| OBJ_NEW: Infinite or invalid (NaN) operands not allowed. IDL 7 vs 8 discrepancy? [message #80388] |
Thu, 07 June 2012 16:06 |
mikrin
Messages: 4
Registered: June 2012
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Junior Member |
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Hi,
I've developed some IDL object graphics code to draw the continents
onto an orthographic projection of the earth. I'm using the file
IDL_Default/resource/maps/continents.shp
Specifically I've run into issues where the code I use (see below)
works fine on IDL 8.0 running on a Mac OS X Lion system.
On IDL 7.1 running on 32bit Linux (kernel 3.0.0-19) it produces the
error,
% OBJ_NEW: Infinite or invalid (NaN) operands not allowed.
The error happens on the line (see below for code snippet)
contPoly = obj_new('IDLgrPolyline', xy, polylines=conn[1:*],
_extra=e)
if the array xy contains 1 or more NaN values then I get the error.
xy is calculated by map_proj_forward (which converts lat/lon to xy for
a given map projection). In an orthographic projection parts of some
continets are behind the visible part of the globe and thus have
undefined xy. IDL 8.0 running on my Mac seems to NOT have a problem
with this but IDL 7.1 on Linux chokes on it.
Is this an IDL 7.1 issue that was fixed on IDL 8.0 or is this a Mac/
Linux issue?
(BTW, the code also fails on Windows XP running IDL 7.1)
Mike
The specific code is:
pro drawContinentLines, MAP=map, oModel
; Use the low res continents data for now
contFilenames = filepath('continents.shp', subdir=['resource','maps/
shape'])
; Create a shape object to hold the continent lines
conts = obj_new('IDLffShape', contFilenames)
conts->getProperty, n_entities=nEntities
; Loop through all continents
for s=0L, nEntities-1L do begin
cont = conts->getEntity(s)
conn = [0]
for p=0,cont.n_parts-1L do begin
startInd = (*cont.parts)[p]
endInd = p eq cont.n_parts-1 ? cont.n_vertices : (*cont.parts)[p
+1]
conn = [conn, endInd-startInd, lindgen(endInd-startInd) +
startInd]
endfor
xy = map_proj_forward(*cont.vertices, map_structure=map)
; Create continent boundary object
contPoly = obj_new('IDLgrPolyline', xy, polylines=conn[1:*],
_extra=e)
oModel->add, contPoly
conts->destroyEntity, cont
endfor
obj_destroy, conts
end
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