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50-592: The Canada Flight Supplement ( CFS ) (French: Supplément de vol Canada ) is a joint civil/military publication and is a supplement of the Aeronautical Information Publication (AIP Canada). It is the nation's official airport directory. It contains information on all registered Canadian and certain Atlantic aerodromes and certified airports. The CFS is published, separately in English and French, as

100-622: A page description . PDF has (as of version 2.0) 25 graphics state properties, of which some of the most important are: As in PostScript, vector graphics in PDF are constructed with paths . Paths are usually composed of lines and cubic Bézier curves , but can also be constructed from the outlines of text. Unlike PostScript, PDF does not allow a single path to mix text outlines with lines and curves. Paths can be stroked, filled, fill then stroked, or used for clipping . Strokes and fills can use any color set in

150-496: A PDF are: In later PDF revisions, a PDF document can also support links (inside document or web page), forms, JavaScript (initially available as a plugin for Acrobat 3.0), or any other types of embedded contents that can be handled using plug-ins. PDF combines three technologies: PostScript is a page description language run in an interpreter to generate an image. It can handle graphics and has standard features of programming languages such as branching and looping . PDF

200-450: A PDF. Within text strings, characters are shown using character codes (integers) that map to glyphs in the current font using an encoding . There are several predefined encodings, including WinAnsi , MacRoman , and many encodings for East Asian languages and a font can have its own built-in encoding. (Although the WinAnsi and MacRoman encodings are derived from the historical properties of

250-420: A PostScript file could be accurately rendered only as the cumulative result of executing all preceding commands to draw all previous pages—any of which could affect subsequent pages—plus the commands to draw that particular page, and there was no easy way to bypass that process to skip around to different pages. Traditionally, to go from PostScript to PDF, a source PostScript file (that is, an executable program)

300-477: A Web browser plugin without waiting for the entire file to download, since all objects required for the first page to display are optimally organized at the start of the file. PDF files may be optimized using Adobe Acrobat software or QPDF . Page dimensions are not limited by the format itself. However, Adobe Acrobat imposes a limit of 15 million by 15 million inches, or 225 trillion in (145,161 km ). The basic design of how graphics are represented in PDF

350-557: A digital AIP is a digital version of the paper AIP, usually available in PDF format, while an electronic AIP is available in PDF as well as other formats, more suitable for reading on the screen and for electronic data exchange. Many countries around the world provide digital AIPs either on CD-ROM subscription or on a Web site. The external links section below lists AIPs which aim to follow the EUROCONTROL eAIP Specification. The current AIRAC cycle

400-452: A page description as an inline image .) Images are typically filtered for compression purposes. Image filters supported in PDF include the following general-purpose filters: Normally all image content in a PDF is embedded in the file. But PDF allows image data to be stored in external files by the use of external streams or Alternate Images . Standardized subsets of PDF, including PDF/A and PDF/X , prohibit these features. Text in PDF

450-617: A paper book by Nav Canada and is issued once every 56 days on the ICAO AIRAC schedule. The CFS was published by Natural Resources Canada on behalf of Transport Canada and the Department of National Defence until 15 March 2007 edition, at which time Nav Canada took over production. The CFS presents runway data, arrival and departure procedures, air traffic control (ATC) and other radio frequencies and services such as fuel , hangarage that are available at each listed aerodrome. As well,

500-417: A paper for a project then code-named Camelot, in which he proposed the creation of a simplified version of PostScript called Interchange PostScript (IPS). Unlike traditional PostScript, which was tightly focused on rendering print jobs to output devices, IPS would be optimized for displaying pages to any screen and any platform. Adobe Systems made the PDF specification available free of charge in 1993. In

550-439: A printing device. PostScript was not intended for long-term storage and real-time interactive rendering of electronic documents to computer monitors , so there was no need to support anything other than consecutive rendering of pages. If there was an error in the final printed output, the user would correct it at the application level and send a new print job in the form of an entirely new PostScript file. Thus, any given page in

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600-469: A result, files that use a small amount of transparency might be viewed acceptably by older viewers, but files making extensive use of transparency could be viewed incorrectly by an older viewer. The transparency extensions are based on the key concepts of transparency groups , blending modes , shape , and alpha . The model is closely aligned with the features of Adobe Illustrator version 9. The blend modes were based on those used by Adobe Photoshop at

650-469: A stream may be used instead of the ASCII cross-reference table and contains the offsets and other information in binary format. The format is flexible in that it allows for integer width specification (using the /W array), so that for example, a document not exceeding 64  KiB in size may dedicate only 2 bytes for object offsets. At the end of a PDF file is a footer containing If a cross-reference stream

700-502: A variety of content besides flat text and graphics including logical structuring elements, interactive elements such as annotations and form-fields, layers, rich media (including video content), three-dimensional objects using U3D or PRC , and various other data formats . The PDF specification also provides for encryption and digital signatures , file attachments, and metadata to enable workflows requiring these features. The development of PDF began in 1991 when John Warnock wrote

750-471: Is 2411 (effective 31 Oct 2024). Note: * = leap year containing 29 Feb (2016, 2020, 2024, 2028, etc.) EUROCONTROL : PDF This is an accepted version of this page Portable Document Format ( PDF ), standardized as ISO 32000 , is a file format developed by Adobe in 1992 to present documents , including text formatting and images, in a manner independent of application software , hardware , and operating systems . Based on

800-415: Is a subset of PostScript, simplified to remove such control flow features, while graphics commands remain. PostScript was originally designed for a drastically different use case : transmission of one-way linear print jobs in which the PostScript interpreter would collect a series of commands until it encountered the showpage command, then execute all the commands to render a page as a raster image to

850-464: Is also a shading pattern , which draws continuously varying colors. There are seven types of shading patterns of which the simplest are the axial shading (Type 2) and radial shading (Type 3). Raster images in PDF (called Image XObjects ) are represented by dictionaries with an associated stream. The dictionary describes the properties of the image, and the stream contains the image data. (Less commonly, small raster images may be embedded directly in

900-465: Is called an embedded font while the former is called an unembedded font . The font files that may be embedded are based on widely used standard digital font formats: Type 1 (and its compressed variant CFF), TrueType , and (beginning with PDF 1.6) OpenType . Additionally PDF supports the Type 3 variant in which the components of the font are described by PDF graphic operators. Fourteen typefaces, known as

950-418: Is not being used, the footer is preceded by the trailer keyword followed by a dictionary containing information that would otherwise be contained in the cross-reference stream object's dictionary: Within each page, there are one or multiple content streams that describe the text, vector and images being drawn on the page. The content stream is stack-based , similar to PostScript. There are two layouts to

1000-541: Is not required in situations where a PDF file is intended only for print. Since the feature is optional, and since the rules for tagged PDF were relatively vague in ISO 32000-1, support for tagged PDF among consuming devices, including assistive technology (AT), is uneven as of 2021. ISO 32000-2, however, includes an improved discussion of tagged PDF which is anticipated to facilitate further adoption. An ISO-standardized subset of PDF specifically targeted at accessibility, PDF/UA ,

1050-434: Is organized using ASCII characters, except for certain elements that may have binary content. The file starts with a header containing a magic number (as a readable string) and the version of the format, for example %PDF-1.7 . The format is a subset of a COS ("Carousel" Object Structure) format. A COS tree file consists primarily of objects , of which there are nine types: Comments using 8-bit characters prefixed with

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1100-402: Is represented by text elements in page content streams. A text element specifies that characters should be drawn at certain positions. The characters are specified using the encoding of a selected font resource . A font object in PDF is a description of a digital typeface . It may either describe the characteristics of a typeface, or it may include an embedded font file . The latter case

1150-439: Is used as the basis for generating PostScript-like PDF code (see, e.g., Adobe Distiller ). This is done by applying standard compiler techniques like loop unrolling , inlining and removing unused branches, resulting in code that is purely declarative and static. The end result is then packaged into a container format , together with all necessary dependencies for correct rendering (external files, graphics, or fonts to which

1200-447: Is very similar to that of PostScript, except for the use of transparency, which was added in PDF 1.4. PDF graphics use a device-independent Cartesian coordinate system to describe the surface of a page. A PDF page description can use a matrix to scale , rotate , or skew graphical elements. A key concept in PDF is that of the graphics state , which is a collection of graphical parameters that may be changed, saved, and restored by

1250-555: The PostScript language, each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts , vector graphics , raster images and other information needed to display it. PDF has its roots in "The Camelot Project" initiated by Adobe co-founder John Warnock in 1991. PDF was standardized as ISO 32000 in 2008. The last edition as ISO 32000-2:2020 was published in December 2020. PDF files may contain

1300-533: The Windows and Macintosh operating systems, fonts using these encodings work equally well on any platform.) PDF can specify a predefined encoding to use, the font's built-in encoding or provide a lookup table of differences to a predefined or built-in encoding (not recommended with TrueType fonts). The encoding mechanisms in PDF were designed for Type 1 fonts, and the rules for applying them to TrueType fonts are complex. For large fonts or fonts with non-standard glyphs,

1350-419: The standard 14 fonts , have a special significance in PDF documents: These fonts are sometimes called the base fourteen fonts . These fonts, or suitable substitute fonts with the same metrics, should be available in most PDF readers, but they are not guaranteed to be available in the reader, and may only display correctly if the system has them installed. Fonts may be substituted if they are not embedded in

1400-574: The AD section where details and charts of all public aerodromes are published. AIPs are kept up-to-date by regular revision on a fixed cycle. For operationally significant changes in information, the cycle known as the AIRAC (Aeronautical Information Regulation And Control) cycle , first introduced in 1964, is used: revisions are produced every 56 days (double AIRAC cycle) or every 28 days (single AIRAC cycle). These changes are received well in advance so that users of

1450-506: The CFS contains useful reference pages, including interception instructions for civil aircraft, chart updating data and search and rescue information. Most pilots flying in Canada carry a copy of the CFS in case a weather or mechanical diversion to another airport becomes necessary. The Canada Flight Supplement is made up of seven sections: Carrying "current aeronautical charts and publications covering

1500-566: The Nav Canada Collaborative Flight Planning Services (CFPS) or by contacting the appropriate regional Nav Canada Flight Information Centre . While Nav Canada's CFS has the monopoly on paper-version airport directories in Canada, there are several competing internet publications, including the Canadian Owners and Pilots Association 's Places to Fly user-editable airport directory. Nav Canada also publishes

1550-429: The PDF files: non-linearized (not "optimized") and linearized ("optimized"). Non-linearized PDF files can be smaller than their linear counterparts, though they are slower to access because portions of the data required to assemble pages of the document are scattered throughout the PDF file. Linearized PDF files (also called "optimized" or "web optimized" PDF files) are constructed in a manner that enables them to be read in

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1600-667: The Water Aerodrome Supplement (WAS) (French: Canada Supplément hydroaérodromes ), as a single volume in English and French. This contains information on all Canadian water aerodromes as shown on visual flight rules (VFR) charts and other information such as navaids . The WAS is published on an annual basis. Aeronautical Information Publication The structure and contents of AIPs are standardized by international agreement through ICAO. AIPs normally have three parts – GEN (general), ENR (en route) and AD (aerodromes). The document contains many charts; most of these are in

1650-573: The aeronautical data can update their flight management systems ( FMS ). For insignificant changes, the published calendar dates are used. In some countries the AIP is informally known as the Airman's Manual or the Air Pilot . EUROCONTROL has published a specification for an electronic AIP (eAIP). The eAIP Specification aims to harmonise the structure and presentation of AIPs for digital media. In this respect,

1700-508: The contents. PDF 2.0 defines 256-bit AES encryption as the standard for PDF 2.0 files. The PDF Reference also defines ways that third parties can define their own encryption systems for PDF. PDF files may be digitally signed, to provide secure authentication; complete details on implementing digital signatures in PDF are provided in ISO 32000-2. PDF files may also contain embedded DRM restrictions that provide further controls that limit copying, editing, or printing. These restrictions depend on

1750-411: The document refers), and compressed . Modern applications write to printer drivers that directly generate PDF rather than going through PostScript first. As a document format, PDF has several advantages over PostScript: Its disadvantages are: PDF since v1.6 supports embedding of interactive 3D documents: 3D drawings can be embedded using U3D or PRC and various other data formats. A PDF file

1800-411: The document root. This dictionary contains an array of Optional Content Groups (OCGs), each describing a set of information and each of which may be individually displayed or suppressed, plus a set of Optional Content Configuration Dictionaries, which give the status (Displayed or Suppressed) of the given OCGs. A PDF file may be encrypted , for security, in which case a password is needed to view or edit

1850-527: The early years PDF was popular mainly in desktop publishing workflows, and competed with several other formats, including DjVu , Envoy , Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format. PDF was a proprietary format controlled by Adobe until it was released as an open standard on July 1, 2008, and published by the International Organization for Standardization as ISO 32000-1:2008, at which time control of

1900-406: The full implementation of the ISO 32000-1 specification. These proprietary technologies are not standardized, and their specification is published only on Adobe's website. Many of them are not supported by popular third-party implementations of PDF. ISO published version 2.0 of PDF, ISO 32000-2 in 2017, available for purchase, replacing the free specification provided by Adobe. In December 2020,

1950-402: The graphics state, including patterns . PDF supports several types of patterns. The simplest is the tiling pattern in which a piece of artwork is specified to be drawn repeatedly. This may be a colored tiling pattern , with the colors specified in the pattern object, or an uncolored tiling pattern , which defers color specification to the time the pattern is drawn. Beginning with PDF 1.3 there

2000-494: The imaging model. A tagged PDF (see clause 14.8 in ISO 32000) includes document structure and semantics information to enable reliable text extraction and accessibility . Technically speaking, tagged PDF is a stylized use of the format that builds on the logical structure framework introduced in PDF 1.3. Tagged PDF defines a set of standard structure types and attributes that allow page content (text, graphics, and images) to be extracted and reused for other purposes. Tagged PDF

2050-440: The objects in the file, and also allows for small changes to be made without rewriting the entire file ( incremental update ). Before PDF version 1.5, the table would always be in a special ASCII format, be marked with the xref keyword, and follow the main body composed of indirect objects. Version 1.5 introduced optional cross-reference streams , which have the form of a standard stream object, possibly with filters applied. Such

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2100-552: The percent sign ( % ) may be inserted. Objects may be either direct (embedded in another object) or indirect . Indirect objects are numbered with an object number and a generation number and defined between the obj and endobj keywords if residing in the document root. Beginning with PDF version 1.5, indirect objects (except other streams) may also be located in special streams known as object streams (marked /Type /ObjStm ). This technique enables non-stream objects to have standard stream filters applied to them, reduces

2150-573: The route of the proposed flight and any probable diversionary route" is a requirement under CAR 602.60 (1) (b) for night VFR, VFR over-the-top and instrument flight rules (IFR) flights. This Canadian Aviation Regulation (CAR) does not specifically require carriage of a copy of the CFS, but that is one way to satisfy the regulation. Because information in the CFS may be out of date, particularly with regard to such issues as runway closures and fuel availability, pilots should check NOTAMs before each flight. NOTAM information in Canada can be obtained from

2200-495: The second edition of PDF 2.0, ISO 32000-2:2020, was published, with clarifications, corrections, and critical updates to normative references (ISO 32000-2 does not include any proprietary technologies as normative references). In April 2023 the PDF Association made ISO 32000-2 available for download free of charge. A PDF file is often a combination of vector graphics , text, and bitmap graphics . The basic types of content in

2250-423: The size of files that have large numbers of small indirect objects and is especially useful for Tagged PDF . Object streams do not support specifying an object's generation number (other than 0). An index table, also called the cross-reference table, is located near the end of the file and gives the byte offset of each indirect object from the start of the file. This design allows for efficient random access to

2300-432: The special encodings Identity-H (for horizontal writing) and Identity-V (for vertical) are used. With such fonts, it is necessary to provide a ToUnicode table if semantic information about the characters is to be preserved. A text document which is scanned to PDF without the text being recognised by optical character recognition (OCR) is an image, with no fonts or text properties. The original imaging model of PDF

2350-577: The specification passed to an ISO Committee of volunteer industry experts. In 2008, Adobe published a Public Patent License to ISO 32000-1 granting royalty-free rights for all patents owned by Adobe necessary to make, use, sell, and distribute PDF-compliant implementations. PDF 1.7, the sixth edition of the PDF specification that became ISO 32000-1, includes some proprietary technologies defined only by Adobe, such as Adobe XML Forms Architecture (XFA) and JavaScript extension for Acrobat, which are referenced by ISO 32000-1 as normative and indispensable for

2400-448: The time. When the PDF 1.4 specification was published, the formulas for calculating blend modes were kept secret by Adobe. They have since been published. The concept of a transparency group in PDF specification is independent of existing notions of "group" or "layer" in applications such as Adobe Illustrator. Those groupings reflect logical relationships among objects that are meaningful when editing those objects, but they are not part of

2450-481: Was opaque, similar to PostScript, where each object drawn on the page completely replaced anything previously marked in the same location. In PDF 1.4 the imaging model was extended to allow transparency. When transparency is used, new objects interact with previously marked objects to produce blending effects. The addition of transparency to PDF was done by means of new extensions that were designed to be ignored in products written to PDF 1.3 and earlier specifications. As

2500-511: Was first published in 2012. With the introduction of PDF version 1.5 (2003) came the concept of Layers. Layers, more formally known as Optional Content Groups (OCGs), refer to sections of content in a PDF document that can be selectively viewed or hidden by document authors or viewers. This capability is useful in CAD drawings, layered artwork, maps, multi-language documents, etc. Basically, it consists of an Optional Content Properties Dictionary added to

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