Lesson4 VCS_XmGrace_CDAT_Graphics

8/6/2019 Lesson4 VCS_XmGrace_CDAT_Graphics

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Lesson4

Visualization vcs andxmgrace


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Preview

VisualizationandControlSystem(VCS)

Xmgrace


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VCSConceptsandTerminology

Basicconcepts:

VCSCanvas where

the

plots

are

drawn GraphicMethods howthedataisrendered(the

plottype).E.g.boxfill,isofill,isoline,

vector,

etc,.

Multiple

projectionsmay

be

availableforagivenGraphicMethod.

Templates definethelocationwherethingsare

drawn

on

the

canvas

(data,

legend,

title,

comments,units,etc..)

Primitives additionalsecondaryitemssuchaslines,polygons,text,markers,etc.,


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TheVCSCanvas

VCScanvasneedstobeinitialized(created)

>>> x=vcs.init() # without any arguments

Upto8Canvasesatonce.

Canvasasmagicboard,cancleanordestroyit:>>> x.clear()

>>> x.close()

CanhavemultipleplotsonasingleCanvas(notcoveredhere)


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VCSHelp

BasichelponVCScanbeobtaininlinevia:>>>vcs.help()

Thiswilllistavailablefunctionin VCS,notablyfunctionstocreate/get/query VCSobjects


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VCSFirstHelp

Thisalsocanbeusedtogethelponaspecific

command:>>> vcs.help(createboxfill)

Function: createboxfill# Construct a new boxfill graphics method

Description of Function:Createanewboxfill graphicsmethodgiventhenameandtheexistingboxfill

graphicsmethodtocopythe attributesfrom.Ifnoexistingboxfill graphicsmethodnameisgiven,thenthedefaultboxfill graphicsmethodwillbeusedasthegraphicsmethodtowhichtheattributeswillbecopiedfrom.

Ifthenameprovidedalreadyexists,thenaerrorwillbereturned.Graphics

methodnamesmustbeunique.


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GraphicMethodsConcepts(1)

EssentiallyagraphicmethodrepresentsHOWdataaregoingtobeplotted(theWHEREwillbedeterminedviatemplates,seelater)

Thereare13typeofgraphicmethodsinVCS: 2DGraphicMethods

Boxfill,Isofill,Isoline,Meshfill,Vector,Outfill,

Outline,

Continents

, (Taylordiagrams)

1DGraphicMethods

Yxvsx,

Xyvsy,

XvsY,

Scatter


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SpecifyingaGraphicMethod

Tospecifyagraphicmethoduseacreatefunction,thenuseplot:

Forexample,foraboxfill:

>>> gm = x.createboxfill(name)

>>> x.plot(data, gm)

Ifagraphicmethodalreadyexists,usegetfunctions:

>>> gm = x.getboxfill(name)

>>> x.plot(data, gm)

Replaceboxfillintheaboveforothermethods.


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2D boxfill

Theboxfill graphicmethodtakesa2Darrayandrepresentsit

byfillingabox(determinedbytheboundsoneachaxis

values)withacolor linkedtothearraysvalueatthislocation:

>>> box=x.createboxfill(new)

>>> x.plot(data,box)


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2D isofill

Isofill graphicmethodsdrawsfilledisocontour

Theyareextremelysimilartoboxfill customtype

KnownLimitation:

Nocontrolonlabelsposition

Nocontrolonisolines Smoothness

>>> iso=x.createisofill(new)


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2D isoline

Isoline,drawsisocontours,color,style,canbe

controlled. Limitation:

No

control

on

the

labels

location Nocontrolofsmoothness

>>> iso=x.createisoline(new)


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2D vector

TheVectorgraphicmethodrepresentsthe

combinationof2arrays,viavectorthefirst

arrayrepresentingtheXaxiscomponent

andthesecondarrayrepresentingtheY

axiscomponent.>>> f=cdms.open(sample_data/clt.bc)

>>> u=f(u)

>>> v=f(v)

>>> vec=x.createvector(new)

>>> x.plot(u,v,vec)


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1D Y(x)vs x

All1DplotsinVCSbasicallyworkthesameway.Thereare4typesof1Dgraphicmethod,wellstartwiththebasic:Yxvsx,whichstandsforY(x)vsx

Thisgraphicmethoddrawsa1Darray(Y)asafunctionofits1Daxis(x)

Examplezonalmeanofthefirsttimepointofourdataarray>>> zm=MV.average(data[0],1) # Zm.shape is (46,)

>>> x.plot(zm) # knows to plot 1D with yxvsx

>>> yx=x.createyxvsx(new)

>>> x.plot(zm,yx) # same


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1D VCSYxvsxattributes

Asinisoline,orvector,line,linecolor,

linewidth,determinetheline. marker,markercolor,markersize,determine

the

markers

to

be

drawn:>>> yx.line='dot'>>> yx.linecolor=242

>>> yx.linewidth=2

>>> yx.marker='star

>>> yx.markercolor=244


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GraphicMethodsAttributes

>>> b=x.createboxfill(new_one)

>>> b.list()

Boxfill (Gfb)member(attribute)listings

CanvasMode=1

graphicsmethod=Gfb #indicatesthegraphicmethodtype:GraphicFilledBoxes(Gfb)

name=new #Nameofthespecificgraphicmethod

projection=linear#projectiontouse(seeprojectionsection)

xticlabels1=* #1stsetofticlabels,* meansautomatic

xticlabels2=*#2ndsetoflabels(posdeterminedbytemplate)

xmtics1= #1stsetofsubti fordetails)xmtics2=

yticlabels1=*


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2D WorldCoordinates example

attributes worldcoordinate attributesarepresentonall

graphic

methods. canselectasubsetarea.

forexampletovisualiseAfrica:

>>> b.datawc_x1 = -45.

>>> b.datawc_x2 = 70.

>>> b.datawc_y1 = -38.

>>> b.datawc_y2 = 38.

>>> x.plot(s,b)


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Projections

P=x.createprojection()

Graphicmethod.projection=P

P.type=n

Ncanbeoneof28possible

printP.__doc__

Eachtypehasspecificparameters

P.list()

importvcs,cdms2,sys

f=cdms2.open(sys.prefix+\

/sample_data/clt.nc)

s=f(clt,time=slice(0,1),\

longitude=(210,50))

x=vcs.init()

iso=x.createisofill()

p=x.createprojection()

p.type=orthographic

iso.projection=p

x.plot(s,iso,ratio=1t)

x.clear()

p.type=lambert

x.plot(s(latitude=(20,70),\

longitude=(150,50)),iso)


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ProjectionattributesofGraphic

MethodsEachgraphicmethodmayhaveanumberof

projections,thefulllistisavailablefrom:>>> v.show('projection')************************Projection Names List*************************

( 1): default linear mollweide

( 4): robinson polyconic polar( 7): lambert orthographic mercator

************************End Projection Names List*********************

mollweide polar robinson


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VCS:templatemanipulation

TemplateratioX.ratio=2 : y is twice as big as x

X.ratio=autoX.ratio=2t : also moves tick marks

Templatescaling(lowerleftdataareaunchanged)T.scale(.5) # half size

T.scale(.5, axis=x) #half size in X, fontunchanged

T.scale(.5, axis=x, font=1) # also alterfonts

TemplatemovingT.move(.2, .4) # move by 20% in x, 40% in yPositive values means up/right

T.moveto(x,y) # move lower left corner ofdata to x,y


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VCS:templatemanipulation

UsingEzTemplate

Alsoavailable:EzTemplate.oneD,

for1Dplots,usestheprovidedbasetemplateandmovethelegendaccordingtothenumberofdataset

fromvcsaddons importEzTemplate

importvcs

x=vcs.init()

M=EzTemplate.Multi(rows=4,columns=3)

fori inrange(12):

t=M.get()x.plot(s,t,iso)

OD=EzTemplate.oneD(n=n,template=t)

fori inrange(n):

y =MV2.sin((i+1)*x)y.setAxis(0,ax)

yx =X.createyxvsx()

yx.linecolor=241+i

yx.datawc_y1=1.

yx.datawc_y2=1.t =OD.get()

X.plot(y,t,yx,bg=bg)


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vcs:textprimitives

text=x.createtext()TextTable(Tt)member(attribute)listings

Tt_name =newfont=1spacing=2

expansion=100color=1priority=1string=Noneviewport=[0,1,0,1]worldcoordinate =[0,1,0,1]x =Noney =None

projection=defaultTextOrientation(To)member(attribute)listings

To_name =newheight=14angle=0path=righthalign =leftvalign =half

Font_name =x.addfont(path_to_ttf_font)

Font=x.getfont(Font_name)#usableintemplate

Availablefontsbydefault:['Adelon','Arabic','AvantGarde','Chinese','Clarendon','Courier','Greek','Hebrew','Helvetica','Maths1','Maths2','Maths3','Maths4','Russian','Times','default']


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vcs:otherprimitives

fa=x.createfillarea(new)

l=x.createline(new)

m=x.createmarker(new)

Eachprimitivehasthe2followingattributes: Prim.viewport=[xv1,xv2,yv1,yv2]#default:[0,1,0,1]

In%ofpage,areaoftheprimitiveextends

Prim.worldcoordinates =[x1,x2,y1,y2]#defalut [0,1,0,1] Coordinatescorrespondingtoxv1,xv2,yv1,yv2

Primitiveunitsareintheworldcoordinate system

Example text.viewport=[.25,.75,.25,.75]#definesmallerzoneonpage

text.worldcoordinate=[180, 90,180,90]#Definethecoordinatesystem

text.x=[122.4428]

text.y=[37.7709]

text.string=[SanFrancisco,CA,94117]

Foroverlaywithanexistinggraphicmethod Prim.viewport #settoyourtemplate.data

Prim.worldcoordinates #settoyourgraphicmethod.data.wc


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Animating throughtheGUI


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Animatingatthecommandline

Justkeepwriteaframetoacanvas,togifand

clear,thendoalloveragain>>> x=vcs.init()

>>> templ=canvas.gettemplate('BADC_ERA40')

>>> plot_type=canvas.getisofill(ASD)

>>> for i in range(loop_num):

... x.clear()

... x.plot( data( time=slice(i,i+1) ), templ, \plot_type)

... x.gif(outfile) # Second arg of merge="a"

# needed on some versions

OrcallupGUIwithx.animate.gui()


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Example:VCS

Lookatthesampleprogramtest_vcs.pyand

runitthroughstepbystep.


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vcsaddons

GIScapability.Youcanreadandplotgis/shapefiles.

importvcs,vcsaddons

importcdms2,sysx=vcs.init()

importvcs.test.support

bg=0

c=vcsaddons.createusercontinents(x=x)

lon1=

125lon2=75.

lat1=20.

lat2=55.

c.types =['shapefile','shapefile']

c.sources =['../Data/co1990p020','../Data/fe_2007_06_county',]

c.colors =[246,241,244,241]c.widths=[1,1,1]

c.lines=['solid','solid','solid','dot']

f=cdms2.open(sys.prefix+/sample_data/clt.nc)

s=f("clt",latitude=(lat1,lat2),longitude=(lon1,lon2),time=slice(0,1

))

t=x.createtemplate()

iso=x.createisofill()

x.plot(s,t,iso,continents=0,ratio='autot',bg=bg)

x.plot(s,c,t,ratio='autot',bg=bg)

x.png('uscounties')

importvcsaddons._gis

sources=

['../Data/fe_2007_06_county.dbf','../Dat

a/co1990p020.dbf]

fors insources:

D=vcsaddons._gis.readdbffile(s)

printD.keys()

try:

printD['NAME']

except:

printD['COUNTY']


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Xmgrace

Xmgrace isaveryniceplottingpackage for

1ddata. Ifyouhavexmgrace installedonyour

computer,

you

can

script

it

via

CDAT.

Its

interfacehasbeenmappedtobeascloseas

possiblefromtheparameterfilesfrom

xmgrace.


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Example:Xmgrace

Lookatthesampleprogram

test_xmgrace.pyandrunitthroughstepbystep.


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Otherpackages

Matplotlib:http://matplotlib.sourceforge.net

Visus

IaGraphics
http://matplotlib.sourceforge.net/http://matplotlib.sourceforge.net/


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Acknowledgements

DeanWilliams,CharlesDoutriaux (PCMDI,

LLNL) Dr.JohnnyLin

Documents

Lesson4 VCS_XmGrace_CDAT_Graphics