Combine several layers in one map

One Icon Map Pro visual can draw several data layers at once, for example stores as circles, deliveries as lines and sales regions as shapes. All of them come from one table. This page explains how each row finds its layer, how to build that table, and what to check when a layer draws nothing.

The rule

A row is drawn by the layer whose fields it fills in.

There is one set of field wells, and every data layer reads it. The visual looks at each row and asks which fields have a value:

• A row with a longitude, a latitude and a circle size is a circle.
• A row with a longitude, a latitude and a destination is a line.
• A row with only a feature reference is a shape from a file.

Two more things must be true for a row to be drawn:

1. The fields of other layers are empty on that row. A store row that also has a destination is no longer a circle. It is treated as a line.
2. The layer is turned on. A row that fits a layer which is turned off is not drawn.

So to show several layer types on one map, keep them in one table, give each row only the fields for its own layer, and leave the others empty.

Empty and blank

A field is empty on a row when:

• It is null in the data, or a measure returns BLANK().
• It is a text value with nothing in it, or only spaces. Tables that come from CSV files, Excel or Power Query often hold empty text instead of null. Icon Map Pro treats both the same way.
• No field has been added to that field well at all.

Zero is a value, not blank. A row with a Circle Size of 0 still has a circle size.

What each layer needs

Every layer needs ID. "Cell Weight" in this table is the Cell (H3/S2/A5/Geohash) Weight field well, and "Destination" means both Destination Longitude and Destination Latitude.

Points worth knowing:

• Tooltips, Cluster Group, Feature Weight and Daylight Date & Time never decide which layer a row goes to. Fill them in on any row.
• Lines with circles. A line row may have a Circle Size. With Include circle(s) at: set in the Lines settings, circles are drawn at the ends of the line.
• Circle or column. A row with both a Circle Size and a Column Height is neither. Fill in one of them.
• Images and shapes share a field well. A row with an image and coordinates is an image. A row with WKT or GeoJSON text and no coordinates is a shape.
• Feature Reference is shared. Shapes from files, vector tiles, catalog layers and ArcGIS layers all join on Feature Reference. A row with a feature reference is offered to each of these layers that is turned on, so the same row can color a boundary in more than one of them.

A worked example: stores and deliveries

You want stores as circles sized by sales, and deliveries as lines from a depot to each store. The table needs one row for each store and one row for each delivery:

• The store rows fill in the coordinates and Size, and leave the destination empty. Circles draws them.
• The delivery rows fill in the coordinates and the destination, and leave Size empty. Lines draws them.

Add the fields to the visual, each column to the field well of the same name, with Size in Circle Size. Then turn on both layers.

In the Layer Manager, select Add a layer, then Data layer. The tiles for Circles and Lines & flows show Fields ready, with the number of rows each would draw. Add them both, then select Apply changes.

To add sales regions as a third layer, add a row for each region that fills in only the feature reference, and add that column to Feature Reference:

Then turn on Shapes from files and add the file of regions.

Build the table

In most models the stores, deliveries and regions are separate tables. Power BI needs them as one table for the visual, so combine them. Give every row a unique ID: if a store and a delivery could share an ID, add a prefix.

Power Query: append the tables

Give the columns the same names in each query, then use Append Queries as New. Columns that a query does not have are filled with null, which is what the map needs.

let
    StoreRows = Table.SelectColumns(Stores, {"ID", "Type", "Longitude", "Latitude", "Size"}),
    DeliveryRows = Table.SelectColumns(
        Deliveries,
        {"ID", "Type", "Longitude", "Latitude", "Destination Longitude", "Destination Latitude"}
    ),
    MapItems = Table.Combine({StoreRows, DeliveryRows})
in
    MapItems

DAX: a calculated table with UNION

UNION stacks tables whose columns are in the same order. Use BLANK() for the columns a row type does not use.

Map Items =
UNION (
    SELECTCOLUMNS (
        Stores,
        "ID", "Store " & Stores[Name],
        "Type", "Store",
        "Longitude", Stores[Longitude],
        "Latitude", Stores[Latitude],
        "Destination Longitude", BLANK (),
        "Destination Latitude", BLANK (),
        "Size", Stores[Sales]
    ),
    SELECTCOLUMNS (
        Deliveries,
        "ID", "Delivery " & Deliveries[Delivery No],
        "Type", "Delivery",
        "Longitude", Deliveries[Depot Longitude],
        "Latitude", Deliveries[Depot Latitude],
        "Destination Longitude", Deliveries[Store Longitude],
        "Destination Latitude", Deliveries[Store Latitude],
        "Size", BLANK ()
    )
)

Measures that are blank for other rows

When the value for a field well comes from a column that has a value on every row, wrap it in a measure that returns blank for the rows of other layers. IF with no third argument returns BLANK():

Store Size =
IF (
    SELECTEDVALUE ( 'Map Items'[Type] ) = "Store",
    SUM ( 'Map Items'[Sales] )
)

Put the measure in Circle Size in place of the column. Store rows get a size and are drawn as circles. Delivery rows get a blank and are drawn as lines. The same pattern works for any field well, for example a destination that is blank unless the row is a delivery:

Delivery Destination Longitude =
IF (
    SELECTEDVALUE ( 'Map Items'[Type] ) = "Delivery",
    AVERAGE ( 'Map Items'[Destination Longitude] )
)

Choose layers with a slicer

Because the layer follows the data, a slicer can turn layers on and off for report users. Add a slicer on the Type column of the example table. Selecting Store shows only the circles, and selecting Delivery shows only the lines, because the other rows are filtered out before they reach the map.

Check what each layer draws

The Layer Manager shows how your rows were shared out. Open it from Format pane > Layer Manager > Open Layer Manager.

• The Your data panel lists the fields you have added and says whether every row is drawn, for example "Every row is drawn: Circles, Lines & flows." or "12 of 240 rows reach no layer."
• A layer that is turned on but draws nothing has a warning on its row. Select See why to see example rows, the field that sends them elsewhere, and how to fix it.
• When two layers compete for the same rows, the explanation includes a ready-made DAX measure, written with your own table and column names, that is blank on the rows of one layer. Select Copy, create a new measure from it, and use it in place of the field.

See Check your data.

When no row reaches any turned-on layer while you are editing, the map shows the "What kind of map are you making?" guide. It lists each layer type with the fields it needs and marks the ones your fields already fit. See Choose a layer type.

Common mistakes

Tips and limits

• The drawing order of the layers is set by each layer's Z Index. See Data layers overview.
• All layers share the visual's row limit. See Data rows and limits.
• A map that needs context rather than data, such as a boundary outline or a weather layer, does not need rows at all. Use a reference layer.

Related

• How Icon Map Pro works
• Fields reference
• Choose a layer type
• Troubleshooting