Geospatial PDF

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Geospatial PDF is a set of geospatial extensions to the Portable Document Format (PDF) that relate a region in the document page to a region in physical space. The establishment of this relationship is a process of georeferencing. The georeferencing metadata for geospatial PDF is most commonly encoded in one of two ways: the OGC best practice; and as Adobe's proposed geospatial extensions to ISO 32000.

Features commonly associated with geospatial PDF are simply features of PDF:

  • the ability to graphically represent vector and raster information (content and imaging model PDF 1.0)
  • the separation of graphics content into different layers (optional content PDF 1.5)
  • the association of tabular information with graphical features (user properties PDF 1.6)

However, in combination with the georeferencing metadata, geospatial PDF is a compelling mechanism for the dissemination of geospatial information and intelligence.

TerraGo pionereed the georeferencing of PDF files with their GeoPDF-branded map and imagery products produced from their software applications, although a TerraGo GeoPDF and a geospatial PDF are not entirely the same thing. GeoPDF products originally used the OGC best practice to encode the georeferencing metadata, but after the release of the Adobe extensions may contain either the Adobe or OGC encodings.

ISO 32000-2 (PDF 2.0), currently under development, will incorporate geospatial PDF features.

Applications creating geospatial PDFs[edit]

Applications reading geospatial PDFs[edit]

The geospatial PDF is considered a Portable Document Format (following the PDF 1.7 specification) file containing information that is required to georeference location data.[1] It is an open specification developed and maintained by Adobe Systems for use by developers to create conforming readers and writers so that there is interoperability among Adobe and other software products.[2] These software products include, but are not limited to, the Avenza MAPublisher and Geographic Imager plugins for the Adobe Creative Suite or ESRI ArcGIS.

A geospatial PDF can contain geometry such as points, lines, and polygons. These, for example, could represent building locations, road networks and city boundaries, respectively. The specification also allows geometry to have attributes, such as a name or identifying type.

Overview[edit]

The popularity of geographic information systems (GIS) and geospatial technology amongst its users has increased the need to share information.[3] However, an obstacle to sharing geospatial data can sometimes be the large file sizes or that the end recipient does not have the appropriate software or reader. The PDF format is widely accepted and is considered the de facto standard for printable documents on the web. This means that users do not require the any proprietary plug-in to read geospatial PDFs created following the PDF 1.7 specification, which was published as ISO 32000-1 standard.[4]

Naming[edit]

The geospatial PDF described here should not be confused with GeoPDF, a trademark used to brand geospatial PDF files created by TerraGo software. There are no restrictions for using either the OGC best practice or Adobe's proposed geospatial extensions to ISO 32000 to create applications which consume or produce geospatial PDF files. Adobe Acrobat and Reader support consumption of both of these georeferencing encodings. Adobe-specified geospatial PDF files and Terrago GeoPDF files although similar in principal are not the same thing and are not created in the same manner.

Uses[edit]

There are many uses for a geospatial PDF. After importing geospatial data into PDF, one can use the data in a variety of ways:[5]

  • Find and mark location coordinates.
  • Measure distance, perimeter, and area.
  • Change the coordinate system and measurement units.
  • Copy location coordinates to the clipboard, and then use them to show locations in several web mapping services.
  • Register a raster image to create a geospatially aware PDF.

Support[edit]

There are several software developers that adhere to the PDF 1.7 specification for writing geospatial PDF files:

  • Avenza Systems
  • Bentley
  • ESRI
  • Pitney Bowes
  • SAFE Software
  • TerraGo Technologies

See also[edit]

References[edit]

External links[edit]