'
'----------------------------
'--- Creation information ---
'----------------------------
'
'Name: pickgrid.ave
'Version: 1.0
'Date: 03/01/97
'Author: Ferdi Hellweger
'        Center for Research in Water Resources
'        The University of Texas at Austin
'        ferdi@crwr.utexas.edu
'
'---------------------------
'--- Purpose/Description ---
'---------------------------
'
'This program picks up the value from a grid at the centroid of the polygon and
'writes it to the specified field in the polygon attribute table.
'
'----------------
'--- Get view ---
'----------------
'
theview = av.getactivedoc
vgraphics = theview.getgraphics
'
'------------------
'--- Get themes ---
'------------------
'
theactivethemes = theview.getactivethemes
if (theactivethemes.count = 0) then
    msgbox.error("No active themes found", "BALANCE")
    exit
end
if (theactivethemes.count = 1) then
    msgbox.error("Only one active theme found", "BALANCE")
    exit
end
if (theactivethemes.count > 2) then
    msgbox.error("Too many active themes found", "BALANCE")
    exit
end
if (theactivethemes.count = 2) then
    gfound = false
    pfound = false
    for each activetheme in theactivethemes
        if (activetheme.getclass.getclassname = "gtheme") then
            thegtheme = activetheme
            gfound = true
        end
        if (activetheme.getclass.getclassname = "ftheme") then
            theptheme = activetheme
            pfound = true
        end
    end
end
if (not gfound) then
    msgbox.error("One theme needs to be a grid theme", "BALANCE")
    exit
end
if (not pfound) then
    msgbox.error("One theme needs to be a polygon theme", "BALANCE")
    exit
end
'
'---------------------
'--- Set up themes ---
'---------------------
'
'grid theme
'
thegrid = thegtheme.getgrid
'
'check below causes error crash for some reason
'
'if (thegrid = nil) then
'    msgbox.error("Can't open grid theme","BALANCE")
'    exit 
'end
thecellsize = thegrid.getcellsize
'
'polygon theme
'
pftab = theptheme.getftab
if (pftab = nil) then
    msgbox.error("Can't open polygon theme","BALANCE")
    exit
end
'
pshapef = pftab.findfield("shape")
if (pshapef = nil) then
    msgbox.error("Can't find 'shape' field in polygon theme","BALANCE")
    exit
end
'
pfields = pftab.getfields
pvaluef = msgbox.listasstring(pfields, "Field to write to:", "BALANCE")
if (pvaluef = nil) then
    exit
end
'
'-----------------
'--- Calculate ---
'-----------------
'
'--- Initial set up ---
'
'make polygon attribute table editable
'
pftab.seteditable(true)
'
'--- Loop ---
'
for each prec in pftab
    '
    'get centroid
    '
    pshape = pftab.returnvalue(pshapef, prec)
    cenp = pshape.returncenter
    '
    'plot centroid
    '
    cengs = graphicshape.make(cenp)
    vgraphics.add(cengs)
    '
    'check if centroid is in polygon
    '
    inside = cenp.iscontainedin(pshape)
    if (not inside) then
        msgbox.error("Polygon centroid not inside polygon", "BALANCE")
    end
    '
    'get value
    '
    val = thegtheme.returncellvalue(cenp)
    '
    'write value to polygon attribute table
    '
    pftab.setvalue(pvaluef, prec, val)
    '
end
'
'make polygon attribute table non editable
'
pftab.seteditable(false)
'
'final message to user
'
message = "Grid value picked"
msgbox.info(message,"BALANCE")
'
'-----------
'--- End ---
'-----------
'