Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

i have a PDF containing a region of Baltimore city that contains lots of polygons in it. you can download it from here:

http://www.baltimorecity.gov/Portals/0/agencies/planning/public%20downloads/Typology2011%20Final.pdf

I also have a kmz file, containing each part of Baltimore city, you can download it here: https://data.baltimorecity.gov/api/file_data/-gbDlGngMlcHrfsfZepc1QzhJbN42zwUOcIhJ8ZJOVY?filename=Housing%2520Typology%25202008.kmz

All i want to do is to open the kmz file in Qgis, then import the pdf file into qgis as background and then select the city regions with mouse and based on the color of the region in the PDF file, edit the attributes of the kmz file and after all i want to export it as an shape file. How am i able to import the pdf file as a background image and fits it to city regions in order to be able to select the regions regarding the background image?

share|improve this question
    
Why not download the (2008) shapefile and update the attributes? data.baltimorecity.gov/Geographic/Housing-Typology-2008-Shape/… a formal request should get you the 2011 version. –  Mapperz Aug 15 '13 at 19:39
    
@Mapperz, Also that is good too, only thing i need is to import a snapshot image of pdf file into qgis as background and then select different areas on raster layer using that. i need to create a new column named 'Crime Level' in the attribute table and then for purple regions in PDF it will be 5 and so on. do you know how i can do this in details? –  epsi1on Aug 15 '13 at 19:47

1 Answer 1

up vote 2 down vote accepted

It should not be too hard to achieve this by converting the PDF to an image format (say Tiff) and georeferencing that image and projecting it in the same projection as the data you are overlaying. You will not be 100% accurate but with care you can get a good result.

A few random thoughts:

  • As seems typical with so many maps, there are no graticules or tic marks to help you but you could get reference points from Tiger data or maybe even your KMZ.
  • When you convert the image make sure it is NOT saved in a progressive format, especially if you are using GIMP (where this is the default). See my answer in this thread.
  • If you are having trouble opening the KMZ in QGIS, you can open it in Google, save it as a KML and that will open fine.
  • To georeference the image go Raster->Georeferencer
  • It looks like the image has been exported from a GIS rather than scanned from paper, which is a good thing as there will be fewer inaccuracies from paper shrinkage, folding etc.
  • I would convert the KMZ file to a shapefile first and then edit the Shapefile's attributes, just to be sure of preserving the original data, although you can always download it again in this case.
share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.