# Filter criteria for landmarks

The following table describes the different criteria by which you can search for landmarks and lists the required `Filter` object properties per criterion. Table: Filter object properties for a landmark search describes the actual properties. To search for landmarks, specify the `Filter` properties for one or more criteria.

Table: Landmark search criteria
Criterion | Description | Properties to specify
--- | --- | ---
Area | You can search for landmarks in a particular geographical area. Specify the search area by providing the enclosing latitudes and longitudes: -90 <= South Latitude <= North Latitude <= +90 -180 <= West Longitude <= East Longitude <= +180 | `BoundedArea` `[MaximumMatches]` `[PreviousMatchesOnly]`
Category | You can search for landmarks by category. The category name search is case sensitive and does not support wild cards. | `CategoryName` `[MaximumMatches]` `[PreviousMatchesOnly]`
Nearest | You can search for landmarks closest to a specific location (a set of coordinates). To narrow down the search results, specify `MaximumDistance` from the location. If `CoverageRadiusOption` is set to `true`, the system takes into account the coverage radius of a landmark, so that the effective distance considered is the distance to the center of a landmark minus its coverage radius. In other words, if the distance between the source location and the border of a landmark's coverage area falls within `MaximumDistance`, the landmark is returned by `GetList`. | `LandmarkPosition` `CoverageRadiusOption` `MaximumDistance` `[MaximumMatches]` `[PreviousMatchesOnly]`
Text | You can search for landmarks based on a name or description. The text search is not case sensitive and supports wild cards, for example "?" (single character) and "*" (zero or more characters). | `LandmarkName` `LandmarkDesc` `[MaximumMatches]` `[PreviousMatchesOnly]`

The following table describes the `Filter` object properties for `GetList` calls that retrieve information about landmarks.

Table: Filter object properties for a landmark search
Property | Description | Type | Value
--- | --- | --- | ---
`[DatabaseURI]` | Specifies the landmark database in which to search for landmarks. If this is not specified, the search is performed on the default database. | string | Maximum length 255 characters
`[LandmarkName]` | Specifies the landmark name to search by. This is checked against the `LandmarkName` property of a landmark. This string is not case sensitive and supports wild cards, for example "?" (single character) and "*" (zero or more characters). | string | Maximum length 255 characters
`[LandmarkPosition]` | Specifies the source location to search by. The location is expressed as latitude, longitude, and altitude. However, only the latitude and longitude are considered in the search. The source location does not have a coverage radius. The properties of this object are described in Table: LandmarkPosition object properties. Landmarks are returned in order of ascending distance from the source location. | object | See Table: LandmarkPosition object properties.
`[CoverageRadiusOption]` | Specifies whether to take into account the coverage radius of a landmark when calculating the distance between the source location and the landmark. If set to `true`, the effective distance considered is the distance to the center of a landmark minus its coverage radius, that is, the distance to the border of the landmark's coverage area. If set to `false`, the distance considered is the distance to the center of a landmark. That is, the landmark's coverage area is not considered. The default value is `false`. | boolean | Possible values: `true` `false`
`[MaximumDistance]` | Specifies the maximum distance in meters from the source location. Landmarks that fall outside this radius are not returned by `GetList`. If `CoverageRadiusOption` is set to `false`, the distance considered is the distance to the center of a landmark. If `CoverageRadiusOption` is set to `true`, the distance considered is the distance to the center of a landmark minus its coverage radius, that is, the distance to the border of the landmark's coverage area. | number |
`[CategoryName]` | Specifies the landmark category name to search by. | string | Maximum length 124 characters
`[LandmarkDesc]` | Specifies the text to be searched for in landmark descriptions. This is checked against the `LandmarkDesc` property of a landmark. This string is not case sensitive and supports wild cards, for example "?" (single character) and "*" (zero or more characters). | string | Maximum length 255 characters
`[BoundedArea]` | Specifies the geographical area in which to search for landmarks. The area is defined as enclosing NSEW latitudes and longitudes: -90 <= South Latitude <= North Latitude <= +90 -180 <= West Longitude <= East Longitude <= +180 The properties of this object are described in Table: BoundedArea object properties. | object | See Table: BoundedArea object properties.
`[MaximumMatches]` | Specifies the maximum number of landmark items to retrieve. If this property is not specified, `GetList` returns all landmarks matching the search criteria. | number |
`[PreviousMatchesOnly]` | Specifies whether to perform the search on previous search results only: If set to `true`, `GetList` searches for matching landmarks in previous search results only. If set to `false`, `GetList` performs a new search on the entire database. The default value is `false`. | boolean | Possible values: `true` `false`

Table: BoundedArea object properties
Property | Description | Type | Value
--- | --- | --- | ---
`BoundedArea.NorthLatitude` | Specifies the northern-most latitude of the search area in WGS 84 datum format. Note: `NorthLatitude` >=`SouthLatitude` | number | [-90.00, +90.00]
`BoundedArea.SouthLatitude` | Specifies the southern-most latitude of the search area in WGS 84 datum format. Note: `SouthLatitude` <= `NorthLatitude` | number | [-90.00, +90.00]
`BoundedArea.EastLongitude` | Specifies the eastern longitude of the search area in WGS 84 datum format. Note: `EastLongitude` >= `WestLongitude` | number | [-180.00, +180.00]
`BoundedArea.WestLongitude` | Specifies the western longitude of the search area in WGS 84 datum format. Note: `WestLongitude` <= `EastLongitude` | number | [-180.00, +180.00]