| 12 |
<author> |
<author> |
| 13 |
<firstname>Jan-Oliver</firstname><surname>Wagner</surname> |
<firstname>Jan-Oliver</firstname><surname>Wagner</surname> |
| 14 |
</author> |
</author> |
| 15 |
|
<author> |
| 16 |
|
<firstname>Frank</firstname><surname>Koormann</surname> |
| 17 |
|
</author> |
| 18 |
<copyright> |
<copyright> |
| 19 |
<year>2003</year> |
<year>2003</year> |
| 20 |
<holder>Intevation GmbH</holder> |
<holder>Intevation GmbH</holder> |
| 599 |
The available projections are listed on the left. If the layer |
The available projections are listed on the left. If the layer |
| 600 |
or map already has a projection it will be initially highlighted |
or map already has a projection it will be initially highlighted |
| 601 |
and will end with <varname>(current)</varname>. Selecting |
and will end with <varname>(current)</varname>. Selecting |
| 602 |
<varname>None</varname>will cause Thuban to use the data as |
<varname>None</varname> will cause Thuban to use the data as |
| 603 |
it appears in the source file and will not use a projection. |
it appears in the source file and will not use a projection. |
| 604 |
</para> |
</para> |
| 605 |
</section> |
</section> |
| 635 |
|
|
| 636 |
<chapter><title>Table Management</title> |
<chapter><title>Table Management</title> |
| 637 |
<para> |
<para> |
| 638 |
|
Thuban distinguishes two different types of tables: Attribute tables |
| 639 |
|
(which belong to a layer) and usual data tables. Both provide in |
| 640 |
|
general the same functionality with the difference that actions on an |
| 641 |
|
attribute table might also effect the map display. |
| 642 |
|
</para> |
| 643 |
|
|
| 644 |
|
<section><title>Table View</title> |
| 645 |
|
<para> |
| 646 |
|
Thuban provides a standard dialog to display table contents, the |
| 647 |
|
Table View. The view falls into five sections: The title, selections, |
| 648 |
|
the table grid, export functions and the status bar. |
| 649 |
|
</para> |
| 650 |
|
<para> |
| 651 |
|
The title bar identifies the table with it's name. |
| 652 |
|
</para> |
| 653 |
|
<para> |
| 654 |
|
The functions box let the user perform simple analysis on the data |
| 655 |
|
based on comparisons: First choice must be a field identifier of the |
| 656 |
|
table, the second choice determines the type of comparison. The third |
| 657 |
|
choice can be either a specific value (interpreted as numerical |
| 658 |
|
or string depending on the type of the first field) or a second field |
| 659 |
|
identifier. Thus you can perform analysis like selecting all |
| 660 |
|
records where "population > 10000" or |
| 661 |
|
"cars_per_habitants < bike_per_habitants" (note that the field names |
| 662 |
|
are only explanatory, the currently considered dbase files allow only |
| 663 |
|
11 character field names). |
| 664 |
|
|
| 665 |
|
Selections can be combined, either by applying a selection only on |
| 666 |
|
a previously selected set of records or by adding the results of a |
| 667 |
|
selection to a previous set. The default is that a selection replaces |
| 668 |
|
earlier results. |
| 669 |
|
</para> |
| 670 |
|
<para> |
| 671 |
|
The table grid shows the contents of the table (a record per column), |
| 672 |
|
with highlighted selection results. Columns and rows can be resized. |
| 673 |
|
</para> |
| 674 |
|
<para> |
| 675 |
|
The contents of a table can be exported into a file, either dbase |
| 676 |
|
format (DBF) or comma seperated values (CSV). The 'Export' button |
| 677 |
|
raises a file dialog to specify a path and file name, the export type |
| 678 |
|
is determined by the file extension (either .dbf or .csv). |
| 679 |
|
|
| 680 |
|
The 'Export Selection' button works similar but exports only the |
| 681 |
|
selected records. |
| 682 |
|
|
| 683 |
|
The 'Close' button closes the table view. In difference to the |
| 684 |
|
menu item 'Close' just the dialog is closed, the table is still loaded |
| 685 |
|
in Thuban. |
| 686 |
|
</para> |
| 687 |
|
<para> |
| 688 |
|
The status bar displays some statistics about the table and optional |
| 689 |
|
selection results. |
| 690 |
|
</para> |
| 691 |
|
</section> |
| 692 |
|
|
| 693 |
|
<section><title>General Functionality (Menu Table)</title> |
| 694 |
|
<para> |
| 695 |
|
The general functions affect all tables open in Thuban. Attribute |
| 696 |
|
tables are considered as here as usual data tables (with the exception |
| 697 |
|
that they cannot be closed). |
| 698 |
|
</para> |
| 699 |
|
<section><title>Open</title> |
| 700 |
|
<para> |
| 701 |
|
The 'Open' item raises a file dialog to let you select a |
| 702 |
|
dbase file from the file system to be loaded into Thuban read-only. |
| 703 |
|
On OK the selected file is loaded and a table view is opened. |
| 704 |
|
</para> |
| 705 |
|
</section> |
| 706 |
|
|
| 707 |
|
<section><title>Close</title> |
| 708 |
|
<para> |
| 709 |
|
The 'Close' item raises a dialog listing the currently open |
| 710 |
|
data tables (loaded via the 'Open' functionality'). You can select |
| 711 |
|
tables which are dereferenced on confirmation. Since tables are |
| 712 |
|
opened read-only the contents of the tables are not affected. |
| 713 |
|
|
| 714 |
|
A still open table view is closed as well. |
| 715 |
|
|
| 716 |
|
Tables used in a join can not be closed. |
| 717 |
|
</para> |
| 718 |
|
</section> |
| 719 |
|
|
| 720 |
|
<section><title>Rename</title> |
| 721 |
|
<para> |
| 722 |
|
Changes the table title. |
| 723 |
|
</para> |
| 724 |
|
</section> |
| 725 |
|
|
| 726 |
|
<section><title>Show</title> |
| 727 |
|
<para> |
| 728 |
|
The 'Show' item raises a list of available tables (explicitly loaded, attribute tables, results of a join). Selected tables are show in |
| 729 |
|
tables views on 'OK'. |
| 730 |
|
</para> |
| 731 |
|
</section> |
| 732 |
|
|
| 733 |
|
<section><title>Join</title> |
| 734 |
|
<para> |
| 735 |
|
The 'Join' item raises a dialog to specify the two tables to be |
| 736 |
|
joined. The join results in a new table named 'Join of "left table" |
| 737 |
|
and "right table"'. |
| 738 |
|
|
| 739 |
|
The dialog let you select the two tables to be joined and the two |
| 740 |
|
fields the join has to be performed on. By default the new |
| 741 |
|
table contains only those records which are mathced by the join. |
| 742 |
|
|
| 743 |
|
If you want to preserve the records of the left table you can perform |
| 744 |
|
an outer join. The fields from the right table for records not |
| 745 |
|
matched by the join are filled with <varname>None</varname> in this |
| 746 |
|
case. |
| 747 |
|
</para> |
| 748 |
|
</section> |
| 749 |
|
|
| 750 |
|
</section> |
| 751 |
|
<section><title>Attribute Tables</title> |
| 752 |
|
<para> |
| 753 |
|
To clearly separate between both types, Thuban provides functionality |
| 754 |
|
regarding the attribute tables under the Layer menu. |
| 755 |
</para> |
</para> |
| 756 |
|
|
| 757 |
|
<section><title>Show Table</title> |
| 758 |
|
<para> |
| 759 |
|
Opens the attribute table of the currently active layer in a table |
| 760 |
|
view. |
| 761 |
|
|
| 762 |
|
In addition to the functionality described above selections |
| 763 |
|
affect also the map display: objects related to selected records |
| 764 |
|
are highlighted. |
| 765 |
|
</para> |
| 766 |
|
</section> |
| 767 |
|
|
| 768 |
|
<section><title>Join Table</title> |
| 769 |
|
<para> |
| 770 |
|
In difference to the join described above the join results not in a |
| 771 |
|
new table. The attribute table of the currently active layer is the |
| 772 |
|
left table and other tables are join to this table. Results of the |
| 773 |
|
join in turn are available for classifications. |
| 774 |
|
|
| 775 |
|
As a consequence of the above the join cannot result in less |
| 776 |
|
records than the source attribute table. You are warned if the |
| 777 |
|
right table does not fulfill this constraint. Use an outer join |
| 778 |
|
in such cases. |
| 779 |
|
</para> |
| 780 |
|
</section> |
| 781 |
|
|
| 782 |
|
<section><title>Unjoin Table</title> |
| 783 |
|
<para> |
| 784 |
|
As said above, a usual table can not be closed while still used in |
| 785 |
|
a join. While the join table resulting from a join of usual tables |
| 786 |
|
can be simply closed (and therewith dereferences the source tables) |
| 787 |
|
this is not possible for attribute tables. |
| 788 |
|
|
| 789 |
|
Hence joins on attribute tables must be solved explicitely. This is |
| 790 |
|
what the 'Unjoin' item is used for: The last join for the currently |
| 791 |
|
active layer is solved. |
| 792 |
|
</para> |
| 793 |
|
</section> |
| 794 |
|
|
| 795 |
|
</section> |
| 796 |
</chapter> |
</chapter> |
| 797 |
|
|
| 798 |
<chapter><title>Trouble Shooting</title> |
<chapter><title>Trouble Shooting</title> |
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