Flows - Tasks - Align Polygons

The Align Polygons task enables you to align polygon geometries from one layer to geometries from another layer. It has been designed to help in cleaning planning application data and aligning the outlines of planning records with OS Topography Layer i.e.: Master Map.

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Align Polygons works by casting the geometry from the Layer onto the Stencil Layer and approximating which collection of polygons from the Stencil Layer closest represent the source geometry.

Open

Task Configuration

The configuration of this task, just like any other eVO Task, is preserved within a map. This task utilises layers contained within the map. This means that before setting up the task, you should prepare a map. Please see below the list of elements which have to be present within the map.

1. Layer - this is the layer which contains incorrect geometries. In most cases this layer stores planning application data. Data in this layer will be cleansed.

2. Stencil Layer - this is the source of correct geometries. In most cases it means the MasterMap Topography Area layer.

3. Auxiliary Layer - this is the auxiliary layer which stores approximated polygons. This layer must comprise of at least 3 columns: Primary Key, Geometry and a text field allowing for at least 2000 characters to be written. An example of Auxiliary Layer is shown below.

4. Offset Layer (optional) - this is the PAI offsets layer. This data is pre-processed by StatMap and delivered to the customer upon request free of charge.

When configuring the task you need to create an empty Flow and add the Align Polygons task to the Flow’s plan space (see Setting up a Flow and Adding Task to Flow for general information on creating Flows and managing Tasks). Assuming that you have all required layers available in your map, setting up the Align Polygons task is a very simple task. You need to provide each parameter by selecting a layer name or a field name from the drop down lists.

The only parameter which you need to enter manually, although it is by default set to 90%, is the Minimum Stencil Area Ratio. This parameter is responsible for deciding whether a polygon from the stencil layer will be included in the collection or not. If Stencil Layer polygon’s area contained within the checked polygon geometry is higher than this parameter, it will be included. If it’s lower, the Stencil Layer polygon will not be added to the collection. In most scenarios the default value of 90% delivers the best results.

Task usage

Once the task has been configured and saved in the map, it can be accessed via the Flows pane.

When you click the name of the flow which interest you, an actions pane, just like the one shown below, will open.

If you’re only just starting your work with particular flow, first thing you need to do is press Recalculate so that the engine can analyse all records and generate suggestions as to the changes to geometries necessary to align them with the Stencil Layer. Recalculate can take time depending on the number of records in the source layer, to complete its action but it is only necessary to do it once per layer as the suggestions are preserved in the AUX layer.

There are three action buttons (Recalculate, Apply and Refresh) and list filtering buttons below these.

Actions

Recalculate - as mentioned earlier it is generally used just once per layer at the beginning. It is however possible to use it again due to the refresh of the stencil layer data or changes to the Filter Query applied on the Source Layer via Layer Properties. In these scenarios, the recalculate will generate new suggestions for all records, which do not have the Accepted, Kept, To be fixed or Edited flag assigned.

Apply - this action copies geometries from the AUX layer to the Source Layer. It does so for all records, which have Accepted flag assigned.

Refresh - this button refreshes the list of records. It is useful if more than one person works on the same flow.

Filters

All - by default, the list shows all records which have been successfully processed during last Recalculate execution.

Accepted - As the name suggest, this filter will show all records which have been accepted. These records will be copied from the AUX layer to the Source Layer if Apply is executed.

Kept - These are the records, which have been deemed correct and not require any modifications.

To be fixed - Shows all records which have been deemed incorrect and will be corrected later or by someone else.

Edited - Displays those records, for which the suggested geometry required manual changes. The changes have been fully or partially finished but the finished geometry has not yet been reviewed and accepted.

Outstanding - This filterer shows all records, which have no flag assigned.

Active record pane

When you click on a record in the list, you will see that there are multiple buttons shown.

First row:

• Primary key of the record in the Source Layer

• Login of the user, who has this particular record activated. This information is useful when there are multiple people accessing the same flow.

• Penalty score of the record i.e.: how much the source record is different from the suggested record. The lower the score the better. Score of 0 means almost perfect alignment while score of 999 means that there was no geometry in the stencil layer which could be traced to resemble the source record.

An example of record with minimum penalty score

An example of record with maximum penalty score

An example of a record with an average penalty score

Second row:

• Accept Aligned - Sets the record’s flag to Accepted and prepares it to be processed when Apply is executed.

• Keep Original - Sets the record's flag to Kept. The record is correct as is. No action is necessary when Apply is executed.

• To Be Fixed - Sets the flag on the record to To be fixed. In a multi user / various competency scenario, this can be a signal for more competent editors that they should amend the record.

Third row:

• Edit - This button will begin editing session of the currently focused record. Users should use any editing tools from the Edit tab, which are available to them. If a user starts the editing session and makes any changes to the suggested geometry, the record will have the Edited flag assigned.

• Reset - Press this button to remove any assigned flag.

Setting up a Flow

1. Open a map

2. Go to Flows tab

3. Click New button above the list of existing flows to add a New Flow to the list

4. Double click the New Flow entry or highlight it on the list and click Properties button to see the flow’s properties. On this window you can change the Name of the flow, add a Tag to the flow or change its Description.

Adding Task to Flow

Once you have the Flow container, scroll through the Tasks section of the pane. When you see the task which you want to add, highlight it and click Add. When you do it, the task icon will show in the flow's plan area.

To begin task configuration, please double click the aforementioned icon.