NKG.sql: Add support for EUREF-FIN in Finish transformations #4399
Conversation
Recently the Finish national realization of ETRS89 was added to the EPSG
registry as it's own separate entity. This commits adds support for the
new EUREF-FIN CRS (EPSG:10689) in the NKG transformations. This is done
by duplicating the existing transformation entries for Finland and
modifying them to have EUREF-FIN as their end-point. This ensures
backwards compatibility for users that implemented the original approach
in their workflows.
The gist of it all is that in addition to the existing transformations
NKG:ITRF2000_TO_FI and NKG:ITRF2014_TO_FI
two new ones have been added:
NKG:ITRF2000_TO_FI_EUREF-FIN and NKG:ITRF2014_TO_FI_EUREF-FIN
Below a few examples are given, that verify that the old and newly added
transformations are equivalent, apart from their final target CRS.
First a demonstration of use of the transformations directly
```sh
export PROJ_DATA=data/
export PROJ_NETWORK=ON
echo 27 62 100 | bin/cct +proj=cart
2675020.1042 1362990.8210 5608603.5251 inf
echo 2675020.1042 1362990.8210 5608603.5251 2025.0 | bin/cct -d 8 NKG:ITRF2000_TO_FI
2675020.75185987 1362990.35866198 5608603.16545234 2025.0000
echo 2675020.1042 1362990.8210 5608603.5251 2025.0 | bin/cct -d 8 NKG:ITRF2000_TO_FI_EUREF-FIN
2675020.75185987 1362990.35866198 5608603.16545234 2025.0000
echo 2675020.1042 1362990.8210 5608603.5251 2025.0 | bin/cct -d 8 NKG:ITRF2014_TO_FI
2675020.76927503 1362990.36127342 5608603.12613439 2025.0000
echo 2675020.1042 1362990.8210 5608603.5251 2025.0 | bin/cct -d 8 NKG:ITRF2014_TO_FI
2675020.76927503 1362990.36127342 5608603.12613439 2025.0000
```
and then using source and target CRS's. The invovled EPSG-codes are:
```
EPSG:7912: ITRF2014 geodetic coordinates
EPSG:4937: ETRS89 geodetic coordinates
EPSG:10689: EUREF-FIN geodetic coordinates
```
```sh
echo 62 27 100 2025.0 | bin/cs2cs -d 8 EPSG:7912 EPSG:10689
61.99999528 26.99998642 99.82795259 2025
echo 62 27 100 2025.0 | bin/cs2cs -d 8 EPSG:7912 EPSG:10689 --area finland
61.99999528 26.99998642 99.82795259 2025
echo 62 27 100 2025.0 | bin/cs2cs -d 8 EPSG:7912 EPSG:4937
61.99999528 26.99998642 99.82795259 2025
echo 62 27 100 2025.0 | bin/cs2cs -d 8 EPSG:7912 EPSG:4937 --area finland
61.99999528 26.99998642 99.82795259 2025
```
As shown, the results are equivalent, which keeps existing workflows
happy.
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@phakli as promised. I believe everything works as intended but it would be good if you could verify it on your end |
data/sql/nkg.sql
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| INSERT INTO "concatenated_operation_step" ( | ||
| operation_auth_name, operation_code, step_number, step_auth_name, step_code | ||
| ) VALUES | ||
| ('NKG', 'ETRF00_TO_FI', 1, 'NKG', 'P1_2008_FI'), | ||
| ('NKG', 'ETRF00_TO_FI', 2, 'NKG', 'ETRF96_2000_TO_ETRF96_1997') | ||
| ('NKG', 'ETRF00_TO_FI', 2, 'NKG', 'ETRF96_2000_TO_ETRF96_1997'), |
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would you mind adding the new optional step_direction column with 'forward' / 'reverse' value ? (same remark for below occurences)
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more a matter of presentation / taste, but I would probably use a INSERT INTO "concatenated_operation_step" per concatenated operation. My first reading of the pull request change was that it became a 4-step operation, before realizing it was 2 concatenated operations in the same statement. Same remark for below occurences
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I've added the direction hints to entries in the `concatenated_operation_step" table. There is a good mix of forward and reverse in there, so it should be a bit more efficient now with them directions added.
I can see how that is a bit misleading but seeing as the operation codes are different in lenghts I think is fairly clear that they are different:
('NKG', 'ETRF00_TO_FI', 1, 'NKG', 'P1_2008_FI', 'forward'),
('NKG', 'ETRF00_TO_FI', 2, 'NKG', 'ETRF96_2000_TO_ETRF96_1997', 'forward'),
('NKG', 'ETRF00_TO_EUREF-FIN', 1, 'NKG', 'P1_2008_FI', 'forward'),
('NKG', 'ETRF00_TO_EUREF-FIN', 2, 'NKG', 'ETRF96_2000_TO_ETRF96_1997_EUREF-FIN', 'forward')
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Thanks a lot @kbevers! It looks good to me and I can also confirm from my side that it produces expected results.
Recently the Finish national realization of ETRS89 was added to the EPSG registry as it's own separate entity. This commits adds support for the new EUREF-FIN CRS (EPSG:10689) in the NKG transformations. This is done by duplicating the existing transformation entries for Finland and modifying them to have EUREF-FIN as their end-point. This ensures backwards compatibility for users that implemented the original approach in their workflows.
The gist of it all is that in addition to the existing transformations
two new ones have been added:
Below a few examples are given, that verify that the old and newly added transformations are equivalent, apart from their final target CRS.
First a demonstration of use of the transformations directly
and then using source and target CRS's. The invovled EPSG-codes are:
As shown, the results are equivalent, which keeps existing workflows happy.