FME Readers and Writers 2013 SP1
APT Reader
The APT Reader allows FME to read APT files.
Overview
The APT is a published ASCII format used in design systems. It is a three-dimensional
(3D) system.
APT files store both feature geometry and attribution, and have an .apt file name
extension. The extension is added to the basename of the APT file.
The APT reader supports the storage of point, line, and polygon geometric data in .apt
files. The APT format also stores features with no geometry (which are referred to as
having a geometry of none).
APT Quick Facts
About Quick Facts Tables
Format Type Identifier
APT
Reader/Writer
Reader
Licensing Level
Professional
Dependencies
None
Dataset Type
File base name
Feature Type
Feature Name
Typical File Extensions
.apt
Automated Translation Support
Yes
User-Defined Attributes
No
Coordinate System Support
No
Generic Color Support
No
Spatial Index
Never
Schema Required
Not applicable
Transaction Support
No
Geometry Type Attribute
apt_type
Geometry Support
Geometry
Supported?
Geometry
Supported?
aggregate
no
point
yes
circles
no
polygon
no
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APT Reader
Geometry Support
Geometry
Supported?
Geometry
Supported?
circular arc
no
raster
no
donut polygon
no
solid
no
elliptical arc
no
surface
no
ellipses
no
text
no
line
no
z values
yes
none
yes
Reader Overview
The APT reader then extracts features from a file one at a time, and passes them on to
the rest of the FME for further processing. The reader finishes when it reaches the end
of the file.
APT Reader Parameters
Search Envelope
Use 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.
Clip to Search Envelope
Check this box if you want to remove any portions of exported features outside the
area of interest.
About Mapping File Directives
Most mapping file directives correspond directly to a Reader or Writer parameter. To
see detailed technical information for any format parameters, open the corresponding
Mapping File Directives book in the table of contents.
Feature Representation
In addition to the generic FME feature attributes that FME Workbench adds to all
features (see About Feature Attributes), this format adds the format-specific attributes
described in this section.
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FME Readers and Writers 2013 SP1
APT features consist of geometry and attributes. The attribute names are defined in
the DEF line and there is a value for each attribute in each APT feature.
The table below lists the attributes contained in all APT features.
Attribute Name Contents
apt_type
The APT geometric type of this entity.
Range: apt_point|apt_none
Default: No default
apt_ival
This is the i coordinate to the point that is in normal
vector.
Range: Floating Point Number
Default: Blank
apt_jval
This is the j coordinate to the point that is in normal
vector.
Range: Floating Point Number
Default: Blank
apt_kval
This is the k coordinate to the point that is in normal
vector.
Range: Floating Point Number
Default: Blank
Points
apt_type: apt_point
APT point features specify a single x and y coordinate in addition to any associated
user-defined attributes. There are no special FME attributes for the APT point type.
Currently only point features are supported.
Format Mapping File Directives
Note: FME translations were originally based entirely on Mapping Files. Mapping
files still exist under the surface but the interface has been almost entirely replaced
by Workbench's graphical interface. Information on mapping files is included in this
manual for technical reference purposes.
Mapping Files are ASCII text files that contain a series of rules that specify the FME
readers, writers, and transformations (in Workbench, these are represented by
transformers).
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APT Reader
A mapping file (.fme) is a series of commands for FME to perform. Mapping files use
functions and factories to transform the data. They also contain the definition and
parameters for the readers and writers. A mapping file can be run through the FME
Quick Translator. Before FME Workbench was designed and developed (about 2001),
this was the only way to configure a translation process.
You can create a mapping file either by manually programming it or by using FME
Workbench. In Workbench, there is still an Export as .fme tool on the toolbar. The
Workbench file format itself (.fmw file) is partially a mapping file with an XML header.
When FME runs a workspace it is converted into a mapping file.
Since mapping files are written in a plain ASCII format, so you can use any text editor
to edit them. To see what a mapping file looks like: select one or more transformers in
Workbench, copy them, and then paste them in a text editor. The mapping file
equivalent of those transformers will be pasted.
Directives and Reader/Writer Keywords
Directives are processed by the reader or writer. Directives are prefixed by the
current <ReaderKeyword> or <WriterKeyword> in a mapping file. By default, the
keywords for formats are the format shortname (viewable in the Formats Gallery, or
in the Format Quick Facts tables.
Reader Directives
The following paragraphs contain the directives processed by the APT reader. The
suffixes shown are prefixed by the current <ReaderKeyword> in a mapping file. By
default, the <ReaderKeyword> for the APT reader is APT.
DATASET
Required/Optional: Required
Contains the directory name of the input APT files. The value for this keyword is the
file path of the APT file to be read. A typical mapping file fragment specifying an input
APT dataset looks like:
APT_DATASET /usr/data/apt/aptfile.apt
Workbench Parameter: Source APT File(s)
DEF
Required/Optional
Optional
This keyword defines the APT file, and each APT file must be defined before it can be
read. The definition specifies the base name of the file, and the names and the types of
all attributes. The syntax of a APT DEF line is:
<ReaderKeyword>_DEF <baseName> \
[<attrName> <attrType>]+
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FME Readers and Writers 2013 SP1
The basename specified on the APT DEF lines is constructed by using either the file
name without the extension specified by the DATASET keyword, or using apt_record
(used only when APT is the source).
APT files require at least one attribute to be defined. The attribute definition given
must match the definition of the file being read. If it does not, translation is halted and
the true definition of the APT file’s attributes gets logged to the log file.
The following table shows the attribute types supported.
Field Type
Description
char(<width>)
Character fields store fixed-length strings. The
width parameter controls the maximum number
of characters that can be stored by the field. No
padding is required for strings shorter than this
width.
date
Date fields store dates as character strings with
the format YYYYMMDD.
number(<width>, <decimals>)
Number fields store single and double precision
floating point values. The width parameter is the
total number of characters allocated to the field,
including the decimal point. The decimals
parameter controls the precision of the data and
is the number of digits to the right of the decimal.
logical
Logical fields store TRUE/FALSE data. Data read
or written from and to such fields must always
have a value of either true or false.
The following mapping file fragment defines a APT file DEF line when APT is the source
file format.
APT_DEF apt_record \
apt_ival char(254) \
apt_jval char(254) \
apt_kval char(254)
SEARCH_ENVELOPE
This directive specifies a bounding box used to filter the input features. Only features
that interact with the bounding box are returned. If this directive is not specified, then
all features are returned.This directive is only honoured by the MITAB-based MapInfo
reader in FME. This is the only MapInfo reader available on the UNIX platforms
supported by FME, and can optionally be enabled on Windows platforms by renaming
the mitab.dll in the FME home directory to mapinfo.dll.
Mapping File Syntax
<ReaderKeyword>_SEARCH_ENVELOPE <minX> <minY> <maxX> <maxY>
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APT Reader
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
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