On 03/11/2013 12:18 AM, Lester Anderson wrote:
On 11 March 2013 00:54, Alex Mandel <tech_...@wildintellect.com> wrote:
On 03/10/2013 03:49 PM, Lester Anderson wrote:
On 10 March 2013 22:22, Alex Mandel <tech_...@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
I opened it in QGIS, then did a file Save As... shp in the new projection.
I tried re-projecting the geojson to geojson and it didn't render right
either. So I think I've found a bug in the projection tool or renderer.
I'll note that it's happened to me with Geotiff too, polar projection
ends up looking like pacman.
Thanks,
Alex
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