How to improve sentence alignment of pdf files

Example: Sentences as paragraphs

Hallitus esitteli maaliskuussa 2009 uuden Ráđđehus ovdanbuvttii njukčamánus 2009 ođđa
vähemmistöpoliittisen strategian esityksessään unnitlogopolitihkalaš strategiija proposišuvnnas Från
Tunnustamisesta omaan valtaan – Hallituksen kansallisia strategiija nášuvnnalaš unnitloguid váras) (prop.
vähemmistöjä koskeva strategia (esitys 2008/2009:158). 2008/2009:158).
Strategia merkitsee useita muutoksia, jotka koskevat Strategiija sisdoallá máŋga rievdadusa
kansallisten vähemmistöjen oikeuksien vahvistamista ja nannen dihte daid nášuvnnalaš unnitloguid vuoigatvuođaid ja
vähemmistöpolitiikan toteuttamisambitioiden parantamista. alidit gudneáŋgirvuođa got unnitlogopolitihkka galgá
Hallitus panostaa 70 miljoonaa kruunua uudistukseen, jota čađahuvvot. Ráđđehus bidjá 70 miljovnna ruvnnu reforbmii mii
aletaan toteuttaa vuodesta 2010. galgá čađahuvvot 2010 rájis.

Above is an example of a sentence alignment of two pdf documents. We see that sentences have been cut off in the middle. The reason for this is that these pdf documents have been converted as if each sentence is a paragraph.

The name of the file with this content is prestable/tmx/fin2sme/admin/lansstyrelsen.se/faktablad_finska.pdf.tmx.html

To fix this, one has to:

  1. Find the names of the metadata files belonging to the above file. Run the command realign --files prestable/tmx/fin2sme/admin/lansstyrelsen.se/faktablad_finska.pdf.tmx.html
    Note the metadata names that are printed to the terminal.
  2. Open the metadata files, change the line <xsl:variable name="linespacing" select="''"/> to become <xsl:variable name="linespacing" select="'all=2'"/>
    Save the files.
  3. Run the command realign prestable/tmx/fin2sme/admin/lansstyrelsen.se/faktablad_finska.pdf.tmx.html
  4. Reload prestable/tmx/fin2sme/admin/lansstyrelsen.se/faktablad_finska.pdf.tmx.html in the web browser to see if the sentence alignment has been improved.

The above steps improves the situation somewhat, but the sentence alignment has not become perfect.

General approach to improving sentence alignment

To improve the sentence alignment, one must improve the quality of the converted xml file. The general steps are:

  1. Run the command realign --files <path-to-tmx-html-file> to find the names of metadata and converted files.
  2. Have a look at the converted files to see if they are of bad quality
  3. Set a variable in the metadata files to try to improve the quality.
  4. Run the command realign --convert <path-to-tmx-html-file> to reconvert the files
  5. Repeat the above steps until the quality of the converted files seem to be ok, then run realign <path-to-tmx-html-file> to realign the sentences
  6. Open <path-to-tmx-html-file> in a web browser. If alignment is good, commit modified files. If not, repeat the steps above.

Improve sentence alignment of pdf files

When the sentence alignment between two pdf files is bad, it is possible to improve it a lot by editing the metadata file and setting various variables that are specific to pdf files.

The following variables in the metadata file affect the content of the converted file:

skip_pages
skip specific pages that are not wanted in the converted file
right_margin, left_margin, top_margin, bottom_margin
remove text above, below, to the right and left of the main content. This is typically removes page numbers, foot notes, reoccuring page headers and footers, etc.
inner_*_margin
remove a rectangle shaped part of the page
linespacing
as the above example shows, if line spacing in a document is larger than the default 1.5, text lines will be converted to paragraphs. To improve this, set a larger value for this.

A more thorough documentation of these variables are found in the metadata template file.