ちゃんと原典となるデータを見ておきたいと長いこと思っていたのですが、ようやく少しまとまった時間が取れたので、眺めてみました。EPSGデータです。
EPSGのデータは、こちらからダウンロードできます。今回は 12.005データを。
https://epsg.org/download-dataset.html
諸RDBMSへとインポート（登録）するためのスクリプトが提供されているので、今回はMySQL用のものをダウンロードして、登録してみました。
ざっくりテーブル構造はこんな感じ。意外とでかい。
今回の目的は、MySQLの ST_SPATIAL_REFERENCE_SYSTEMSに登録されている値がどこから来ているのかを把握すること。↓の値です。
mysql> SELECT * FROM information_schema.st_spatial_reference_systems WHERE SRS_ID=6668; +----------+--------+--------------+--------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+ | SRS_NAME | SRS_ID | ORGANIZATION | ORGANIZATION_COORDSYS_ID | DEFINITION | DESCRIPTION | +----------+--------+--------------+--------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+ | JGD2011 | 6668 | EPSG | 6668 | GEOGCS["JGD2011",DATUM["Japanese Geodetic Datum 2011",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","1128"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.017453292519943278,AUTHORITY["EPSG","9122"]],AXIS["Lat",NORTH],AXIS["Lon",EAST],AUTHORITY["EPSG","6668"]] | NULL | +----------+--------+--------------+--------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+ 1 row in set (0.00 sec)
とりあえずデータを見る
ひとつひとつテーブルを見ながらデータを追ったり確認したりという地道な経過はすべて省略して、とりあえずこんなクエリでざっくりとデータを確認するところにたどり着いたところから。
SELECT cfs.coord_ref_sys_code, cfs.coord_ref_sys_name, cfs.area_of_use_code, cfs.coord_ref_sys_kind, cfs.coord_sys_code, cfs.datum_code, cfs.base_crs_code, cfs.projection_conv_code, cfs.remarks, cfs.information_source, cfs.data_source, cfs.revision_date, cfs.change_id, cfs.deprecated, cfs.show_crs, cs.coord_sys_name, cs.coord_sys_type, cs.dimension, cs.remarks, cs.information_source, cs.data_source, cs.revision_date, cs.change_id, cs.deprecated, d.datum_name, d.datum_type, d.origin_description, d.realization_epoch, d.ellipsoid_code, d.prime_meridian_code, d.remarks, d.information_source, d.data_source, d.revision_date, d.change_id, d.deprecated, d.conventional_rs_code, d.publication_date, d.frame_reference_epoch, d.realization_method_code, d.anchor_epoch, el.ellipsoid_name, el.semi_major_axis, el.uom_code, el.inv_flattening, el.semi_minor_axis, el.ellipsoid_shape, el.remarks, el.information_source, el.data_source, el.revision_date, el.change_id, el.deprecated, pm.prime_meridian_name, pm.greenwich_longitude, pm.uom_code, pm.remarks, pm.information_source, pm.data_source, pm.revision_date, pm.change_id, pm.deprecated, co1.coord_op_code co1_coord_op_code, co1.coord_op_name, co1.coord_op_type, co1.source_crs_code, co1.target_crs_code, co1.coord_tfm_version, co1.coord_op_variant, co1.area_of_use_code, co1.coord_op_scope, co1.coord_op_accuracy, co1.coord_op_method_code, co1.uom_code_source_coord_diff, co1.uom_code_target_coord_diff, co1.remarks, co1.information_source, co1.data_source, co1.revision_date, co1.change_id, co1.show_operation, co1.deprecated, co2.coord_op_code co2_coord_op_code, co2.coord_op_name, co2.coord_op_type, co2.source_crs_code, co2.target_crs_code, co2.coord_tfm_version, co2.coord_op_variant, co2.area_of_use_code, co2.coord_op_scope, co2.coord_op_accuracy, co2.coord_op_method_code, co2.uom_code_source_coord_diff, co2.uom_code_target_coord_diff, co2.remarks, co2.information_source, co2.data_source, co2.revision_date, co2.change_id, co2.show_operation, co2.deprecated -- ,copv.coord_op_code, copv.coord_op_method_code, copv.parameter_code, copv.parameter_value, copv.param_value_file_ref, copv.uom_code, -- ,copu.coord_op_method_code, copu.parameter_code, copu.sort_order, copu.param_sign_reversal -- ,ca.coord_axis_code, ca.coord_sys_code, ca.coord_axis_name_code, ca.coord_axis_orientation, ca.coord_axis_abbreviation, ca.uom_code, ca.coord_axis_order FROM epsg_coordinatereferencesystem cfs LEFT OUTER JOIN epsg_coordinatesystem cs ON (cfs.coord_sys_code=cs.coord_sys_code) LEFT OUTER JOIN epsg_datum d ON (cfs.datum_code=d.datum_code) LEFT OUTER JOIN epsg_ellipsoid el ON (d.ellipsoid_code=el.ellipsoid_code) LEFT OUTER JOIN epsg_primemeridian pm ON (d.prime_meridian_code=pm.prime_meridian_code) LEFT OUTER JOIN epsg_coordoperation co1 ON (cfs.coord_ref_sys_code=co1.source_crs_code) LEFT OUTER JOIN epsg_coordoperation co2 ON (cfs.coord_ref_sys_code=co1.target_crs_code) -- LEFT OUTER JOIN epsg_coordinateaxis ca ON (cs.coord_sys_code=ca.coord_sys_code) -- LEFT OUTER JOIN epsg_coordoperationparamvalue copv ON (co1.coord_op_code=copv.coord_op_code OR co2.coord_op_code=copv.coord_op_code) -- LEFT OUTER JOIN epsg_coordoperationparamusage copu ON (copv.coord_op_method_code=copu.coord_op_method_code) WHERE cfs.coord_ref_sys_code='6668'\G
結果はこれ。何やら JGD2011(地理座標)について色々な情報が得られました。
*************************** 1. row ***************************
coord_ref_sys_code: 6668
coord_ref_sys_name: JGD2011
area_of_use_code: NULL
coord_ref_sys_kind: geographic 2D
coord_sys_code: 6422
datum_code: 1128
base_crs_code: 6667
projection_conv_code: 15593
remarks: Replaces JGD2000 (CRS code 4612) with effect from 21st October 2011.
information_source: EPSG. See 3D CRS for original information source.
data_source: EPSG
revision_date: 2019-07-17
change_id: 2013.063 2019.036
deprecated: 0
show_crs: 1
coord_sys_name: Ellipsoidal 2D CS. Axes: latitude, longitude. Orientations: north, east. UoM: degree
coord_sys_type: ellipsoidal
dimension: 2
remarks: Coordinates referenced to this CS are in degrees. Any degree representation (e.g. DMSH, decimal, etc.) may be used but that used must be declared for the user by the supplier of data. Used in geographic 2D coordinate reference systems.
information_source: OGP
data_source: EPSG
revision_date: 2015-05-22
change_id: 2008.045 2015.018
deprecated: 0
datum_name: Japanese Geodetic Datum 2011
datum_type: geodetic
origin_description: ITRF94 at epoch 1997.0 except for northern Honshu area impacted by 2011 Tohoku earthquake which is ITRF2008 at epoch 2011.395. Fundamental point: Tokyo-Taisho, latitude: 35°39'29.1572"N, longitude: 139°44'28.8869"E (of Greenwich).
realization_epoch:
ellipsoid_code: 7019
prime_meridian_code: 8901
remarks: Instigated under amendment to the Japanese Surveying Law with effect from 21st October 2011. Replaces JGD2000 (datum code 6612).
information_source: Geodetic Department, Geospatial Information Authority of Japan (GSI).
data_source: EPSG
revision_date: 2013-12-15
change_id: 2013.063
deprecated: 0
conventional_rs_code: NULL
publication_date: 2011-10-21
frame_reference_epoch: NULL
realization_method_code: NULL
anchor_epoch: NULL
ellipsoid_name: GRS 1980
semi_major_axis: 6378137
uom_code: 9001
inv_flattening: 298.257222101
semi_minor_axis: NULL
ellipsoid_shape: 1
remarks: Adopted by IUGG 1979 Canberra. Inverse flattening is derived from geocentric gravitational constant GM = 3986005e8 m*m*m/s/s; dynamic form factor J2 = 108263e-8 and Earth's angular velocity = 7292115e-11 rad/s.
information_source: "Geodetic Reference System 1980" by H. Moritz; Bulletin Geodesique
data_source: EPSG
revision_date: 2013-08-23
change_id: 1998.110 1998.320 2013.043
deprecated: 0
prime_meridian_name: Greenwich
greenwich_longitude: 0
uom_code: 9102
remarks: The international reference meridian as defined first by the 1884 International Meridian Conference and later by the Bureau International de l'Heure (BIH) and then the International Earth Rotation Service (IERS).
information_source: OGP
data_source: EPSG
revision_date: 2016-12-15
change_id: 1996.290 2016.045
deprecated: 0
co1_coord_op_code: 9936
coord_op_name: JGD2011 to WGS 84 (1)
coord_op_type: transformation
source_crs_code: 6668
target_crs_code: 4326
coord_tfm_version: EPSG-Jpn
coord_op_variant: 1
area_of_use_code: NULL
coord_op_scope:
coord_op_accuracy: 1
coord_op_method_code: 9603
uom_code_source_coord_diff: NULL
uom_code_target_coord_diff: NULL
remarks:
information_source: IOGP
data_source: EPSG
revision_date: 2021-12-30
change_id: 2021.116
show_operation: 1
deprecated: 0
co2_coord_op_code: NULL
coord_op_name: NULL
coord_op_type: NULL
source_crs_code: NULL
target_crs_code: NULL
coord_tfm_version: NULL
coord_op_variant: NULL
area_of_use_code: NULL
coord_op_scope: NULL
coord_op_accuracy: NULL
coord_op_method_code: NULL
uom_code_source_coord_diff: NULL
uom_code_target_coord_diff: NULL
remarks: NULL
information_source: NULL
data_source: NULL
revision_date: NULL
change_id: NULL
show_operation: NULL
deprecated: NULL
1 row in set (0.02 sec)
AXIS情報
AXISの情報は次元2つなので複数データになってしまうので、上とは別のクエリで取得。LATとLONの順序について定義されており、なにやら色々名コードが付随しています。
mysql> SELECT cfs.coord_ref_sys_code,
-> ca.coord_axis_code, ca.coord_sys_code, ca.coord_axis_name_code, ca.coord_axis_orientation, ca.coord_axis_abbreviation, ca.uom_code, ca.coord_axis_order
-> ,uom.uom_code, uom.unit_of_meas_name, uom.unit_of_meas_type, uom.target_uom_code, uom.factor_b, uom.factor_c, uom.remarks, uom.information_source, uom.data_source, uom.revision_date, uom.change_id, uom.deprecated
-> FROM epsg_coordinatereferencesystem cfs
-> LEFT OUTER JOIN epsg_coordinateaxis ca ON (cfs.coord_sys_code=ca.coord_sys_code)
-> LEFT OUTER JOIN epsg_unitofmeasure uom ON (ca.uom_code=uom.uom_code)
-> WHERE cfs.coord_ref_sys_code='6668';
+--------------------+-----------------+----------------+----------------------+------------------------+-------------------------+----------+------------------+----------+--------------------------------------------+-------------------+-----------------+------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------+--------------------+-------------+---------------+-----------+------------+
| coord_ref_sys_code | coord_axis_code | coord_sys_code | coord_axis_name_code | coord_axis_orientation | coord_axis_abbreviation | uom_code | coord_axis_order | uom_code | unit_of_meas_name | unit_of_meas_type | target_uom_code | factor_b | factor_c | remarks | information_source | data_source | revision_date | change_id | deprecated |
+--------------------+-----------------+----------------+----------------------+------------------------+-------------------------+----------+------------------+----------+--------------------------------------------+-------------------+-----------------+------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------+--------------------+-------------+---------------+-----------+------------+
| 6668 | 106 | 6422 | 9901 | north | Lat | 9122 | 1 | 9122 | degree (supplier to define representation) | angle | 9101 | 3.14159265358979 | 180 | = pi/180 radians. The degree representation (e.g. decimal, DMSH, etc.) must be clarified by suppliers of data associated with this code. | OGP | EPSG | 2015-11-25 | 2015.062 | 0 |
| 6668 | 107 | 6422 | 9902 | east | Lon | 9122 | 2 | 9122 | degree (supplier to define representation) | angle | 9101 | 3.14159265358979 | 180 | = pi/180 radians. The degree representation (e.g. decimal, DMSH, etc.) must be clarified by suppliers of data associated with this code. | OGP | EPSG | 2015-11-25 | 2015.062 | 0 |
+--------------------+-----------------+----------------+----------------------+------------------------+-------------------------+----------+------------------+----------+--------------------------------------------+-------------------+-----------------+------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------+--------------------+-------------+---------------+-----------+------------+
2 rows in set (0.00 sec)縦表示にするなら、こう。
*************************** 1. row ***************************
coord_ref_sys_code: 6668
coord_axis_code: 106
coord_sys_code: 6422
coord_axis_name_code: 9901
coord_axis_orientation: north
coord_axis_abbreviation: Lat
uom_code: 9122
coord_axis_order: 1
uom_code: 9122
unit_of_meas_name: degree (supplier to define representation)
unit_of_meas_type: angle
target_uom_code: 9101
factor_b: 3.14159265358979
factor_c: 180
remarks: = pi/180 radians. The degree representation (e.g. decimal, DMSH, etc.) must be clarified by suppliers of data associated with this code.
information_source: OGP
data_source: EPSG
revision_date: 2015-11-25
change_id: 2015.062
deprecated: 0
*************************** 2. row ***************************
coord_ref_sys_code: 6668
coord_axis_code: 107
coord_sys_code: 6422
coord_axis_name_code: 9902
coord_axis_orientation: east
coord_axis_abbreviation: Lon
uom_code: 9122
coord_axis_order: 2
uom_code: 9122
unit_of_meas_name: degree (supplier to define representation)
unit_of_meas_type: angle
target_uom_code: 9101
factor_b: 3.14159265358979
factor_c: 180
remarks: = pi/180 radians. The degree representation (e.g. decimal, DMSH, etc.) must be clarified by suppliers of data associated with this code.
information_source: OGP
data_source: EPSG
revision_date: 2015-11-25
change_id: 2015.062
deprecated: 0
2 rows in set (0.00 sec)
その他のパラメタ
その他の値について、今回使いそうなものを取得しておきます。途中の横線は私が見やすいように追加したものです。
mysql> SELECT cfs.coord_ref_sys_code, co1.source_crs_code, co1.target_crs_code
-> ,copv.coord_op_code, copv.coord_op_method_code, copv.parameter_code, copv.parameter_value, copv.param_value_file_ref, copv.uom_code
-> ,copu.coord_op_method_code, copu.parameter_code, copu.sort_order, copu.param_sign_reversal
-> FROM epsg_coordinatereferencesystem cfs
-> LEFT OUTER JOIN epsg_coordoperation co1 ON (cfs.coord_ref_sys_code=co1.source_crs_code OR cfs.coord_ref_sys_code=co1.target_crs_code)
-> LEFT OUTER JOIN epsg_coordoperationparamvalue copv ON (co1.coord_op_code=copv.coord_op_code AND co1.coord_op_method_code=copv.coord_op_method_code)
-> LEFT OUTER JOIN epsg_coordoperationparamusage copu ON (copv.coord_op_method_code=copu.coord_op_method_code AND copv.parameter_code=copu.parameter_code)
-> WHERE cfs.coord_ref_sys_code='6668';
+--------------------+-----------------+-----------------+---------------+----------------------+----------------+-----------------+-----------------------------+----------+----------------------+----------------+------------+---------------------+
| coord_ref_sys_code | source_crs_code | target_crs_code | coord_op_code | coord_op_method_code | parameter_code | parameter_value | param_value_file_ref | uom_code | coord_op_method_code | parameter_code | sort_order | param_sign_reversal |
+--------------------+-----------------+-----------------+---------------+----------------------+----------------+-----------------+-----------------------------+----------+----------------------+----------------+------------+---------------------+
| 6668 | 4612 | 6668 | 6698 | 9603 | 8605 | 0 | | 9001 | 9603 | 8605 | 1 | Yes |
| 6668 | 4612 | 6668 | 6698 | 9603 | 8606 | 0 | | 9001 | 9603 | 8606 | 2 | Yes |
| 6668 | 4612 | 6668 | 6698 | 9603 | 8607 | 0 | | 9001 | 9603 | 8607 | 3 | Yes |
| 6668 | 4612 | 6668 | 6713 | 9615 | 8656 | NULL | touhokutaiheiyouoki2011.gsb | NULL | 9615 | 8656 | 1 | Yes |
+--------------------+-----------------+-----------------+---------------+----------------------+----------------+-----------------+-----------------------------+----------+----------------------+----------------+------------+---------------------+
| 6668 | 4301 | 6668 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
| 6668 | 4301 | 6668 | 6740 | 9615 | 8656 | NULL | tky2jgd.gsb | NULL | 9615 | 8656 | 1 | Yes |
+--------------------+-----------------+-----------------+---------------+----------------------+----------------+-----------------+-----------------------------+----------+----------------------+----------------+------------+---------------------+
| 6668 | 6668 | 4326 | 9936 | 9603 | 8605 | 0 | | 9001 | 9603 | 8605 | 1 | Yes |
| 6668 | 6668 | 4326 | 9936 | 9603 | 8606 | 0 | | 9001 | 9603 | 8606 | 2 | Yes |
| 6668 | 6668 | 4326 | 9936 | 9603 | 8607 | 0 | | 9001 | 9603 | 8607 | 3 | Yes |
+--------------------+-----------------+-----------------+---------------+----------------------+----------------+-----------------+-----------------------------+----------+----------------------+----------------+------------+---------------------+
9 rows in set (0.00 sec)
その他コード
今回の解析、、というか見学？に使うのでパラメタ情報も確認しておきます。
mysql> SELECT * FROM epsg_coordoperationparam
-> WHERE parameter_name like '%translation%';
+----------------+--------------------------------------+-------------------------------------------------------------------------------------------------------+--------------------------------+-------------+---------------+-------------------+------------+
| parameter_code | parameter_name | description | information_source | data_source | revision_date | change_id | deprecated |
+----------------+--------------------------------------+-------------------------------------------------------------------------------------------------------+--------------------------------+-------------+---------------+-------------------+------------+
| 1040 | Rate of change of X-axis translation | Time first derivative of X-axis translation. | EPSG guidance note number 7-2. | EPSG | 2013-07-26 | 2013.021 2013.037 | 0 |
| 1041 | Rate of change of Y-axis translation | Time first derivative of Y-axis translation. | EPSG guidance note number 7-2. | EPSG | 2013-07-26 | 2013.021 2013.037 | 0 |
| 1042 | Rate of change of Z-axis translation | Time first derivative of Z-axis translation. | EPSG guidance note number 7-2. | EPSG | 2013-07-26 | 2013.021 2013.037 | 0 |
| 8605 | X-axis translation | The difference between the X values of a point in the target and source coordinate reference systems. | EPSG guidance note number 7-2. | EPSG | 2013-07-21 | 2013.021 | 0 |
| 8606 | Y-axis translation | The difference between the Y values of a point in the target and source coordinate reference systems. | EPSG guidance note number 7-2. | EPSG | 2013-07-21 | 2013.021 | 0 |
| 8607 | Z-axis translation | The difference between the Z values of a point in the target and source coordinate reference systems. | EPSG guidance note number 7-2. | EPSG | 2013-07-21 | 2013.021 | 0 |
| 8727 | Geocentric translation file | The name of the [path and] file containing a grid of geocentric translations.. | EPSG guidance note number 7. | EPSG | 2004-03-15 | | 0 |
+----------------+--------------------------------------+-------------------------------------------------------------------------------------------------------+--------------------------------+-------------+---------------+-------------------+------------+
7 rows in set (0.00 sec)
MySQLのST_SPATIAL_REFERENCE_SYSTEMSでの定義との照合
SRS_ID:6668 について、MYSQLのSRS定義の値がEPSGの定義のどこから来ているのかを確認してみる。
左側がMySQLの定義、右側がEPSGの定義から。
degreeの計算がやや定義として弱い（言葉で書いてある）けど、それ以外は元ネタを特定できました。
GEOGCS[
"JGD2011",
coord_ref_sys_name: JGD2011
DATUM[
"Japanese Geodetic Datum 2011",
datum_name: Japanese Geodetic Datum 2011
SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],
ellipsoid_name: GRS 1980
semi_major_axis: 6378137
inv_flattening: 298.257222101
ellipsoid_code: 7019
AUTHORITY["EPSG","1128"]
datum_code: 1128
],
PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],
prime_meridian_name: Greenwich
greenwich_longitude: 0
prime_meridian_code: 8901
UNIT["degree",0.017453292519943278,AUTHORITY["EPSG","9122"]],
unit_of_meas_name: degree (supplier to define representation)
unit_of_meas_type: angle
uom_code: 9122
factor_b: 3.14159265358979
factor_c: 180
remarks: = pi/180 radians. The degree representation (e.g. decimal, DMSH, etc.) must be clarified by suppliers of data associated with this code.
AXIS["Lat",NORTH],
coord_axis_order: 1
coord_axis_orientation: north
coord_axis_abbreviation: Lat
AXIS["Lon",EAST],
coord_axis_order: 2
coord_axis_orientation: east
coord_axis_abbreviation: Lon
AUTHORITY["EPSG","6668"]
coord_ref_sys_code: 6668
towgs84の根拠は
MySQLのJGD2024には towgs84の定義が含まれていません。これは古いEPSG定義には含まれていなかったものが、今になってもそのまま（最新化されずに）MySQL
で使われているせいだろうと推測しています。今回確認した EPSG v12.005では、towgs84の根拠となろう値はJGD2011にもきちんと設定されていました（ここでは値を紹介しませんが、ゼロでない数値が入っているtokyo測地系との比較をして確認しました）。
上で「その他パラメタ」として紹介したところから、6668->4326への変換定義と思われる部分だけを抜き出したものが以下のものです（カラムも減らしました）
+--------------------+-----------------+-----------------+----------------------+----------------+-----------------+------------+---------------------+ | coord_ref_sys_code | source_crs_code | target_crs_code | coord_op_method_code | parameter_code | parameter_value | sort_order | param_sign_reversal | +--------------------+-----------------+-----------------+----------------------+----------------+-----------------+------------+---------------------+ | 6668 | 6668 | 4326 | 9603 | 8605 | 0 | 1 | Yes | | 6668 | 6668 | 4326 | 9603 | 8606 | 0 | 2 | Yes | | 6668 | 6668 | 4326 | 9603 | 8607 | 0 | 3 | Yes | +--------------------+-----------------+-----------------+----------------------+----------------+-----------------+------------+---------------------+
この、parameter_codeが 8605, 8506, 8507のものが それぞれX,Y,Z方向への移動距離になります（ここでは省略しましたが、移動の単位が uom:9001、つまりメートルであることも定義されています）。以下が移動に関する定義です。
mysql> SELECT * FROM epsg_coordoperationparam
-> WHERE parameter_name like '%translation%';
+----------------+--------------------------------------+-------------------------------------------------------------------------------------------------------+--------------------------------+-------------+---------------+-------------------+------------+
| parameter_code | parameter_name | description | information_source | data_source | revision_date | change_id | deprecated |
+----------------+--------------------------------------+-------------------------------------------------------------------------------------------------------+--------------------------------+-------------+---------------+-------------------+------------+
| 1040 | Rate of change of X-axis translation | Time first derivative of X-axis translation. | EPSG guidance note number 7-2. | EPSG | 2013-07-26 | 2013.021 2013.037 | 0 |
| 1041 | Rate of change of Y-axis translation | Time first derivative of Y-axis translation. | EPSG guidance note number 7-2. | EPSG | 2013-07-26 | 2013.021 2013.037 | 0 |
| 1042 | Rate of change of Z-axis translation | Time first derivative of Z-axis translation. | EPSG guidance note number 7-2. | EPSG | 2013-07-26 | 2013.021 2013.037 | 0 |
| 8605 | X-axis translation | The difference between the X values of a point in the target and source coordinate reference systems. | EPSG guidance note number 7-2. | EPSG | 2013-07-21 | 2013.021 | 0 |
| 8606 | Y-axis translation | The difference between the Y values of a point in the target and source coordinate reference systems. | EPSG guidance note number 7-2. | EPSG | 2013-07-21 | 2013.021 | 0 |
| 8607 | Z-axis translation | The difference between the Z values of a point in the target and source coordinate reference systems. | EPSG guidance note number 7-2. | EPSG | 2013-07-21 | 2013.021 | 0 |
| 8727 | Geocentric translation file | The name of the [path and] file containing a grid of geocentric translations.. | EPSG guidance note number 7. | EPSG | 2004-03-15 | | 0 |
+----------------+--------------------------------------+-------------------------------------------------------------------------------------------------------+--------------------------------+-------------+---------------+-------------------+------------+
7 rows in set (0.00 sec)回転に関する定義値が6668に含まれていないのが気になりますが、これはtokyo測地系(4301)の場合でも同様だったので、回転については省略時はゼロという事に決まっているのかもしれません（根拠なし）。
まとめ
そんなわけで、測地系を語る上で一度は見ておきたかったEPSG定義を眺めてみました。 ちょっとクエリがまだイケてなくて、結合の過程で無駄に行が増えてしまったりして本当に見たい値をスムーズに見られるようになるところまでは到達できませんでしたが、なかなか面白い体験ではありました。
