A Dynamic Station Group query is used to group stations that meet specific conditions. The station groups that are created this way are called "Dynamic" because the stations in the group may change as data is added/edited in the database. Alternatively, the Stations Groups that are user defined are referred to as "Static" because they do not change unless the user makes the changes manually. Station Groups are used throughout Hydro GeoAnalyst including as source data for Well Profiles, Cross Sections, 3D Scenes, and more.
The following provides an example of creating a Dynamic Station Group Query with guided steps using the Demo Project.
If the Query Builder tab is not yet opened, select the Query Builder icon from the main toolbar.
In the Query Builder tab toolbar, select the New button and the New Query dialog will appear.
•The default Query Type is the General Query - we need to change this by selecting the Dynamic Station Group option.
•Provide a Query Name: Station with TOC exceeding 320masl (for this example).
•Select OK to create the query.
|You will notice that the Display Fields and the Group Conditions sections have become disabled - these are not available for Dynamic Station Group Queries.
•Click once on the TOC field (it will become highlighted blue), and drag this field into the blank Conditions field (under the Expression column). The TOC field will be added to the Query Conditions. (Alternately, you may use the button (on the bottom half of the conditions section) to add conditions, then define them manually).
•We need to set an operator and value for our Condition. You will notice there are several options in the Operator drop down list (>, >=, <, <=, =, <>, IS, IS NOT, and LIKE) providing you several options to query your data from the database.
•Select the > option from the drop down list in the Operator column.
•Enter the number 320 in the Value field.
In the Conditions section, select the Source Conditions. The options are Project, Station Group, and Database. If Station Group is selected, then another combo box will become activated where you can select the appropriate Station Group to be the source for this query. If Project is selected, then all stations in the project will be queried. If Database is selected, then the query will be applied to the entire database and span all projects stored within that database (if applicable). For this example, we will use the default which is Project.
The Query Builder should look similar to the image below:
•If you need, you can add multiple conditions - these need to be linked by specifying an additional Operator (the far right column in the Conditions window); choose from AND, OR. For this example we will only use one condition.
•Select the Execute Query button and you will be moved to the Data Query tab to see the results of your query. The results of a Dynamic Station Group query will have only 2 columns - the RowID and the Station ID.
More useful is the fact that the new query will now appear as a new branch under the Station Group branch in the Project Tree and is available for use with other modules.
The Dynamic Station Group queries can be distinguished from a user-defined station group (static) by the color of the icon used to display in the Project Tree. Blue icons are Static Station Groups while green icons are Dynamic Station groups.