All of the operations that LAS knows how to perform are defined in the operationsV7.xml file. For example:
<operation ID="MY_2D_PLOT" default="true" name="Special Map" output_template="zoom"
service_action="MY_Plot_2D_XY" order="0001" category="visualization" isZoomable="true">
<result type="image" ID="plot_image" streamable="true"
mime_type="image/gif" file_suffix=".gif" />
<result type="image" ID="ref_map" file_suffix=".gif" />
<result type="map_scale" ID="map_scale" file_suffix=".xml"/>
<result type="debug" ID="debug" file_suffix=".txt"/>
<result type="cancel" ID="cancel" file_suffix=".txt"/>
<intervals name="xy" type="Maps" title="Custom Latitude-Longitude Plot"/>
<grid_type name="regular" />
So, you'll need a definition of your operation. It must define a human readable name, and a unique ID. The operation should also define a collection of expected results, you have to define a least one result.
This operation defines a whole bunch of expected results (an image file, a reference map, a file with map scale information, debug text and a potential cancel result to prep the backend service for canceling the running job). Don't define the map_scale result unless your Ferret script is prepared to make the map scale output. For simplicity, let's assume you'll make an image, want stdout and stderr collected and returned as debug information and you want to be able to cancel a job. When this operation is run, the system will look for a Ferret script called MY_Plot_2D_XY in the collection of scripts deployed with the server. The details of how to create the script are in the next section. The results of the the plot will be rendered by an output template named in the template attribute.
The user interface organizes visualization operations according to the dimensions of the data set that appear in the plot. Sometimes an operation can work with many different "views" of the data set. Those dimensions which are plotted as an interval (not as a fixed point) in the plot are defined by the <inteverals> elements in the plot operation. This one only uses one (the XY or latitude-longitude view). Since this operation is in the visualization category (category="visualization") and is one of the default operations (default="true") it will appear in the left-hand navigation section of the UI called "Maps" with the title "Custom Latitude-Longitude Plot".