[Qgis-user] Map graticules in QGIS

[Lester Anderson]

On 11 March 2013 00:54, Alex Mandel <tech_dev at wildintellect.com> wrote:

> On 03/10/2013 03:49 PM, Lester Anderson wrote:
> > On 10 March 2013 22:22, Alex Mandel <tech_dev at wildintellect.com> wrote:
> >
> >> On 03/10/2013 03:13 PM, Lester Anderson wrote:
> >>
> >>> Hello,
> >>>
> >>> The one major element missing from the otherwise great Quantum GIS, is
> >>> that
> >>> of easy setup map graticules. There is a basic way of doing simple
> ones in
> >>> the print composer which is fine for geographic (WGS84) or UTM etc type
> >>> projections, but will not work for conic or stereographic etc.
> >>>
> >>> Is there a plugin for doing this work (that is built-in to layout mode
> in
> >>> ArcGIS) or is this an upgrade/update that will be available in a new
> >>> release?
> >>>
> >>> Generating a vector grid does not work properly in 1.8.0, and certainly
> >>> only partially completes a Polar Stereographic layout. There are
> clearly
> >>> flaws that need to be addressed. If there is a reliable workaround for
> >>> this, it would be good to know.
> >>>
> >>> Lester
> >>>
> >>>
> >> A workaround is to make the graticule in WGS84 and reproject it to the
> >> desired end projection. I found that it doesn't curve well so I wrote
> this
> >> script to make graticules with a higher points density that projects
> well.
> >>
> >> https://github.com/**wildintellect/pyGraticule<
> https://github.com/wildintellect/pyGraticule>
> >>
> >> I hope to work it into QGIS at a later point, but you can use it
> >> standalone with python to make what you need, import and reproject.
> >>
> >> Thanks,
> >> Alex
> >>
> >>
> > Hi Alex,
> >
> > I have tried the route you suggested. I am working on Antarctic data, so
> > generated a vector grid for 0-360 in X (at 10 degrees) and latitude (-90
> to
> > -60) in 10 degrees. That all worked fine in WGS84. However, reprojecting
> to
> > Antarctic Polarstreographic did not project correctly with less than half
> > the meridians and no latitudes.
> >
> > Cheers
> > Lester
> >
>
> This will probably get stripped from the list but I've attached a shp I
> made that should be what you need. Let me know if you need me to upload
> it to server for download.
>
> Note projection on the fly has some odd bug that makes 180/-180
> disappear, I've not spent enough time to figure out what that is.
>
> What I did:
> Used my pyGraticule script modified to go from -90,1
> Reprojected to Polar EPSG:3031 as a shapefile
>
> I'm trying to remember how I did
> http://geography.ucdavis.edu/image/499
> If I remember I'll post some more details.
>
> Thanks,
> Alex
>
>
> Hi Alex,

That worked very well. I had a look at the Python script and I note that it
generates a GeoJSON format file. How do you convert to a shapefile?

Hopefully something along the lines of the script will be built in to QGis,
the OTF reprojection of somethings does fall over.

Cheers
Lester
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