A KML Layer renders a KML (Keyhole Markup Language) or KMZ (compressed KML) file on the map. The file name is specified by the KmlFileName property on the layer. The file may be loaded from a URL, from a local disk file, or embedded in the report. If the file is not embedded (EmbedKmlFile is False), and the directory is not specified, the file is loaded from the directory containing the report definition.

• KML item expressions: when a KML layer is rendered, items present in the KML file are processed in sequence. As each item is loaded, several expressions specified on the layer are evaluated allowing to control the process - for example, only load certain items based on various criteria, or modify items' visual attributes. Additionally, if a RecordSource is specified for the KML layer, the data may be filtered for each KML item prior to evaluating the item expressions. Following is a detailed explanation of the properties involved in evaluating KML item expressions. Note that in all those expressions, the special variable kmlItemName may be used, and refers to the KML item name that is currently being processed.
• ItemFilterExpr: if (and only if) a RecordSource is specified on the KML layer, this filter is applied to the retrieved data prior to evaluating other expressions. For example, if the layer's record source contains a Country field, and the KML file includes country items, the following filter:
  kmlItemName=Country
  will ensure that for each KML item, other item expressions will evaluate with data corresponding to the current item's country.
• ItemTrackExpr: if specified, determines whether an item is used to automatically center/zoom the map. If left empty, true is assumed.
• ItemVisibleExpr: if specified, determines an item's visibility. If left empty, true is assumed.
• ItemStyleExpr: if this expression evaluates to a valid style name in the KmlItemStyles collection (of the current or any other Map in the report), this style is applied to the item. This may be used for instance to fill different states with different colors depending on a data value such as orders total for that state.
• ItemStyle.ItemNameExpr: the KML item style itself contains one calculated property, the item's name. This allows to suppress the name rendered on the map, or replace it with report data (such as orders total).