' Name:  Spatial.ExtractByGraphic
' 
' Topics:  Spatial Analyst, grid extraction.
' 
' Description: This script extracts a new grid by clipping from an
' overlaying graphic. 
' 
' Requires:  Spatial Analyst Extension
' 
' Self:  
' 
' Returns:  
' 

test=Extension.Find("Spatial Analyst")
if (test=NIL) then
 msgbox.error("You must have the spatial analyst extension loaded","ExtractbyShape")
 return(nil)
end

' get the view and the selected graphics
theView = av.GetActiveDoc
theGraphics=theview.getgraphics
theSelg=theGraphics.getselected
if (theSelG.count=0) then
 msgbox.error("No Graphics Selected","ExtractbyShape")
 return(nil)
end
if (theSelG.count>1) then
 msgbox.error("More than one Graphic is Selected, just using one","ExtractbyShape")
end
agraphic=thegraphics.getselected.get(0)
if (agraphic.getshape.is(point)) then
 msgbox.error("Shape must be a line or polygon","ExtractbyShape")
 return(nil)
end
ashp=agraphic.getshape.aspolygon

' set the projection to null since graphics are projected
theprojection=Prj.MakeNull

ashpext=agraphic.getbounds
t = NIL
for each at in theView.GetActiveThemes
  if (at.Is( GTHEME )) then 
    t = at
    break
  end
end
if (t = NIL) then 
 msgbox.info("A Grid Theme needs to be active in the view", "ExtractbyShape")
 return(NIL) 
end

' Set a temporary Analysis Environment
g = t.GetGrid
Grid.SetAnalysisExtent(#GRID_ENVTYPE_VALUE, ashpext)

' Extract the grid cells base on the selected graphic
r = g.ExtractbyPolygon(ashp, theProjection, FALSE)

' rename data set
aFN = av.GetProject.GetWorkDir.MakeTmp("gext", "")
r.Rename(aFN)

' check if output is ok
if (r.HasError) then return NIL end

' create a theme 
gthm = GTheme.Make(r)  

' set name of theme
gthm.SetName("Extract from " + t.GetName)

' add theme to the specifiedView
theView.AddTheme(gthm)

gthm.invalidate(true)