The directives processed by the AIS reader are listed below. The suffixes shown are prefixed by the current <ReaderKeyword> in a mapping file. By default, the <ReaderKeyword> for the AIS reader is AIS.
DATASET
The value for this directive is the name of a single ASCII-encoded text file that contains AIS messages. The typical extensions of these files are .txt and .log.
Mapping File Syntax
AIS_DATASET “C:\DATA\AIS\myAISmessages.txt”
Required/Optional
Required
Workbench Parameter
Source AIS File
MESSAGE_WAIT_TOLERANCE
The value for this directive is an integer which determines the number of messages that the reader will allow to pass before determining that a multi-part message that is only partially received is incomplete.
In AIS, longer messages are split into multiple parts which are related by an ID. However, the message IDs used when transmitting are not unique. This leads to the possibility of unrelated message pieces which have the same ID to be combined. To prevent this, partially received multi-part messages are dropped as incomplete if the rest of the message is not found within the next set of incoming messages. The size of this set is determined by this parameter.
Required/Optional
Optional
Mapping File Syntax
<ReaderKeyword>_MESSAGE_WAIT_TOLERANCE <integer>
Values
Default value: 40
Workbench Parameter
Multi-part Message Wait Tolerance
SEARCH_ENVELOPE
Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that interact with the bounding box are returned.
If all four coordinates of the search envelope are specified as 0, the search envelope will be disabled.
Mapping File Syntax
<ReaderKeyword>_SEARCH_ENVELOPE <minX> <minY> <maxX> <maxY>
Note: If all four coordinates of the search envelope are specified as zero, the search envelope will be disabled.
Required/Optional
Optional
Workbench Parameter
Minimum X, Minimum Y, Maximum X, Maximum Y
SEARCH_ENVELOPE_COORDINATE_SYSTEM
This directive specifies the coordinate system of the search envelope if it is different than the coordinate system of the data.
The COORDINATE_SYSTEM directive, which specifies the coordinate system associated with the data to be read, must always be set if the SEARCH_ENVELOPE_COORDINATE_SYSTEM directive is set.
If this directive is set, the minimum and maximum points of the search envelope are reprojected from the SEARCH_ENVELOPE_COORDINATE_SYSTEM to the reader COORDINATE_SYSTEM prior to applying the envelope.
Required/Optional
Optional
Mapping File Syntax
<ReaderKeyword>_SEARCH_ENVELOPE_COORDINATE_SYSTEM <coordinate system>
Workbench Parameter
Search Envelope Coordinate System
CLIP_TO_ENVELOPE
This directive specifies whether or not FME should clip features to the envelope specified in the SEARCH_ENVELOPE directive.
Values
YES | NO (default)
Mapping File Syntax
<ReaderKeyword>_CLIP_TO_ENVELOPE [yes | no]
Workbench Parameter
Clip To Envelope