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[Piero Cavalieri]

Umberto Nicoletti wrote:

>Ciao,
>
>On 7/21/05, Piero Cavalieri <piero.cavalieri at heidi.it> wrote:
>
>>M. Fioretti wrote:
>>
>>>Greetings,
>>>
>>>I have to build a new website, with a map section. Users must be able
>>>to say "show me path number X, and all the interest points distant
>>>less than 20 KMs from its starting point", where:
>>>
>>>"show me" means generate on demand a png image of the map with all the
>>>         requested data. The image must be printable at the right
>>>         resolution, that is when on paper must be in the exact scale
>>>         (Hmmm, maybe pdf is better for this: which other tools may
>>>         work with Image_GIS to do pdf?)
>>
>>Exact scale could be problematic; Probably you want the user select the
>>area to be printed. In this case, scale will not be preserved. Good thing
>>is that you can place images as percentage of paper's width and height. So
>>you can print in A4, A3, A0, custom dimensions ecc with a unique code
block
>>(but scale will not be presereved...).
>>For pdf there are various libraries. Pdflib is not free (pdfliblite is,
but
>>under certain circusances), but in php manual there are links to other
free
>>pdf libraries (if you use php...).
>>
>
>I currently print to scale using a pdf output format. That is the most
>reliable way to make sure that the image will be printed correctly.

Priniting scale doesn't depends on paper size (if extents remain the same)?

>It has a few drawbacks, though: it does not handle transparency (so
>raster layers will almost alway hidden below vector layers), it is not
>very customizable, it does not support scalebars as they use fixed
>fonts.
>

I import into pdf images from MapServer (main image, scalebar, reference),
where MapServer output is jpeg or png (transparency ok). With pdf libs you
can place  objects where you want (not all libs I tested supports
transparency, however pdflib do it). If you look at chapter 5.3  on pdflib
manual, you can see it's quite easy to embed images.

Piero

>Regards,
>Umberto