When using vector layers it might be useful to work with a subset of features. About that, MapStore let the user set up a Layer Filter that acts directly on a layer with WFS available and filter its content upfront. The map will immediately update when a filter is applied.
The MapStore's filtering capabilities are working on top of the WFS specifications so that service must be enabled if you want to filter a layer using the tools described in this section.
In MapStore it is possible to apply filters on layers in three different ways:
With the Layer Filter tool available in TOC
With the Advanced Search tool available from the Attribute Table
With the Quick Filter available in the Attribute Table
This filter is applicable from the Filter layer button in TOC's Layers Toolbar and it will persist in the following situations:
- Using other tools like the Identify tool:
- Applying another type of filter
- Opening the map next time (you need to Save the map from the Side Toolbar after applying a filter)
Once a Layer filter is set, it is possible to enable/disable it simply by clicking on the button that will appear near the layer name in TOC:
This filter is applied through the Query Panel. Once the settings are chosen, it is possible to Apply them. After that the user can:
Undo the last changes
Reset the filter to the initial situation
Save the filter in order to make it persistent
This filter, applicable from Advanced Search button in Attribute Table, behaves as follows:
- It can be used to apply a filter to a layer for search purposes in Attribute Table: this filter is applied in
ANDto the Layer Filter if it is already been set.
- It is possible to sync this filter with the map through the icon:
- It will be automatically removed/reapplied by closing/opening the Attribute Table
Also this filter is applied through the Query Panel but in this case it is not possible to Save it and make it persistent reopening the map the next time. The user is only allowed to apply it by clicking on Search or eventually Reset it.
The user can perform three type of quick filters:
Filter by attributes
Filter by clicked point in the map
Filter by viewport
Quick Filter by attributes
This filter is available for each colum in the Attribute Table just below the field names and it can be also used in combination with other filter applied:
The user has the possibility to apply simple filters by attributes simply typing the filter's value in the available input fields (Date or Time pickers are available according to real attributes data types and a tooltip usually gives an information on how to fill the filter's input field). Filtering by one or more attributes, layer records in Attribute Table are automatically filtered accordingly.
If the user wants to filter by an attribute of type String, he can simply write something inside the input box and the list of records in table will be automatically filtered by matching with the input text.
If the User wants to filter by a numeric attribute, he can type directly a number or an expression using the following operators:
Not equal (!= or !== or <>)
Equal or less than (<=)
Equal or greater than (>=)
Less than (<)
Greater than (>)
Equal (=== or == or =)
In order to filter a numerical filed matching the records greater than or equal to a certain threshold value, an example can be:
Quick Filter by map interaction
It is possible to filter records in the Attribute Table by clicking on the map or doing a selection directly in a map of multiple features. The user can activate the Filter on the map button (once clicked the button turns blue) and then:
Click on the map over the features he wants to select
Add multiple features to the selection by pressing Ctrl and clicking again over other features in map
- Add multiple features to the selection by pressing Ctrl + Alt and drawing a selection box in map
The list of records in the Attribute Table will be automatically filtered according to such user selection and then the user can disable the geometry filter through the Remove filter button.
Quick Filter by viewport
From the Attribute Table the user can filter data by map viewport through the Filter by viewport button. Once clicked, the toggle button turns its state to green and the list of records in the Attribute Table is filtered by showing only records corresponding to layer features present in the current map viewport.
The list of records in the Attribute Table is automatically updated when the user pan/zoom the map view. It is possible to deactivate the Filter by viewport by clicking again the same toggle button.
The Quick Filter remains active as long as the Attribute Table is open but, unlike the Advanced Search, closing the Attribute Table it will not reappear anymore if the Attribute Table is re-opened in a second time.
This tool is used to define advanced filters in MapStore. It includes three main sections:
Region of Interest
This filter allows to set one or more conditions referred to the Attribute Table fields.
First of all it is possible to choose if the filter will match:
After that, the user can insert one or more conditions, that can also be grouped in one or more condition groups (use the button in order to create a group).
A condition can be set by selecting a value for each of the three input boxes:
The first input box allows to choose a layer field
In the second input box it is possible to choose the operation to perform (selecting a text field can be =, like, ilike or isNull, selecting a numerical field, can be =, >, <, >=, <=, <> or ><)
The third input box (in case of fields of type String) provides a paginated list of available field values already present in the layer's dataset (a GeoServer WPS process is used for this). In case of numeric fields the user can simply type a value to use for the filter.
the "paginated list of available field values" above is available only if the server provides the WPS process
A simple Attribute Filter applied for a numerical field can be, for example:
Region of interest
In order to set this filter the user can:
Select the Filter type by choosing between Viewport, Rectangle, Circle, Polygon (selecting Rectangle, Circle or Polygon it is necessary to draw the filter's geometry on the map)
Select the Geometric operation by choosing between Intersects, Is contained, Contains
Applying a Circle filter with Intersect operation, for example, the process could be similar to the following:
Once this filter is set, it is always possible to edit the coordinates and the dimensions of the drawn filter's geometry by clicking on the Details button . Editing a circle, for example, it is possible to change the center coordinates (x, y) and the radius dimension (m):
This tool allows to set cross-layer filters for a layer by using another layer or even the same one.
This filter tool requires the Query Layer plugin installed in GeoServer
In order to set up a cross-layer filter the options below are required:
Target layer (between those present in the TOC)
Operation to be chosen between Intersects, Is contained or Contains
Optionally some Conditions (see Attribute filter)
In order to better understand this type of filter, let's make an example. We suppose that the user want to filter the Italian Regions with the Unesco Item's one:
In particular, if our goal is to take a look at the Italian Regions that contain the Unesco sites with serial code=1, the operations to perform can be the following: