NavTable
¿ Qué es NavTable ?
NavTable is a gvSIG extension to display in an agile way the alphanumeric elements of vectorial layers. It allows seeing the features of an element in a vertical table besides editing, navigating and quick filtering the values of a layer.
NavTable is released under a GPL v3 license. It has been created by CartoLab, the Cartographic Laboratory from University of A Coruña. Feel free to send us comments, suggestions, bug reports, etc.
Listado de características
- Display data from vectorial layers in vertical align
- Edit alphanumeric values (tested with ESRI Shapefile and PostGIS)
- Navigate between elements: next, previous, ...
- Allow to navigate only by selected elements
- Zoom to the elements: manual and automatic
- Allow zoom with fixed scale
- Select and unselect elements
- Alphanumeric editing of values
- Copy attributes from last register or from selected
- Create and drop elements
- Length and area of a element is calculated
- Available in spanish, galician, english and french.
Interfaz
To activate NavTable you must select a vector layer in the gvSIG ToC (Table of Contents) and click the button NavTable 
.
NavTable interface has the following areas:
- Top: basic adjustments and filter checkboxes.
- Central: view and edit data in each record.
- Bottom: navigate bar, save button and others practical buttons.
NavTable can be used for editing and display alpha-numeric tables, which have no associated geometry. For these cases, NavTable icon in the toolbar will be blue 
. The title of the NavTable window for tables without geometry has a '*' to distinguish it from normal tables.
Navegación
NavTable scrolls through the records and features in a friendly way. You will find the navigation bar at the bottom of NavTable's window.
With these buttons you can:
- Go to the first record
- Go to the previous record
- Go to the next record
- Go to the last record
- Go to any record using the box located between the buttons described above. It shows the number of the records you're currently viewing. If you enter a new value here you will see the corresponding record. Next to the position of the box there is a number indicating the total amount of records in the table.
If you are working in the central area of NavTable (click on any row) you can use the buttons “right”or “left”, “home” or “end” to change the record that you want to see.
Selecting elements
If you click on the checkbox "selected" the navigation buttons will work only for features that are previous selected. If a feature is selected, the bottom area of the NavTable Window will be highlighted in yellow. In between parentheses the number of selected records can be seen next to the whole number of records.
In this image you see an example explaining how this function works: record 8 for a layer with 20 records is displayed where 7 records are selected.
If the checkbox "selected" is activated without any selected feature, all records will be shown empty and the box will not display any number. and
.
The option "select" is another interesting tool you can find next to "selected" in the Nav Table menu. If you activate the checkbox next to "select", the attributes you are visualizing will be selected and highlighted in the view. In the case that other features were selected, this option will turn them unselected and will select only the register you are visualizing.
On top of the NavTable Window there is the button "Filter" . If you press it, a dialogue window will appear in which you can define exactly what you want to select (attributes and calculations). If you click on "clear selection"
all selections will be turned off and no features will be selected.
Zoom to feature
If you click on the zoom button 
the feature will be displayed in the center of the view, referring to the record you are working with at that time. The scale of the view will be changed to have a good visualization of the data. In case you are working with a point layer, a scale size will be chosen that allows to see also the surroundings of the point.
With help of the button "always zoom" next to the checkbox "select", Navtable will zoom to each feature referring to the record you are visualizing. If you click on "fixed scale" as well, Navtable will zoom to the feature and display it in the center of the view, but the scale will always remain the same. It is possible to change the scale value introducing a new one in the "scale bar" of gvSIG. This is shown on the buttom right of the gvSIG view, next to where the coordinates are displayed.
Tip: The options "always zoom" or "fixed scale" together with "select" is a very interesting way of navigate through the features of a layer.
Edición
The main new functionality in Navtable is that you don't need to start the editing mode for a layer if you want to edit it. You should follow these steps to edit the table:
- Make double click on the register you wish to work with (or click on the space bar). Now you are in editing modus and you will be able to modify this record.
- Modify the data by entering a new value
- Click on the "save" button
.
After that, the new value will be saved. It's important to consider these special cases if you want to save the edition:
- with boolean fields you can only use true or false (the expression is not case sensitive). If you enter another value, the original one will be saved.
- If you try to save a value into a not appropriate field (for example from type „text“ into type „numerical“), the original value will be written.
- If you want to save an empty text, the default value will be saved. But if the field is from type „string“, the record will be saved with an empty value.
With Navtable it is also possible to use options for advanced editing. For example you can copy and paste records. For that you should select the record you want to copy first and click then on the button "copy selected feature" 
. The data will be modified when you click on the button "save".
Removing records
It is possible to delete the record you are visualizing with Navtable if you click on the button "delete feature" 
. If this record has an associated geometry feature (graphical element), this one will be also deleted.
Adding records to alphanumerical tables
For tables which aren't associated to a layer, Navtable has this button 
. If you click on it, after the last one of the table a new record will appear.
Visualización de nombres largos
As you know, the dbf format doesn't allow field names with more than 10 characters. This limitation could be solved using alias for these fields. This option is also available for layers stored in a geodatabase.
If you wish to use this functionality you will need to create a text file with the same name as the layer in which you want to use "alias" names. Save this text file in the folder "alias" that was created when installing Navtable.
When installing gvSIG, a folder with the name gvSIG will also be created:
On Windows it is usually installed here "C:Documents and Settingsuser"
On GNU/Linux you will find it here: "/home/user/gvSIG"
When installing Navtable, a folder with the Name "Navtable" is saved to the "gvSIG" folders. At the Navtable folder you will find the "Alias" one, where you should save the text file mentioned above.
In this file you can define long names or alias for the field names.
Name_original_field=long_name
It's only necessary to describe a row for the fields you want to define an alias name for. The order of the lines isn't important, that means, you don't need to follow the same sequence like the field's names of the table.
When Navtable is opened, the according "alias" text file will be found automatically. If new names for the fields are available there, Navtable will use these ones instead of the original names.
Example: There is a dbf file with the following fields:
We define an alias text file with the same name as the shape file: Afg_district.alias in this case. In this file we will write the following text:
prov_code=province code distr_code=district code
This file Afg_district.alias will be saved in the same folder as the file Afg_district.shp. Now we can open the table of this layer with Navtable and can see the following:
Important for Windows:
Windows doesn't show the file extension by default. For this reason for a new alias text file the name of the file will be probably name_layer.alias.txt and Navtable will not be able to read this alias file.
In order to have a correct result for this functionality we recommend you to deactivate the option hide hidden files and folders. You can make this in Windows Explorer: Extras > File Options > View > Advanced Settings > Hidden Files and Folders
Más información sobre NavTable
NavTable is hosted by the OSOR Forge [1]. On this page you can find useful information about the project and also related documents, mailing lists, bug reporting system, etc.
In the section "Future Work" on the project website you will find some of the things we want to incorporate in NavTable in the near future.
| [1] | http://navtable.forge.osor.eu/ |
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