NGS recently announced their Alpha tools for the SPCS2022. I was pleased to be part of the stakeholder team that developed the new regional coordinate systems for the State of Texas.
alpha.ngs.noaa.gov
There will be many changes with the new TRF2022 datums and projections. The four TRF datums will be tied to ITRF2022 initially, but using the Euler pole transformation, position velocities will be minimized. Coordinate changes with NAD83 were maintained in such a way as to maintain coordinate value stability (as much as was possible). This contrasts with ITRF/IGS positions which change with the velocities relative to the Earth. For example, points in Texas move about 0.04' per year (1.3cm/yr). This means that an ITRF position in Texas will change by about 1 foot in 23 years, so the transformations used for TRF2022 will be important for making today's coordinates useful years from now.
The SPCS2022 will be limited to meters and international feet. Some States will only have a single projection (Tennessee, North Carolina and South Carolina come to mind). Some States will have a State-wide projection and will maintain the zone boundaries from SPCS83. Several States will include the State-wide projection, the NAD83 boundaries, and multiple smaller low-distortion projections. Texas has 50 such low-distortion zones. Those zones that have the same boundaries as the SPCS83 zones will not have the same parameters. The SPCS2022 is designed to minimize linear distortion and the Lambert systems are now single parallel. All parameters must meet certain numeric criteria, for example geographic coordinates of central meridian and latitude of origin must be in 6 minute intervals so that decimal degree values are not irrational. Because of this the mapping angle of any given points in SPCS83 will probably be slightly different from SPCS2022 in the same zone. The combined factor will definitely change, in almost all cases for the better.
We're still a couple of years from implementation, but it is good to see progress on this front. Software developers will do well to stay current on these releases.
Alpha Home | National Geodetic Survey
alpha.ngs.noaa.gov
There will be many changes with the new TRF2022 datums and projections. The four TRF datums will be tied to ITRF2022 initially, but using the Euler pole transformation, position velocities will be minimized. Coordinate changes with NAD83 were maintained in such a way as to maintain coordinate value stability (as much as was possible). This contrasts with ITRF/IGS positions which change with the velocities relative to the Earth. For example, points in Texas move about 0.04' per year (1.3cm/yr). This means that an ITRF position in Texas will change by about 1 foot in 23 years, so the transformations used for TRF2022 will be important for making today's coordinates useful years from now.
The SPCS2022 will be limited to meters and international feet. Some States will only have a single projection (Tennessee, North Carolina and South Carolina come to mind). Some States will have a State-wide projection and will maintain the zone boundaries from SPCS83. Several States will include the State-wide projection, the NAD83 boundaries, and multiple smaller low-distortion projections. Texas has 50 such low-distortion zones. Those zones that have the same boundaries as the SPCS83 zones will not have the same parameters. The SPCS2022 is designed to minimize linear distortion and the Lambert systems are now single parallel. All parameters must meet certain numeric criteria, for example geographic coordinates of central meridian and latitude of origin must be in 6 minute intervals so that decimal degree values are not irrational. Because of this the mapping angle of any given points in SPCS83 will probably be slightly different from SPCS2022 in the same zone. The combined factor will definitely change, in almost all cases for the better.
We're still a couple of years from implementation, but it is good to see progress on this front. Software developers will do well to stay current on these releases.
