows how your selection modes buttons should be arranged.  From left to right, we're going to Replace the Selection with whatever we pick out with the mouse, we're going to select Areas only, and we're going to use Closed Box selection.

Draw a cursor box with the mouse as indicated in the image at right. "Drawing a cursor box" means clicking and dragging with the mouse to form a dotted outline.   Closed Box selection means we are going to pick out all the states entirely within the mouse cursor box.  From the illustration, it looks like we are going to select Wyoming (your boss will think it's maybe Colorado or Utah).

As soon as you release the mouse, the state of Wyoming will be highlighted in red, the default color used in Manifold to indicate an object is in the Selection.

3. Open Box Selection 

Change the cursor box  from Closed Box to Open Box as shown in the toolbar fragment above.  Open Box selects all objects any part of which is inside the mouse cursor box.  Open Box is very fast to use when you want to select many objects, because the mouse cursor box only has to overlap any part of them.

Click and drag a mouse cursor box that's approximately the same size as you did with the Closed Box selection in the previous step.   This is illustrated at right, where we see Wyoming highlighted in red from the previous step.

Immediately as you unclick the cursor box, the Selection will change to include all the States that have any part within the selection box.  Manifold is designed to work with huge numbers of objects, so even on slow Pentium machines the selection / redraw process for a map this simple is, like, instantaneous. 

Take a few moments here to do some open box and closed box selections.  Perhaps you could even let your boss take a swing at mousing away.   The difference between Closed Box and Open Box selection is simple, but it is a fundamental idea used in many CAD systems, and even in a few GIS systems too.

4. Let's See the Data

Click open Selection Table View to show the database contents for every object that's in the Selection.  Every map object is simply a record in Table View.    Manifold has regular Table View, which shows all the records in the map, and Selection Table View, which automatically shows only the data in the Selection.  You can click open as many simultaneous Table views as you like.

This particular map has columns for population data for every year from 1990 to 1997 for each state.  We'd suggest using the Show / Hide Fields button to hide most of the columns, so that only the names of the state, the abbreviation, population data for 1997, etc, are visible.  You can resize the table view a bit so that more screen space is available for the map.

5. Remove some States from the Selection 

Click on the "-" selection mode button to go into Subtract mode, and click on the Touch Selection button so that every time you click on a map object it will be subtracted from the selection.  Now, click on a few states and watch their records disappear from Selection Table View as their state is redrawn without the red selection highlighting.

The illustration at upper right shows the map after we've clicked on a few of the Selected states in Subtract mode using Touch Selection. If you like, click on a few more states to remove them from the Selection.

6. Add some States using Open Box again 

Click on the "+" selection button to switch into Add to Selection mode, and go back to Open Box.  The toolbar above shows the right settings.

Now, let's draw a big Open Box to select all the states in the West.  Add mode will add objects to whatever is already in the Selection.  The result, at right, will select all the states in the West.  Note that the Selection Table View window is also automatically updated when the selection occurs. 

Since there's a lot of data in the Selection Table View, you might want to take a moment to show your boss how easy it is to sort data in the window.  Click on any column heading to sort the table by that field.  SHIFT-click on any column heading to sort the database by reverse order using that field.  It's easy to click on the Name, Population column, etc and watch how easily the database is reordered.  There is a huge array of capabilities built into Table View, but that's enough for now.  This is a good prelude to what comes next, which is the use of SQL toolbar to find data.

7. Use SQL Toolbar to make a Selection.

OK, your boss was impressed with the column sorting.  He or she might have even asked "So how do I find a particular record?"  That's your cue to show how easy SQL Toolbar is to use.  Load up SQL Toolbar as in the illustration above.

[Note: Make sure the solver output mode is set to Replace Selection (the default, shown at right) in case you've been fooling with the solver modes as described in our Essay on Selection, another case study.  See that Case to get some examples of how to work with solver selection modes.]

You don't have to type in "[7/1/97]" since you can just pick that field name out from the pull-down menu.   The Census Bureau data enumerates the populations in the various states as of a given day in 1990 through 1997, so that's what they named their field names.  It's actually quite handy, because your boss probably remembers the ancient days of computing when everything had to have at most eight characters (all alphabetic or whatever, no symbols like slashes!).  You know, like when CP/M, dBase II, might  be astonished to learn that a modern system like Manifold can handle filenames with spaces in them and data attribute field names like "Roads and Highways".

When you push Select, Manifold's SQL engine goes out and selects all states that have '97 population less than or equal to three million.  It's instant, resulting in the display at right.  Because we've run SQL Toolbar in Replace Selection mode, the output of the solver becomes the current Selection.

8. Refine the Selection to just Western States using Intersect

Hey, that's fine, but we've also selected some states that are not in the West.  For some reason, the theme of this demo is Western states.    Of the states that have less than three million people in them, we'd like to pick out only those that are also in the West.  This is easy.

First, let's get ready to do some more Open Box selecting with the mouse, but this time we'll set the selection mode to Intersect.    The toolbar above shows the right settings, with the "&" selection mode button clicked to specify Intersect mode.

Now, let's draw an open box that includes the various Western states as illustrated at above right. Intersect mode means to select all those items picked out by the mouse cursor box that are also already in the Selection. 

Note: That's why we use an ampersand "&" pictograph for this button, because it is really a Boolean "AND" operation between what's picked out with the mouse and what is already in the Selection.   Caution: don't use words like "Boolean" with your boss. Save this for the comp.infosystems.gis news group.

The result is to pick out all the Western states that have a population less than three million, as illustrated at right.

9. Change our minds, get all States with population > 3,000,000

Suppose now we've changed our minds, and we decide we want all the Western States with populations greater than three million?  Or, perhaps we've done some analysis for all the States with sparser populations, and now we wish to repeat the analysis but on the Western states with greater populations?

There are several approaches.  We could simply select again using SQL toolbar.  It's really easy to do this, because SQL Toolbar is still loaded up with the values we used last time.   We could simply click on the "Not" button in front of the <= operator box and hit Select and get the states and then pick out the Western states again as we did in the previous step of this Case Study.

A simpler way is to use Invert with Selection mode.  That's the +/- button in the selection mode buttons.  Set up the selection mode buttons as shown above, and then use Open Box mouse cursor selection as illustrated above right.

Invert mode means to take all the objects specified with the Open Box and to invert them with whatever was in the Selection.  Any objects picked out that were not in the Selection get put  into the Selection.  Any objects that were in the Selection get tossed out. In an instant, we've "reversed" the Selection to pick out all States the 1997 populations for which were greater than three million.

The States are immediately redrawn in red selection color to show the new Selection and Selection Table View is updated, as illustrated at right.

10. Do Some Analysis to Impress the Boss

So far we've executed a series of Selections.  This is serious stuff, because the ability to do sophisticated Selections at lightning speed with a mix of mouse motions and solver commands is a key aspect of handling data.  (If you don't think Selecting is an important skill set, try finding something fast on Alta Vista).  But life is more than Selections.  Let's show the boss how easy it is to calculate results on the data set we've picked out.

Let's find the Standard Deviation of 1997 population for the States we've picked out.  Do this from the Solvers - Statistics menu, where we find a menu item for Standard Deviation.   This opens the dialog box illustrated at right.

Solvers in Manifold try to use a standard interface where pull-down menus in choice boxes present available options.  This avoids typing and speeds up the process.  Choose selection for the "Object Set".  This is simply what input you want to feed the solver.  You could select the name of a layer, etc, in this box.  We'll use selection because we want to feed the solver only the data from the States we have selected.

Your boss might be impressed by the Formula: box, or he or she might simply get confused.  For us tech heads, this is simply the field on  which standard deviation is to be computed.  It's labled "Formula" because Manifold solvers are part of the Manifold formula-calculation engine system, where just about any input box can be fed an Active X formula.  In this case we simply choose the name of the 1997 population field from the pull-down menu. But, we could use this box to specify an input argument in a more sophisticated way.

Seriously, you can actually write things like ([hispanic_population]/[total_population]) * 100 into the solver Formula: box and Manifold will compute this on the fly for each State while calculating the standard deviation of the values of this expression. [Editor's note: assuming, of course, you have fields called "hispanic_population" and "total_population" in your dataset...]  If your boss is still cool, you can explain this.  Manifold's ability to automatically calculate formulas within solver boxes, and even within any field box in Table View, is one of the most intense and far-reaching aspects of the system.

Click OK and the Standard Deviation solver will leap into action.  Instantly, the standard deviation for the 1997 population of the Western states selected will be computed and placed in Results History.  Click open the Results History window to see the result, as shown at right.

Your boss may ask, "Why does it make you open another window to see the standard deviation?"  That's a good question that opens the door to an explanation of a key Manifold feature that provides convenience, power, and flexibility.

Manifold writes out solver results to the Results History window so you always have a "ticker tape" of previous results, just like the paper tape in a printing calculator. The Results History ticker tape runs even if the window isn't open. This is important, because many solvers create serious information that won't fit into a simple dialog output box.  Such solvers not only write out lists of results to Results History, they also plant a results Icon in Results History.   You can go back to any spot in Results History and grab the results from a previous solver run by grabbing the icon, and then use those results to... well, make a Selection, or as input to another solver.  None of this is possible if the solver simply reported the results as ordinary Windows dialogs do, and then, if you didn't scribble the results down manually, they'd disappear.   Why scribble down results by hand when the computer is just waiting to keep track of them for you at a few hundred million operations per second?

If you like, of course, run a few other solvers.   Statistics solvers seem to be popular for demos since everyone usually understands what they mean right away.  Plus, they work well with demographic data like population that are used in entry-level demos.

11. Make the Map Pretty

OK, enough with Selection and analysis.  Let's make the map pretty.  We're going to skip the step-by-step sequence for this section because other Case Studies deal with formatting.  The Help system also discusses autoformatting ("thematic" coloring by value of data attributes) at great length. It's easy, and it's fun.

Some suggestions:

1) Color the Selected states using Format Selection and autoformat them into four or five different color intervals.  Use restraint in choice of area patterns.  "Earth tone" colors with low saturation seem to be stylish these days, or at least seem so to us.  Avoid overly bright, primary colors.

2) Use Format Labels to add State abbreviation labels to each state.  Don't forget to show the boss how easy it is to simply drag them to any desired location if you don't like where Manifold puts them.

2) Create some unbound labels using Insert Label.   In the example map, we've used Insert Label to create the title, a small note on population data vintage, and a really tiny copyright message.  Don't forget to show your boss how easy it is to right-click on a label and to use Format Label or Edit Label Text... from the right mouse menu to change the characteristics of a label.  Show how millions of colors may be used, various label font and box styles can be changed, the font characteristics may be changed, and how easy it is too do all this.

Like what you see? Now is the time to buy Manifold System and get all these capabilities for yourself.  It's only $145 and it totally outperforms ancient systems from an earlier era.  You get more power, better ease of use and a spectacularly driven engineering organization working to serve you better.  While you are at it, why not order a copy of TIGER/Line 1997 as well? Visit the Manifold.net Online Store for a quick, easy, and secure purchase of Manifold products, or (in the US) call 800-556-5919 to order by telephone (9-5 PST).  Don't forget to stock up on solver package products like 3d View and Business Tools as well!

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