'
'----------------------------
'--- Creation information ---
'----------------------------
'
'Name: pointld.ave
'Version: 1.0
'Date: 06/2/97
'Author: Ferdi Hellweger
'        Center for Research in Water Resources
'        The University of Texas at Austin
'        ferdi@crwr.utexas.edu
'
'
'---------------------------
'--- Purpose/Description ---
'---------------------------
'
'A point load grid is computed from a point, polyline and/or polygon ftheme based
'on the value in a field in the feature attribute table.
'
'--------------------
'--- User's guide ---
'--------------------
'
'1. Set the analysis cell size and extent.
'2. Highlight the input feature theme(s).  Multiple themes can processed.
'3. Run the program.
'4. Supply the field(s) holding the point load.
'
'-------------
'--- Notes ---
'-------------
'
'1. This program supports loads attached to points, polylines and polygons.
'   The loads are placed on the grid as follows:
'      Points: at the point.
'      Polylines: at the first point of the line.
'      Polygons: half way between the centroid and the first point of of the boundary.
'
'2. When using this with the CONNECT and PICKLOAD methodology the program output
'   has to be checked to see that the loads for polygons are not placed in the
'   5x5 rectangle around the centroid of the water quality segments.  If that is
'   the case the methodology for locating the load for polygons should be altered.
'
'3. The program uses a rather crude way to value the point load grid.  First a
'   point shape file is created, which is then converted to a grid with the
'   makefromftab request.  It would be much easier if cells could be valued in
'   the same as as with the ARC/INFO grid fillcell command.  An equivalent has
'   not been found in the spatial analyst.
'
'4. The output of this program is a point source load grid in the same units as
'   the load field in the input feature theme.
'
'5. The point source load grid should be added to the nonpoint source load grid
'   to create a total load grid before a weighted flow accumulation is done.
'
'----------------
'--- Get view ---
'----------------
'
theview = av.getactivedoc
'
'--------------------
'--- Get theme(s) ---
'--------------------
'
thethemes = theview.getactivethemes
if (thethemes.count = 0) then
    msgbox.error("No themes found", "POINT LOAD GRID")
    exit
end
thefthemes = list.make
for each thetheme in thethemes
    if (thetheme.getclass.getclassname = "ftheme") then
        thefthemes.add(thetheme)
    end
end
if (thefthemes.count = 0) then
    msgbox.error("No feature themes found", "POINT LOAD GRID")
    exit
end
'
'------------------------------
'--- Set up point load grid ---
'------------------------------
'
plgrid = grid.makefromnumb(0.0)
'
'------------------------
'--- Set up temp ftab ---
'------------------------
'
tempftab = ftab.makenew(("tempname").asfilename, point)
tempftab.seteditable(true)
tempshapef = tempftab.findfield("shape")
tempfields = list.make
temploadf = field.make("load", #FIELD_DECIMAL, 16, 4)
tempfields = tempfields.add(temploadf)
tempftab.addfields(tempfields)
temprec = tempftab.addrecord
'
'--------------------------
'--- Process each theme ---
'--------------------------
'
for each thetheme in thefthemes
    '
    '--- Set up theme  ---
    '
    theftab = thetheme.getftab
    theshapef = theftab.findfield("shape")
    '
    '--- Get field ---
    '
    thefields = theftab.getfields
    theloadf = msgbox.listasstring(thefields, "Choose point load field for " + thetheme.getname, "POINT LOAD GRID")
    if (theloadf = nil) then
        exit
    end
    '
    '--- Process each feature ---
    '
    for each thefeature in theftab
        'check load
        theload = theftab.returnvalue(theloadf, thefeature)
        if (theload > 0) then
            'get point
            theshape = theftab.returnvalue(theshapef, thefeature)
            if (theshape.getclass.getclassname = "point") then
                thepoint = theshape
            end
            if (theshape.getclass.getclassname = "polyline") then
                thepoint = theshape.asmultipoint.aslist.get(0)
            end
            if (theshape.getclass.getclassname = "polygon") then
                thecentroid = theshape.returncenter
                cenx = thecentroid.getx
                ceny = thecentroid.gety
                theboundarypoint = theshape.aspolyline.asmultipoint.aslist.get(0)
                boundx = theboundarypoint.getx
                boundy = theboundarypoint.gety
                pointx = ((cenx + boundx) / 2)
                pointy = ((ceny + boundy) / 2)
                thepoint = point.make(pointx, pointy)
                if (not (thepoint.iscontainedin(theshape))) then
                    msgbox.info("Point load assigned outside polygon.", "POINT LOAD GRID")
                end
            end
            'value temp ftab
            tempftab.seteditable(true)
            tempftab.setvalue(tempshapef, temprec, thepoint.clone)
            tempftab.setvalue(temploadf, temprec, theload.clone)
            tempftab.seteditable(false)
            'make temp grid
            tempgrid = grid.makefromftab(tempftab, prj.makenull, temploadf, nil)
            'add temp grid to point load grid
            plgrid = tempgrid.isnull.con(plgrid, (plgrid + tempgrid))
        end
    end
end
'
'---------------------------------
'--- Save grid and add to view ---
'---------------------------------
'
plgtheme = gtheme.make(plgrid)
theview.addtheme(plgtheme)
plgtheme.setvisible(true)
'
'-----------------------------
'--- Final message to user ---
'-----------------------------
'
message = "Point load grid calculated."
msgbox.info(message,"POINT LOAD GRID")
'
'-----------
'--- End ---
'-----------
'