[Qgis-user] Qgis Map composer scale distorted in hard copy (printout)

[Sashikumar N]

Hi Andreas,
Thankyou for the reply, I had similar thoughts on the projection, your mail
made me to go for it. I removed the 4326 OTF projection in the layers and
applied it only for the grid.  Tested it for a A4 sheet for the scale and
went for an A0 full color sheet.  I verified the measurements on the sheet,
its very close to the real distance. Thankyou very much for sharing your
thoughts on the problem.

Regards
Sashi

On Tue, 2 Jun 2015 09:31 Andreas Neumann <a.neumann at carto.net> wrote:

>  Hi Sashi,
>
> First when I read your mail I thought - ok, this guy did not print out the
> PDF on  a 100% scale. Forgive me, but I lot of people ignore this option
> and then complain.
>
> But your case seems to be a bit more complex.
>
> What I propose is that you do not use EPSG 4326. Keep using your meter
> based projection and use a different CRS (e.g. EPSG 4326) just for your map
> grid. Since 2.6 (I believe), it is possible to define the CRS for the map
> grid separately and even have multiple grids on the same map. Please use
> this approach and see if it works better.
>
> Getting a correct map scale for CRS 4326 (Plate Caree projection) is hard
> - since at every latitude the scale is different.
>
> Hope this helps,
> Andreas
>
>
> On 01.06.2015 22:49, Sashikumar N wrote:
>
> Dear All,
> This is my first post to the forum as a new member. I seemed to be jinxed
> by a scale distortion problem. I am using windows 8.1 version, Qgis 2.8.1,
> installed as standalone version.
>
>  Here is my problem, I am setting the scale in the Map composer as
> 1:250,000 for a test print of A4 size sheet. i know the  straight line
> distance of two points in the vector layers of map view. The distance is
> 52.5 km approximately. For the above scale it means 1cm = 2500 m (2.5 km).
> For the distance between the known points it should measure as 21 cm in a
> printout. I exported the map composer sheet to pdf file and then printed
> it. Now when i measure the distance between the known points, it measures
> only 17.8 cm instead of 21 cm or the distance on ground is calculated as
> only
> 44.5 km. So for the printed map, the scale is not 1:250,000 as fixed in
> the map composer, but 1:295000
>
>  While printing i have taken care that, auto scaling / fit to page etc
> from printer setting is disabled. So i guess i print as it came out of the
> map composer.
>
>  My question in simple terms: does the map composer scale and printed map
> scale match in a normal course? What is the mistake i am doing. Am i
> ignoring the projection effects or any other basic criteria in creating the
> map composition? How do i make sure that the scale in the printout is same
> as the map composer scale?
>
>
>  Thanks for your help
>
>  ps: All my layers CRS is EPSG 24343 (Kalainpur 1975 / UTM zone 43 N), I
> am using EPSG 4326 OTF to get lat long to be printed on the map. The
> distance between points is measured horizontally across the map.
>
>  --
> Thankyou
> regards
> sashi
>
>
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