WKT / GeoJSON from data

If you have a data source with geospatial data, such as SQL Server, PostgreSQL or Snowflake, then makes sense to load this data directly into your report via the Power BI semantic model. Icon Map Pro supports data in Well Known Text (WKT) and GeoJSON loaded from a field in your data.

Data setup

In order to display Well Known Text (WKT) or GeoJSON data from the Power BI data model, the following fields must be provided:

• ID - a unique Id representing that object
• Image / WKT / GeoJSON - the field or Measure containing your shape data. You may need to set the Aggregation type to "First" if your data is not coming from a measure.

Sample data

ID	Longitude	Latitude	Destination Longitude	Destination Latitude	Circle Size	Cluster Group	H3 Weight	Heatmap Weight	Image / WKT / GeoJSON	Feature Reference	Feature Weight
WKT1	null	null	null	null	null	null	null	null	POLYGON((30 10, 40 40, 20 40, 10 20, 30 10))	null	null
GeoJSON1	null	null	null	null	null	null	null	null	{ "type": "Feature", "geometry": { "type": "LineString","coordinates": [[102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]] }}	null	null

Configuration Options

You will need to enable the "WKT / GeoJSON (from data)" toggle in the Data Layers formatting settings. Icon Map Pro will check to see if your data is an image or shape data and apply the appropriate settings.

Include in Auto Zoom

Whether the shape should be included in the auto zoom of the map. Can be set to yes or no using conditional formatting to apply to specific shapes.

Include Tooltip

Whether to include a tooltip. Can be set to yes or no using conditional formatting to apply to specific shapes.

Selectable

Whether the shape can be clicked on for interaction with other visuals. Can be set to yes or no using conditional formatting to apply to specific shapes.

Point Size

If your WKT or GeoJSON shape relates to a point, then this field allows you to configure its size in pixels.

Image at the start / end of a linestring

If your shape is a linestring, then you can position an image at the start or end of the line, without having to add an additional row of data. This can be useful for drawing the history of vehicles, then drawing the current location of the vehicle.

The following settings are available to format the image:

Image URL at linestring start / end

The URL of the image. This can be hardcoded so that all lines display the same image, or use a DAX expression or field value for different images at each linestring end. URLs should start https or data. The same rules should be followed as other map images.

Image Rotation

This should represent a number between 0 and 359 and represents the number of degrees to rotate the image. This can be hardcoded, or set using conditional formatting from a DAX measure or field value.

Image Width and Height

These settings allow you to set the size of the image and represent the width and height in pixels. This can be hardcoded, or set using conditional formatting from a DAX measure or field value.

EPSG (Coordinate Reference System)

Allows you to specify a specific reference system for your coordinates. The default used is EPSG:4326 / WGS84 and expects longitude and latitude coordinates. You can use other coordinate systems by specifying the relevant EPSG number. For example, to use British National Grid coordinates, enter 27700. Other EPSG codes can be found here.

Minimum & Maximum Zoom

The zoom levels between which the layer should be shown.

Formatting

The following options are available for WKT / GeoJSON shapes:

Outline color

The color of shape outlines or linestrings.

Outline transparency

Transparency shape outlines or linestrings. This should be a numeric value between 0 and 100.

Outline Width

Width of the outline in pixels. Can be a decimal number.

Dash Array

The dash array determines the pattern used for the line. It consists of a series of space separated numbers. Each value represents the length along the line that should be painted (the dash) and then not painted (the gap). Eg:

4 4

Dash Animation Speed

If a dash array is used to draw a line pattern, it can be animated to show the direction of travel. The speed can be a negative or positive number, such as 10.

Fill Color

Fill color of a shape.

Fill Transparency

Transparency of the fill of a shape.

Fill Style

Whether the shape is solid or hatched.

When hatched is selected, the following additional options are available:

Hatch Angle

The angle of the lines forming the hatched fill.

Hatched Width

The width of the lines forming the hatched fill.

Line Symbols

It is possible to add a symbol along the path of a LineString or MultiLineString.

Include Line Symbol

Determines whether symbols are displayed. Can be set using conditional formatting values "yes" or "no" to determine the setting for each individual line.

Line Symbol Text

The text/symbol that is drawn along the line. Use Unicode Characters to draw symbols such as planes, arrows etc. Symbols should face towards the right to show in the direction of the line. Use spaces to determine the gaps between. This setting can be determined using conditional formatting to show different text or a different symbol for each line.

Line Symbol Color

Set the color of the symbol or text.

Line Symbol Size

Set the size of the symbol/text in pixels

Line Symbol Orientation

This determines how the symbols are drawn:

• Normal - oriented along the direction of the line
• Flipped - rotated by 180 degrees
• Perpendicular - rotated by 90 degrees

Line Symbol Offset

Ensure your symbols are aligned to the center of the line, or offset below or above. This value can be a negative number to draw text above the line.

Line Symbol Repeat

Determines whether one symbol is shown, or multiple. Can be set using conditional formatting using the values "yes" or "no".

Dealing with Power BI's column width limits

When loading data into a Power BI semantic model there are limits on the maximum number of characters that can be loaded. Text fields in Power BI are limited to 32764 characters. Often WKT or GeoJSON shapes can be truncated, and therefore not display in your map. There are a number of strategies that you can take to reduce the size of your shapes:

• Reduce the decimal precision of your shapes. Often you don't need to store longitude and latitude coordinates within your shapes with large numbers of decimal places. Reducing these can cause a significant reduction in the number of characters. PostgreSQL has a built-in function for performing this, ST_ReducePrecision.

• Reduce the number of points in your polygons and linestrings. Tools such as QGIS have inbuilt capabilities if working with shape files, or if using databases such as SQL Server or PostgreSQL, then you could consider the inbuilt spatial functions such as: ST_Simplify or ST_SimplifyPreserveTopology with PostgreSQL, or Reduce with Microsoft SQL Server.

If your shapes are still too large, then splitting the shapes into multiple rows or columns and then creating a DAX measure to combine them back together will work for shapes up to around a million characters.

Caution when using Direct Lake or Microsoft Fabric's Data Warehouse

Whilst PowerQuery and Power BI support up to 32764 characters in a column, this limit is severely reduced in Microsoft Fabric's Synapse Data Warehouse with support for only 8000 characters. WKT or GeoJSON data will need to be split before being stored in the data warehouse.

This 8000 character is also a limit, even if you are not using the Data Warehouse, and instead have Semantic Models using Microsoft Fabric's Direct Lake mode to connect to your data. Whilst Direct Lake supports 32764 characters, if your connection falls back to DirectQuery, then your data will be truncated to 8000 characters as it then uses the SQL endpoint. To mitigate this, you will need to split your shapes at 8000 characters, not 32764.

Generating linestrings from multiple rows of point data

If you have a series of longitude and latitude points on multiple rows, it is possible to concatenate these into a single linestring using DAX. This is useful if you have a series of vehicle locations over time and want to create a single track on the map for that vehicle, perhaps adding an image for the vehicle at its latest location.

Based on the following table of data representing the tracks of two vehicles:

vehicleID	longitude	latitude	timestamp
vehicle 1	-0.93	51.34	2025-05-29T10:10
vehicle 1	-0.94	51.34	2025-05-29T10:12
vehicle 1	-0.94	51.35	2025-05-29T10:13
vehicle 2	-0.81	52.01	2025-05-29T10:09
vehicle 3	-0.84	52.00	2025-05-29T10:11

and the following DAX measure:

VehicleTrack = 
    "LINESTRING ("
        & CALCULATE (
            CONCATENATEX (
                'TableName',
                'TableName'[longitude] & " " & 'TableName'[latitude],
                ",",
                'TableName'[timestamp], DESC
            ) & ")"
        )

Adding the vehicleID field to Icon Map Pro's ID field well, and the new VehicleTrack measure to the Image / WKT / GeoJSON field well, will result in the following WKT being generated:

vehicleID	VehicleTrack
vehicle 1	LINESTRING (-0.93 51.34,-0.94 51.34,-0.94 51.35)
vehicle 2	LINESTRING (-0.81 52.01,-0.84 52.00)

DirectQuery and Composite Models for large geospatial datasets

If you have a large number of geospatial data, it may become impractical to import it into your Power BI dataset. You could consider setting a DirectQuery connection for the table holding your spatial data. In that way it requested only when it is needed to display on the map.

To maintain performance with the rest of your report, you could consider a composite model where your spatial data table is in Direct Query mode and the rest of the semantic model is in import mode.