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I run this query:

select sdo_cs.determine_chain(null, null, 3087, 4326) from dual;

This is the result:

MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(3087,-1,4152,-2,4326))

How should I interpret the -1 and -2 in the transformation plan result? According to the docs these are operation IDs but I can't anything in SDO_COORD_OPS that matches.

A few other examples:

3087 -> 4326 via 4152

SDO_CS.DETERMINE_CHAIN(NULL,NULL,3087,4326)
MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(3087,-1,4152,-2,4326))

3087 -> 4152

SDO_CS.DETERMINE_CHAIN(NULL,NULL,3087,4152)
MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(3087,-1,4152,-2,4152))

4152 -> 4326

SDO_CS.DETERMINE_CHAIN(NULL,NULL,4152,4326)
MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(4152,-2,4326))

4326 -> 3087 via 4152

SDO_CS.DETERMINE_CHAIN(NULL,NULL,4326,3087)
MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(4326,-2,4152,-3,3087))

4326 -> 4152

SDO_CS.DETERMINE_CHAIN(NULL,NULL,4326,4152)
MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(4326,-2,4152))

4152 -> 3087

SDO_CS.DETERMINE_CHAIN(NULL,NULL,4152,3087)
MDSYS.TFM_PLAN(MDSYS.SDO_TFM_CHAIN(4152,-2,4152,-3,3087))
  • As a check convert from 3087 (ProjCRS based on NAD83 HARN) to 4152 (GeogCRS, NAD83 HARN), then convert separately to 4326. Are the output lat-lon unchanged (or only changed at the far right digit or two)? Then -1 probably means unproject from ProjCRS to GeogCRS and -2 may mean treat the two GeogCRS as equivalent. What do you get if you determin_chain on 4152, 3087? I predict a +1. – mkennedy May 19 '17 at 16:52
  • @mkennedy See examples above. The only codes I see are -1, -2, and -3. Transformation from 3087 -> 4152 is interesting because you see 4152 twice, with operations -1 and -2 chained. – nw1 May 19 '17 at 17:44
  • Okay, I officially have no idea! – mkennedy May 19 '17 at 17:46

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