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Blob field in SQL Server to usable Geometry

  • September 26, 2019
  • 6 replies
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Hello, I have a BLOB field, it is supposedly multiple points that form a polyline, but I cannot export the blob into a usable geometry. I have tried GeometryReplacer and GeometryExtractor but I have not been able to get usable results. I attached an excel file with the BLOBs

Best answer by david_r

The only way I was able to get the GeometryReplacer to return anything else than an error was by first removing the "0x" prefix and treat it like a QlikMaps Encoded Polyline. However the result doesn't make much sense (to me):

I think the key here is to know how the geometry is encoded in the blob, or at the very least know which software is used to manipulate it.

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6 replies

daveatsafe
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  • 1637 replies
  • September 26, 2019

Hi @morijlumos,

Do you know what format the BLOB geometry is in?


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  • Author
  • 22 replies
  • September 26, 2019

Hi @morijlumos,

Do you know what format the BLOB geometry is in?

It is varbinary(max)


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  • Author
  • 22 replies
  • September 26, 2019

Hi @morijlumos,

Do you know what format the BLOB geometry is in?

I am fairly certain it is supposed to be points


daveatsafe
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  • 1637 replies
  • September 26, 2019

I am fairly certain it is supposed to be points

From that info, it appears to be a set of points in each record, but the key thing to know is how is it binary encoded. The GeometryReplacer in FME supports several kinds of binary geometries: FME Binary (likely not the case), OGC WKB and SQL Server Binary. I have tried all those, and none of them seem to be the encoding used.


david_r
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  • 8394 replies
  • Best Answer
  • September 27, 2019

The only way I was able to get the GeometryReplacer to return anything else than an error was by first removing the "0x" prefix and treat it like a QlikMaps Encoded Polyline. However the result doesn't make much sense (to me):

I think the key here is to know how the geometry is encoded in the blob, or at the very least know which software is used to manipulate it.


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  • Author
  • 22 replies
  • September 27, 2019

Thanks! It looks like after all that there doesn't seem to be much useable data in there at all, or its something that ESRI doesn't want to show us!