Cleaning out old emails found this pre-github enhancement request.
We recently needed to revisit a 2013 GNSS deformation survey of a network spanning approx. 20km.
Since then there have been a few upgrades to SNAP with a few revisions to the deformation model as well.
What we found is that when we ran the 2013 data with our currently installed version of SNAP 2.5.33, we were not able to replicate the results which we obtained in 2013 (which we had archived separately to the SNAP files which we re-ran).
Presumably this is just a function of a different version of the deformation model being utilised by the SNAP version we had installed in 2013 and the one we have installed today?
My assumption above may or not be correct, and really it doesn’t matter because we’ve just re-run 2013 & 2016 data sets without a deformation model in both, because in hindsight we’d prefer to know all changes between surveys in this case rather than having a regional deformation component of the changes removed.
But that has got us thinking about some useful enhancements for SNAP:
1) Could all historical deformation models be installed in SNAP’s library when installing the software, and could there be the ability to specify which deformation model (or none) is used via a drop-down menu with checkboxes (i.e. like is currently available for Geoid selection)?
2) We do small-scale deformation surveys at a few sites where we have inherited a local coordinate system which references NZGeoid2005. This and other of our clients have no interest in revising their vertical datum each time a new geoid model is published. Because of this we need to use historical geoid models in order to replicate network adjustment of repeat surveys by a consistent methodology in order to derive changes between surveys. Would it be possible for SNAP to include all of LINZ’s historical Geoid models? i.e. NZGeoid2005, NZGeoid2009 & NZGeoid2016 all installed in SNAP library upon installation of SNAP and accessible via the SNAP geoid drop-down menu?
3) Reducing and adjusting our deformation surveys is often an iterative process, and it would be really useful to be able to quickly turn a geoid off via the menu option rather than via text edits of the CRD file. Any chance of a “no geoid” switch on the SNAP geoid drop-down menu?
Cleaning out old emails found this pre-github enhancement request.
We recently needed to revisit a 2013 GNSS deformation survey of a network spanning approx. 20km.
Since then there have been a few upgrades to SNAP with a few revisions to the deformation model as well.
What we found is that when we ran the 2013 data with our currently installed version of SNAP 2.5.33, we were not able to replicate the results which we obtained in 2013 (which we had archived separately to the SNAP files which we re-ran).
Presumably this is just a function of a different version of the deformation model being utilised by the SNAP version we had installed in 2013 and the one we have installed today?
My assumption above may or not be correct, and really it doesn’t matter because we’ve just re-run 2013 & 2016 data sets without a deformation model in both, because in hindsight we’d prefer to know all changes between surveys in this case rather than having a regional deformation component of the changes removed.
But that has got us thinking about some useful enhancements for SNAP:
1) Could all historical deformation models be installed in SNAP’s library when installing the software, and could there be the ability to specify which deformation model (or none) is used via a drop-down menu with checkboxes (i.e. like is currently available for Geoid selection)?
2) We do small-scale deformation surveys at a few sites where we have inherited a local coordinate system which references NZGeoid2005. This and other of our clients have no interest in revising their vertical datum each time a new geoid model is published. Because of this we need to use historical geoid models in order to replicate network adjustment of repeat surveys by a consistent methodology in order to derive changes between surveys. Would it be possible for SNAP to include all of LINZ’s historical Geoid models? i.e. NZGeoid2005, NZGeoid2009 & NZGeoid2016 all installed in SNAP library upon installation of SNAP and accessible via the SNAP geoid drop-down menu?
3) Reducing and adjusting our deformation surveys is often an iterative process, and it would be really useful to be able to quickly turn a geoid off via the menu option rather than via text edits of the CRD file. Any chance of a “no geoid” switch on the SNAP geoid drop-down menu?