TAKE 2: Spatial Selection Tools and Table Enhancements without attachment.

[Barry Windridge]

Below is a copy (without attachment) of an email that I posted on the
weekend and is currently waiting moderator approval:

Is there another mechanism to submit changes other than through emails?

Barry


COPY OF EMAIL

Attached is a zip file containing a number of enhancements to Thuban.
The enhancements are outlined below (and hopefully reflect changes to
the head revision on wald).

Select by graphics tools that I have previousely posted have been
fixed to handle multi-part shapes.

Logic added to make a selection a property of a layer, so that
multiple layers can have selections simultaneously.

Logic added to enable the layer selection highlight properties to be
modified on a layer basis. The properties that can be modified are the
selection fill and stroke colour, selection strike width and selection
fill pattern. These properties are saved/restored as part of the
session file. They can be accessed by the 'Selection' button on the
bottom of the layer properties dialog.

Clear Selection, Invert Selection, and Select All options have been
added to the layer context menu (right click popup) in the legend.

A 'Selection' menu has been added to the main menu. The Selection menu
has an options sub-menu displays a dialog that allows the select by
graphics tools to select features that are contained wholly within the
drawn graphic shape or any shape that is inside or intersects the
drawn graphic.  The dialog also allows the user to choose whether the
selection should (these options also apply to the select by layer
tool):
i) be a new selection
ii) be added to the existing selection
iii) use any features selected by a tool to be removed from an
existing selection
iv) select only features selected by the tool and also in the existing
selection for that layer

A spatial selection tool has been added that allows the following
types of selections
       1) Select points inside polygons
       2) Select points within a buffer distance from points in another layer
       3) Select lines intersecting a buffer distance from a points layer
       4) Select points within a buffer distance from a lines layer
       5) Select lines in one layer that intersect lines in another layer
       6) Select lines that are contained in polygon layer
       7) Select lines that are contained in or intersect polygon layer
       8) Select polygons that contain points from another layer
       9) Select polygons that contain part of a line from another layer
       10) Select points within a buffered distance of polygons
perimeter in another
      layer. This option has three sub options:
 i)    if an unsigned buffer distance is entered it will select points
inside and outside        o f the polygon that are within the required
distance.
ii)     if the buffer distance is preceded by a '+' sign then only points
outside the polygons that are within the buffer distance will be
selected
iii)    if the buffer distance is preceded by a '-' sign then only points
inside the polygons that are within the specified buffer distance will
be selected.

All of the above spatial selections can utilise the entire 'using'
layer or just the selected features of the 'using' layer.

Logic has been added to tableview.py to enable a table to be sorted on
a column by right clicking on a column and choosing from the
'ascending' or 'descending' options. Right clicking on the top left
hand blank area that is the inersection of the row labels and column
headings will allow the table to be returned to its "natural" order.
A sort button has been added to the top of the table that opens a
dialog to allow multiple columns to be chosen for sorting.

A "show selected"/"Show All" button has been added to layer tables.
This button will toggle between showing all rows in the table and only
showing selected features in the table, to make it easier to see which
features have been selected. If the table is only displaying selected
records then the doing a query or selecting features on the map will
automatically update the display to only show the currently selected
features. However if the user de-selects a row in the table it will
remain shown in the "show selected" display until another action takes
place to reset the display.