[mapserver-users] No errors, but no lines on output map.

[Frank Warmerdam]

>>INFO: Open of `web/mapserv_demo/test/data/carroll'
>>using driver `TIGER' successful.
>>1: CompleteChain (Line String)
>>2: AltName (None)
>>3: FeatureIds (None)
>>4: ZipCodes (None)
>>5: Landmarks (Point)
>>6: AreaLandmarks (None)
>>7: KeyFeatures (None)
>>8: Polygon (None)
>>9: EntityNames (Point)
>>10: IDHistory (None)
>>11: PolyChainLink (None)
>>12: PIP (Point)
>>13: TLIDRange (None)
>>14: ZipPlus4 (None)
>>
>>Note:
>>When I speak of layers below, I'm talking about the argument to
>>CONNECTION in a LAYER definition.  E.g.,
>>
>>CONNECTON "data/carroll, 0"
>>
>>I have skimmed the Tiger/LINE 2000 spec (from the Census Bureau) and
>>have some understanding (perhaps wrong :) of how the different record
>>types relate.  Based on that, I thought that I should get a map of the
>>roads from layer 1 (CompleteChain).  However, the only way I get any
>>output at all is if I use 0.  If I change the layer arg to 5 and the
>>LAYER TYPE to POINT, I get nothing and the result is returned very
>>quickly unlike what happens when I use 0 which takes quite a few
>>seconds.

It is a peculiarity of the OGR integration in MapServer vs. ogrinfo that
the layer number is different.  Ogrinfo is reporting 1 based numbers while
MapServer requires zero based indexes. so CompleteChain is layer index 0.

This is noted in the OGR-HOWTO but is somewhat unobvious.

Best regards,

-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent