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| − | <H3>
| + | --[[利用者:Sanak|Sanak]] 2009年10月4日 (日) 08:10 (UTC)このページは削除予定です。 |
| − | Actions Tab
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| − | </H3>
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| − | | + | |
| − | <P>
| + | |
| − | QGIS provides the ability to perform an action based on the attributes of a
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| − | feature. This can be used to perform any number of actions, for example,
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| − | running a program with arguments built from the attributes of a feature or
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| − | passing parameters to a web reporting tool.
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| − | | + | |
| − | <P>
| + | |
| − | Actions are useful when you frequently want to run an external application or
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| − | view a web page based on one or more values in your vector layer. An example
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| − | is performing a search based on an attribute value. This concept is used in
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| − | the following discussion.
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| − | | + | |
| − | <P>
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| − | Defining Actions<A NAME="410"></A>
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| − | | + | |
| − | <P>
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| − | Attribute actions are defined from the vector Layer Properties dialog. To
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| − | define an action, open the vector Layer Properties dialog and click on the
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| − | Actions tab. Provide a descriptive name for the action. The action
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| − | itself must contain the name of the application that will be executed when the
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| − | action is invoked. You can add one or more attribute field values as arguments
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| − | to the application. When the action is invoked any set of characters that
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| − | start with a % followed by the name of a field will be replaced by the value of
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| − | that field. The special characters %% <A NAME="414"></A>will be replaced by the value
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| − | of the field that was selected from the identify results or attribute table (see
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| − | Using Actions below). Double quote marks can be used to group text into a
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| − | single argument to the program, script or command. Double quotes will be
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| − | ignored if preceded by a backslash.
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| − | | + | |
| − | <P>
| + | |
| − | If you have field names that are substrings of other field names (e.g., col1
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| − | and col10) you should
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| − | indicate so, by surrounding the field name (and the % character) with square
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| − | brackets (e.g., [%col10]). This will prevent the %col10 field
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| − | name being mistaken for the %col1 field name with a 0
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| − | on the end. The brackets will be removed by QGIS when it substitutes in the
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| − | value of the field. If you want the substituted field to be surrounded by square
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| − | brackets, use a second set like this: [[%col10]].
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| − | | + | |
| − | <P>
| + | |
| − | The Identify Results dialog box includes a <EM>(Derived)</EM> item that
| + | |
| − | contains information relevant to the layer type. The
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| − | values in this item can be accessed in a similar way to the other fields
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| − | by using preceeding the derived field name by (Derived).. For
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| − | example, a point layer has an X and Y field and the
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| − | value of these can be used in the action with %(Derived).X and
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| − | %(Derived).Y. The derived attributes are only available from the
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| − | Identify Results dialog box, not the Attribute Table dialog box.
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| − | | + | |
| − | <P>
| + | |
| − | Two example actions are shown below:<A NAME="431"></A>
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| − | | + | |
| − | <P>
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| − | | + | |
| − | <UL>
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| − | <LI>konqueror http://www.google.com/search?q=%nam
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| − | </LI>
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| − | <LI>konqueror http://www.google.com/search?q=%%
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| − | </LI>
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| − | </UL>
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| − | | + | |
| − | <P>
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| − | In the first example, the web browser konqueror is invoked and passed a URL to
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| − | open. The URL performs a Google search on the value of the nam field
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| − | from our vector layer. Note that the application or script called by the
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| − | action must be in the path or you must provided the full path. To be sure, we could
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| − | rewrite the first example as: /opt/kde3/bin/konqueror
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| − | http://www.google.com/search?q=%nam. This will ensure that the konqueror
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| − | application will be executed when the action is invoked.
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| − | | + | |
| − | <P>
| + | |
| − | The second example uses the %% notation which does not rely on a particular
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| − | field for its value. When the action is invoked, the %% will be replaced by
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| − | the value of the selected field in the identify results or attribute table.
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| − | | + | |
| − | <P>
| + | |
| − | Using Actions<A NAME="439"></A><A NAME="label_usingactions"></A>Actions can be invoked from either the Identify Results dialog or an
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| − | Attribute Table dialog.
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| − | (Recall that these dialogs can be opened by clicking | + | |
| − | mActionOpenTableIdentify Features
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| − | or
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| − | mActionOpenTableOpen Table.)
| + | |
| − | To invoke an action,
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| − | right click on the
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| − | record and choose the action from the popup menu. Actions are listed in the popup
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| − | menu by the name you assigned when defining the actions. Click on the action you
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| − | wish to invoke.
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| − | | + | |
| − | <P>
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| − | If you are invoking an action that uses the %% notation, right-click on the
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| − | field value in the Identify Results dialog or the
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| − | Attribute Table dialog that you wish to pass to the application or script.
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| − | | + | |
| − | <P>
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| − | Here is another example that pulls data out of a vector layer and inserts them
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| − | into a file using bash and the echo command (so it will only work
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| − | or perhaps ). The layer in question has fields for a species name
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| − | taxon_name, latitude lat and longitude
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| − | long. I would like to be able to
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| − | make a spatial selection of a localities and export these field values to a
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| − | text file for the selected record (shown in yellow in the QGIS map area). Here is
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| − | the action to achieve this:
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| − | | + | |
| − | <P>
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| − | <PRE>
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| − | bash -c "echo \"%taxon_name %lat %long\" >> /tmp/species_localities.txt"
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| − | </PRE>
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| − | | + | |
| − | <P>
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| − | After selecting a few localities and running the action on each one, opening
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| − | the output file will show something like this:
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| − | | + | |
| − | <P>
| + | |
| − | <PRE>
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| − | Acacia mearnsii -34.0800000000 150.0800000000
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| − | Acacia mearnsii -34.9000000000 150.1200000000
| + | |
| − | Acacia mearnsii -35.2200000000 149.9300000000
| + | |
| − | Acacia mearnsii -32.2700000000 150.4100000000
| + | |
| − | </PRE>
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| − | | + | |
| − | <P>
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| − | As an exercise we create an action that does a Google search on the
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| − | lakes layer. First we need to determine the URL needed to perform a search on a
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| − | keyword. This is easily done by just going to Google and doing a simple
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| − | search, then grabbing the URL from the address bar in your browser. From this
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| − | little effort we see that the format is: <TT><A NAME="tex2html72"
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| − | HREF="http://google.com/search?q=qgis">http://google.com/search?q=qgis</A></TT>,
| + | |
| − | where qgis is the search term. Armed with this information, we can
| + | |
| − | proceed:
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| − | | + | |
| − | <P>
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| − | | + | |
| − | <OL>
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| − | <LI>Make sure the lakes layer is loaded.
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| − | </LI>
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| − | <LI>Open the Layer Properties dialog by double-clicking on the layer in the
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| − | legend or right-click and choose Properties from the popup menu.
| + | |
| − | </LI>
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| − | <LI>Click on the Actions tab.
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| − | </LI>
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| − | <LI>Enter a name for the action, for example Google Search.
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| − | </LI>
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| − | <LI>For the action, we need to provide the name of the external program to
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| − | run. In this case, we can use Firefox. If the program is not in
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| − | your path, you need to provide the full path.
| + | |
| − | </LI>
| + | |
| − | <LI>Following the name of the external application, add the URL used for
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| − | doing a Google search, up to but not included the search term:
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| − | <TT><A NAME="tex2html73"
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| − | HREF="http://google.com/search?q=">http://google.com/search?q=</A></TT>
| + | |
| − | </LI>
| + | |
| − | <LI>The text in the Action field should now look like this:
| + | |
| − | <BR>
| + | |
| − | firefox <TT><A NAME="tex2html74"
| + | |
| − | HREF="http://google.com/search?q=">http://google.com/search?q=</A></TT>
| + | |
| − | </LI>
| + | |
| − | <LI>Click on the drop-down box containing the field names for the
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| − | lakes layer. It's located just to the left of the
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| − | Insert Field button.
| + | |
| − | </LI>
| + | |
| − | <LI>From the drop-down box, select NAMES and click Insert Field.
| + | |
| − | </LI>
| + | |
| − | <LI>Your action text now looks like this:
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| − | <BR>
| + | |
| − | firefox
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| − | <TT><A NAME="tex2html75"
| + | |
| − | HREF="http://google.com/search?q=%NAMES">http://google.com/search?q=%NAMES</A></TT>
| + | |
| − | </LI>
| + | |
| − | <LI>Fo finalize the action click the Insert action button.
| + | |
| − | </LI>
| + | |
| − | </OL>
| + | |
| − | | + | |
| − | <P>
| + | |
| − | This completes the action and it is ready to use. The final text of the action
| + | |
| − | should look like this:
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| − | | + | |
| − | <P>
| + | |
| − | <DIV ALIGN="CENTER">
| + | |
| − | firefox <TT><A NAME="tex2html76"
| + | |
| − | HREF="http://google.com/search?q=%NAMES">http://google.com/search?q=%NAMES</A></TT>
| + | |
| − | | + | |
| − | </DIV>
| + | |
| − | | + | |
| − | <P>
| + | |
| − | We can now use the action. Close the Layer Properties dialog and zoom in to an area
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| − | of interest. Make sure the lakes layer is active and identify a
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| − | lake. In the result box you'll now see that our action is visible:
| + | |
| − | | + | |
| − | <P>
| + | |
| − | | + | |
| − | <DIV ALIGN="CENTER"><A NAME="fig:identify_action"></A><A NAME="484"></A>
| + | |
| − | <TABLE>
| + | |
| − | <CAPTION ALIGN="BOTTOM"><STRONG>Figure:</STRONG>
| + | |
| − | Select feature and choose action </CAPTION>
| + | |
| − | <TR><TD>
| + | |
| − | <DIV ALIGN="CENTER">
| + | |
| − | </DIV>
| + | |
| − | <P></P>
| + | |
| − | <DIV ALIGN="CENTER"> [clip=true, width=8cm]action_identifyaction
| + | |
| − | | + | |
| − | </DIV></TD></TR>
| + | |
| − | </TABLE>
| + | |
| − | </DIV>
| + | |
| − | | + | |
| − | <P>
| + | |
| − | When we click on the action, it brings up Firefox and navigates to the URL http://www.google.com/search?q=Tustumena . It is also possible to add further
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| − | attribute fields to the action. Therefore you can add a ``+'' to the end of the action
| + | |
| − | text, select another field and click on Insert Field. In this example there
| + | |
| − | is just no other field available that would make sense to search for.
| + | |
| − | | + | |
| − | <P>
| + | |
| − | You can define multiple actions for a layer and each will show up in the
| + | |
| − | Identify Results dialog. You can also invoke actions from the attribute table
| + | |
| − | by selecting a row and right-clicking, then choosing the action from the popup
| + | |
| − | menu.
| + | |
| − | | + | |
| − | <P>
| + | |
| − | You can think of all kinds of uses for actions. For example, if you have a point layer
| + | |
| − | containing locations of images or photos along with a file name, you could
| + | |
| − | create an action to launch a viewer to display the image. You could also use
| + | |
| − | actions to launch web-based reports for an attribute field or combination of
| + | |
| − | fields, specifying them in the same way we did in our Google search example.
| + | |
