I am using the tabulizer library in r to capture data from a table located inside a PDF on a public website
(https://www.waterboards.ca.gov/sandiego/water_issues/programs/basin_plan/docs/update082812/Chpt_2_2012.pdf).
The example table that I am interested in is on page 23 of the PDF (p. 2-21, document has a couple of blankpages at beginning). The table has a non-standard format and also different symbols (non-alphanumeric characters in the cells).
I want to extract most if not all tables from this document.
I want to end up with a table that has characters with codes (i.e., black circles with 999, white circles with 777, plus signs with -99, etc).
Tabulizer does a good job for the most part converting the dark circles into consistent alphanumeric codes, and keeping the plus signs, but runs into problems on the REC1 column with white
circles, which is odd since it does seems to recognize exotic characters on other columns.
Could anyone please help fix this? I also tried selecting the table area but the output was worse. Below is the r code I am using.
I know I can complete this process by hand for all the tables in the document using PDF's built-in select and export tools but would like to automate the process.
library("tabulizer")
f2 <- "https://www.waterboards.ca.gov/sandiego/water_issues/programs/basin_plan/docs/update082812/Chpt_2_2012.pdf"
tab <- extract_tables(f2, pages = 23, method = 'lattice')
head(tab[[1]])
df <- as.data.frame(tab)
write.csv(df, file = "test.csv")
Related
I have some pdf's with 2-3 passages for every page. every passage is separated by some line gap, but while reading with pymupdf, I cannot see any machine printable separator between passages. is there any other way, other library can do this?
code:
import fitz
from more_itertools import *
doc = fitz.open('IT_past.pdf',)
single_doc = doc.load_page(0) # put here the page number
text=single_doc.get_text('text')
text
page screen shot:
enter image description here
pdf
Full pdf
There is no gap as such, just for the moment as its much easier, lets look closer in your linked viewer rendering :-
So lets replicate what is inside the real PDF (that has no web side html <p> markers) :-
support, product design, HR Management, knowledge process outsourcing for
pharmaceutical companies and large complex projects.
Software exports make up 20 % of India's total export revenue in 2003-04, up from 4.9 %
in 1997.This figure is expected to go up to 44% of annual exports by 2010. Though India
See there is "no gap" just left aligned non justified (ragged) text that needs a style such as a font name and stretched out locations added to hold in a page de-void of line feeds nor true carriage returns. (occasionally there are some backspace or vertical/horizontal moves but generally meaningless in line printer text). Even "Tabs" "Indents" and some spatial characters are normally discarded in a PDF printout.
If you want gaps or line-wrap you need to add them.
A good alternative is export the -layout using poppler or xpdf here to - (console) or pipe it or replace that with a path/name.txt, many other options available like -nopgbrk
xpdf-tools-win-4.04\bin32>pdftotext -f 1 -l 1 -layout IT_past.pdf -
Because of some semantic analysis work, I need identify paragraphs from pdf files with iTextSharp. I know the coordinates of iTextSharp live in the left bottom corner of a page. I find three features to define the paragraph boundaries:
if the horizontal axis of the first word in one line is less than that of the general lines;
if the leading of two consecutive lines is larger than that of the general ones;
if one line ends with "." and the horizontal axis of the ending word is less than that of the other lines
However, I am stuck on the second one. How can I know the general leading between two lines in a paragraph? I mean there are different gaps between two consecutive lines, because some letters like 'f','g' need more space than the others like 'a','n' and so on.
Thanks for your help!
I'm assuming that you are parsing your PDF files using the parser functionality available in iTextSharp. See for instance Extract font height and rotation from PDF files with iText/iTextSharp to see how others have done this before you. A more elaborate article can be found here: Using Open Source PDF Technology to Solve the Unstructured Data Problem in Healthcare
Your question is: how can I calculate the leading? That is: how do I know the distance between the base lines of two consecutive lines?
When you parse a PDF using iTextSharp, you see each line as a series of TextRenderInfo object. These objects allow you to get the base line of the text:
LineSegment baseline = renderInfo.GetBaseline();
Vector startpoint = baseline.GetStartPoint();
This Vector consists of different elements: Getting Coordinates of string using ITextExtractionStrategy and LocationTextExtractionStrategy in Itextsharp
You need startpoint[Vector.I2]. See also: How to detect newline from PDF using iTextSharp
The difference between that value for two consecutive lines give you the value of the leading in its modern meaning. In the old times of printing, every character was a block of a fixed size. Printers (the people, not the machines) put a strip of lead between the rows of blocks to create some extra space between the lines. In modern computing, the word was preserved, but its meaning changed. There are no "blocks" anymore, but you could work with the font size. The font size is an average size of the glyphs in a font. Some glyphs will take more space in the height, some will take less, but taking both the leading (distance between baselines) and the font size (average height of each glyph) into account, you can get a fair idea of the "space between the lines".
I've been looking into a PDF file to understand how it is built.
I noticed that InDesign has created PDFs with text as below (after decompression using pdftk).
0 Tc /Span<</ActualText<FEFF0009>>> BDC
4.018 -0.2 Td
( )Tj
I understand the role of ActualText (for copy/paste/searching) but I'm wondering exactly how I should be interpreting the FEFF0009. It looks like a UTF-16 string with BOM chars to represent a tab character. This seems incorrect as it's really a space. I'm wondering if there is a special meaning here?
.. This seems incorrect as it's really a space.
No, it's really a tab.
14.9.4 Replacement Text
NOTE 1: Just as alternate descriptions can be provided for images and other items that do not translate naturally into text (as described in the preceding sub-clause), replacement text can be specified for content that does translate into text but that is represented in a nonstandard way.
(PDF 32000-1:2008)
The PDF text engine does not support the concept of 'tabs'. In this case, InDesign mimicked the function of a tab character by inserting a space in the text stream, and it could set the space width to match the distance spanned by the original tab or use a large relative positioning for the rest of the text (which it did here: the horizontal displacement of 4.018 in your code snippet).
The general idea is that a space is rendered on the position of the tab, but when you copy this text and paste somewhere else you get a tab character. I suppose the 'space' is only inserted to have something to copy.
This may be a stupid question, but I can't figure it out.
I have made some tables in SPSS. Now I want them over to my latex document.
What I do, it that I right-click the table in SPSS, and press export.
Here I can choose between PDF or .doc. BUT the PDF-file created, generates a file with the table on top of a page (A4 size, with "page 1" at the bottom). I do not want this, I only want the table.
example how it turns out:
Example how I want it to turn out:
If I export to word, I can further save as PDF, but same problem occurs.
Screenshot works, but does not give me the same picture-quality that I prefer.
Do anyone of you have any tips for me?
Thanks :)
Unfortunately SPSS does not provide native table export to Latex. It does provide table export to html and xls, which can post-hoc be converted to Tex tables. PDF output for everything forces to export the full page (very annoying for graphics as well) - but you probably don't want to insert the image of the table (you could crop the PDF if need be), but have a Tex table (in the same font) as your document anyway.
One thing I have done in the past to make the export to text tables with specific markup is to use the PRINT or LIST commands to print the text table to the output (or to a text file) that is closer to the end goal. In this NABBLE post I have some syntax that makes pandoc flavored pipe style markdown tables - it should be pretty clear how that same approach could be used for Tex tables (actually Tex tables should be much simpler).
Here is an example of some code using LIST to make a the markup closer to Tex tables.
DATA LIST FREE / Variable (A1) Mean Median (2F4.2).
BEGIN DATA
A 3.25 2.00
B 2.56 2.50
C 9.87 10.20
END DATA.
*Using LIST to make Latex style table.
STRING Mid (A1) End (A2).
COMPUTE Mid = "&".
COMPUTE End = "//".
LIST /VARIABLES = Variable Mid Mean Mid Median End.
And here is a screen shot of the produced output on my machine.
So here I would still have to copy-paste the text output into my Tex document, (and make the header row).
You can also use OMS to save designed items in a variety of formats, including XML and then use an xml-to-Latex tool such as xmltex. You could probably even generate such a conversion with XSLT from the XML.
From the Viewer, you could also retrieve the table with Python scripting and use a Python-based converter tool.
I am using PDFBox to extract text from PDF.
The PDF has a tabular structure, which is quite simple and columns are also very widely spaced from each-other
This works really well, except that all kinds of horizontal space gets converted into a single space character, so that I cannot tell columns apart anymore (space within words in a column looks just like space between columns).
I appreciate that a general solution is very hard, but in this case the columns are really far apart so that having a simple differentiation between "long spaces" and "space between words" would be enough.
Is there a way to tell PDFBox to turn horizontal whitespace of more then x inches into something other than a single space? A proportional approach (x inch become y spaces) would also work.
The pdftotext C library/tool has a '-layout' switch that tries to preserve the layout. Basically, if I can emulate that with PDFBox, that would be perfect.
There does not seem to be a setting for this, but I was able to modify the source for the PDFTextStripper tool to output a column separator (|) when a "long" space was encountered. In the code where it was building the output line it is possible to look at the x positions of the current and previous letter, and if it is large enough, do something special. PDFTextStripper has lots of protected methods, but turned out to be not really all that extensible. I ended up having to copy the whole class to change a private method.
Looking at the code in there, I call myself lucky that with the particular PDF, this simple approach was successful. A more general solution seems very tricky.
PDF text extraction is difficult.
If the text was output as one big string separated by spaces such as :-
PDFTextOut(" Column 1 Column 2 Column 3");
and you are using a fixed width font such as Courier then you could theoretically calculate the number of spaces between items of text because each character is the same width. If the font is proportional such a Arial then the calculation is harder.
In reality most PDF's generated by individually placing each piece of text directly into its position. Therefore, there is technically no space character or any other characters between columns. The text is just placed into an absolute position on the page.
PDFMoveTo(100,100);
PDFTextOut("Column 1");
PDFMoveTo(250,100);
PDFTextOut("Column 2");
In order to perform data extraction on PDF documents you have to do a little bit more work to find and match column data by using pixel locations as you have mentioned and by making some assumptions and having a little bit of luck.