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On 13/10/2007, Jeff Whitaker <js...@fa...> wrote:

> Adam:  See the basemap examples directory - there's plenty of examples
> there using pylab.colorbar.

Thanks, that was what I was after - the appropriate module and method.

Cheers

Adam

Adam Mercer wrote:
> Hi
>
> Is there a way that I can add a colour bar to a basemap plot detailing
> the value represented by each colour?
>
> Cheers
>
> Adam
>
>   

Adam:  See the basemap examples directory - there's plenty of examples 
there using pylab.colorbar.

-Jeff

-- 
Jeffrey S. Whitaker         Phone : (303)497-6313
NOAA/OAR/CDC  R/PSD1        FAX   : (303)497-6449
325 Broadway                Boulder, CO, USA 80305-3328

On 13/10/2007, Jeff Whitaker <js...@fa...> wrote:

> Adam:  Same as with any other plot created with matplotlib.  You can use
> the 'figsize' keyword to pylab.figure in conjunction with the 'dpi'
> keyword to pylab.savefig.  For details see

Thanks, I was unsure whether or not is used the same system.

Cheers

Adam

Adam Mercer wrote:
> Hi
>
> How can I set the size of the plot produced by basemap, as I need to
> create a nice high resolution plot for a publication?
>
> Cheers
>
> Adam
>   

Adam:  Same as with any other plot created with matplotlib.  You can use 
the 'figsize' keyword to pylab.figure in conjunction with the 'dpi' 
keyword to pylab.savefig.  For details see

http://www.scipy.org/Cookbook/Matplotlib/AdjustingImageSize

-Jeff

-- 
Jeffrey S. Whitaker         Phone : (303)497-6313
NOAA/OAR/CDC  R/PSD1        FAX   : (303)497-6449
325 Broadway                Boulder, CO, USA 80305-3328

Hi

Is there a way that I can add a colour bar to a basemap plot detailing
the value represented by each colour?

Cheers

Adam

Hi

How can I set the size of the plot produced by basemap, as I need to
create a nice high resolution plot for a publication?

Cheers

Adam

Charles Seaton wrote:
> I have noticed that matplotlib.toolkits.basemap.Basemap supports a smaller
> set of projection arguments than the underlying function
> matplotlib.toolkits.basemap.pyproj.Proj and was wondering if there is a
> fundamental limitation on the functionality of Basemap that prevents it from
> handling proj arguments such as x_0, y_0, ellps, datum, and init?
>
> I would like to be able to use all of the very nice functionality built into
> Basemap on standard projections such as Oregon State Plane Coordinate
> System-North NAD27 (which can be generated using pyproj.Proj with the
> following proj arguments:
>
> orspcs_m = matplotlib.toolkits.basemap.pyproj.Proj(\
> proj='lcc',lat_1=44.33333333333334,lat_2=46,lat_0=43.66666666666666,\
> lon_0=-120.5,x_0=609601.2192024384, y_0=0,ellps='clrk66',datum='NAD27')
>
> or even more simply by
> orspcs_m = matplotlib.toolkits.basemap.pyproj.Proj(init='epsg:32026')
> or 
> orspcs_m = matplotlib.toolkits.basemap.pyproj.Proj(init='nad27:3601')
>
> but Basemap() won't accept the necessary arguments
>
> Would this be a matter of modifying the Basemap __init__ function to
> recognize a longer list of possible arguments or is there a larger issue I'm
> not seeing, or a bunch more code that would require modification?
>
> thanks,
>
> Charles Seaton
> Research Associate
> OHSU/ STC-CMOP
>   
Charles:  Unfortunately, there's more to making a map than getting the 
map projection transformation right.  There's lots of special case code 
for different projections in basemap to take care of coastline polygons 
that go over the edge of the map region, drawing of meridians and 
parallels, drawing the map projection boundary, etc.

It looks like the projection you want is lambert conformal with a 
Clark66 ellipsoid.  You should be able to use Basemap with 
projection='lcc', and rsphere set to a tuple that defines the Clark66 
ellipsoid.  Is there a reason that won't work?

-Jeff

-- 
Jeffrey S. Whitaker         Phone : (303)497-6313
NOAA/OAR/CDC  R/PSD1        FAX   : (303)497-6449
325 Broadway                Boulder, CO, USA 80305-3328

Charles Seaton wrote:
> I would like to use a higher resolution coastline than the high resolution
> coastline optionally provided with (specifically, I would like to use the
> NOAA/NOS Medium Resolution Coastline). I can see two ways to do this:
>
> Option 1) Create a coastline file using the in the NOAA/NOS data in the same
> format as the data files used by the basemap toolkit. I couldn't find a
> description of this format, but it appears that it is partially explained by
> the code snippet:
>
> if line.startswith('P'):
>                 area = float(linesplit[5])
>                 west,east,south,north =
> float(linesplit[6]),float(linesplit[7]),float(linesplit[8]),float(linesplit[9])
>                 typ = int(linesplit[3])
>
> So the first line of the existing high resolution coastline is:
> P      0  169598 1 W 79866900.000 -17.53378 190.35911 -34.83044  77.71958
>
> Which should be interpreted as 
> typ = 1
> area = 79866900.000
> west = -17.53378 
> east = 190.35911 
> south = -34.83044  
> north = 77.71958
>
> area is used to control whether this segment of coastline is displayed
> the directions are the bounding box for the coastline segment
> I am not clear on how typ is used (I see it getting manipulated, but I don't
> see it ever getting used), or what its acceptable values are. I am also not
> clear what the first, second and fourth values of the line are (not counting
> the initial 'P'). Any help with this format would be appreciated.
>
> Option 2) Load a coastline by whatever means I choose as a list of lists of
> touples (or some other format?) and then transform those values using the
> basemap object. If the coastline were easily expressed as a pair of lists or
> arrays lon,lat, then I could simply use 
>
> b=basemap(...) 
> coastx,coasty = b(lcoastlon,coastlat)
>
> but the coastline is made up of multiple segments (islands, etc). Is the
> best way to transform a collection of segments simply to loop over the
> segments?
>
> coast = [ [(x11,y11),... (x1n,y1n)], [(x21,y21),... (x2n,y2n)],...
> [(xn1,yn1),...(xnn,ynn)] ]
> newcoast = []
> for c in coast:
>   ln,lt = map(list,zip(*c))
>   x,y = m(ln,lt)
>   newcoast.append(zip(x,y))
>
> Once I have a transformed list of lists of touples, I can replace the
> basemap objects coastsegs
> b.coastsegs = newcoast
>
> and then draw the coastline using the built-in 
> b.drawcoastlines()
>
> Or is there some method that I am missing?
>
>
>   
Charles:  If you can get the coastlines in a shapefile, that's probably 
the easiest way to do it.  See the fillstates.py example for reading in 
and plotting shapefiles on maps.

-Jeff

-- 
Jeffrey S. Whitaker         Phone : (303)497-6313
NOAA/OAR/CDC  R/PSD1        FAX   : (303)497-6449
325 Broadway                Boulder, CO, USA 80305-3328

I have noticed that matplotlib.toolkits.basemap.Basemap supports a smaller
set of projection arguments than the underlying function
matplotlib.toolkits.basemap.pyproj.Proj and was wondering if there is a
fundamental limitation on the functionality of Basemap that prevents it from
handling proj arguments such as x_0, y_0, ellps, datum, and init?

I would like to be able to use all of the very nice functionality built into
Basemap on standard projections such as Oregon State Plane Coordinate
System-North NAD27 (which can be generated using pyproj.Proj with the
following proj arguments:

orspcs_m = matplotlib.toolkits.basemap.pyproj.Proj(\
proj='lcc',lat_1=44.33333333333334,lat_2=46,lat_0=43.66666666666666,\
lon_0=-120.5,x_0=609601.2192024384, y_0=0,ellps='clrk66',datum='NAD27')

or even more simply by
orspcs_m = matplotlib.toolkits.basemap.pyproj.Proj(init='epsg:32026')
or 
orspcs_m = matplotlib.toolkits.basemap.pyproj.Proj(init='nad27:3601')

but Basemap() won't accept the necessary arguments

Would this be a matter of modifying the Basemap __init__ function to
recognize a longer list of possible arguments or is there a larger issue I'm
not seeing, or a bunch more code that would require modification?

thanks,

Charles Seaton
Research Associate
OHSU/ STC-CMOP
-- 
View this message in context: http://www.nabble.com/projections-in-matplotlib.toolkits.basemap-Basemap-vs.-pyproj.Proj-tf4617163.html#a13186371
Sent from the matplotlib - users mailing list archive at Nabble.com.

I would like to use a higher resolution coastline than the high resolution
coastline optionally provided with (specifically, I would like to use the
NOAA/NOS Medium Resolution Coastline). I can see two ways to do this:

Option 1) Create a coastline file using the in the NOAA/NOS data in the same
format as the data files used by the basemap toolkit. I couldn't find a
description of this format, but it appears that it is partially explained by
the code snippet:

if line.startswith('P'):
                area = float(linesplit[5])
                west,east,south,north =
float(linesplit[6]),float(linesplit[7]),float(linesplit[8]),float(linesplit[9])
                typ = int(linesplit[3])

So the first line of the existing high resolution coastline is:
P      0  169598 1 W 79866900.000 -17.53378 190.35911 -34.83044  77.71958

Which should be interpreted as 
typ = 1
area = 79866900.000
west = -17.53378 
east = 190.35911 
south = -34.83044  
north = 77.71958

area is used to control whether this segment of coastline is displayed
the directions are the bounding box for the coastline segment
I am not clear on how typ is used (I see it getting manipulated, but I don't
see it ever getting used), or what its acceptable values are. I am also not
clear what the first, second and fourth values of the line are (not counting
the initial 'P'). Any help with this format would be appreciated.

Option 2) Load a coastline by whatever means I choose as a list of lists of
touples (or some other format?) and then transform those values using the
basemap object. If the coastline were easily expressed as a pair of lists or
arrays lon,lat, then I could simply use 

b=basemap(...) 
coastx,coasty = b(lcoastlon,coastlat)

but the coastline is made up of multiple segments (islands, etc). Is the
best way to transform a collection of segments simply to loop over the
segments?

coast = [ [(x11,y11),... (x1n,y1n)], [(x21,y21),... (x2n,y2n)],...
[(xn1,yn1),...(xnn,ynn)] ]
newcoast = []
for c in coast:
  ln,lt = map(list,zip(*c))
  x,y = m(ln,lt)
  newcoast.append(zip(x,y))

Once I have a transformed list of lists of touples, I can replace the
basemap objects coastsegs
b.coastsegs = newcoast

and then draw the coastline using the built-in 
b.drawcoastlines()

Or is there some method that I am missing?


-- 
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