Sorry I didnt intend to send this to the whole list. My bad. I also attached the wrong dataset ;( I apologise.
Em sáb., 16 de dez. de 2023 às 17:43, Meridiana GeoTopo < meridianageot...@gmail.com> escreveu: > Riccardo, thanks for replying. > Let me provide more information , as I reckon I did a bad job the first > time ;) > > Thanks for the welcoming! > The tricky bit of analysis will handle angles, distances and deltas of > those variables, since everything needs to be georeferenced, every > observation takes a coordinate pair (X,Y or N,E) but also Z (X,Y,Z). > The data will take the form of a panel model, with a benchmark value for > the base variables (the average of a few dozen observations ) and the > recurring measurements shall be compared against the benchmark, and once > enough data is collected, we'll try to understand various relationships > amongst variables and their observed values. > My emphasis on the (XYZ) is that though rain, temp, exogenous impacts, etc > play a role in the *seasonal* observations therefore recurring, the > coordinates are observed down to a high precision (mm) and changes in them > may flag changes in the observed values which are not related to any > recurring cycle but a deterioration in the condition of a specific > location, and many tests and hypothesis will be checked for > each observation. There geo variable should be so interrelated that I > expected > > y= a + b*sin(x) is a generalization for an accumulation of a geographical > position, such as Y = Yi + d*sine(alpha) for example. When I run an OLS the > results seem to explain very little of what I expected to be a > straightforward and linear expression, specially because it's a panel and I > am comparing the same data which is expected to change very little between > observations/measurements. > So first of all I need to script for checking 1mm change in coordinates > (above or below each variable X, Y, Z) then check for season impacts etc. > I am attaching an example file with test measurements. Important detail > (in order to make sense of data) is that I am creating a BENCHMARK value > for XYZ (average value) and creating variables DeltaX/Y/Z which are the > ones I will compare against 0.001m (1mm) change by doing ex. Delta_X(i) = > X(i) - mean(X) etc. I also should say that the dataset used a less precsa > equipment so it is very hard to check for 1mm changes, as per OLS , the > results will tell. > My idea is to use tests to check if the changes breach a critical value > and if they relate to seasonal factors (no big deal) or they are indeed red > flags. > Any ideas how you'd run this? > > Cheers from Brazil! > > Em sex., 8 de dez. de 2023 às 11:51, Riccardo (Jack) Lucchetti < > p002...@staff.univpm.it> escreveu: > >> On 08/12/2023 14:52, Meridiana GeoTopo wrote: >> > Hello Gretl Enthusiasts! >> > >> > I hope this message finds you well. I am reaching out to this >> > knowledgeable community as I embark on a unique project that involves >> > utilizing Gretl for the estimation of environmental and engineering >> > parameters. While I've already dived into Gretl for this purpose, the >> > project's diversity from traditional econometrics poses a few >> challenges. >> >> Welcome to the community! >> >> > Specifically, I am looking to run regression models where I can create >> > custom formulas and expressions. To give you a glimpse, my requirements >> > involve working with a Cartesian coordinate system, something like y = >> a >> > + d(sine(b)), as I heavily rely on spatial data in my study and also >> > structural health. >> >> Some clarification is needed here. If (as I believe form the context) a >> and b are parameters and d is an observable series, then all you need is >> OLS plus the application of the delta method in order to recover the >> estimate of b and its standard error. Otherwise, if b is an observable >> series, then sin(b) is an observable series too, and a distinction must >> be made according to what the "d()" expression means. If it means "a >> parameter called d multiplied by something", then OLS suffices, again. >> Otherwise, if it means "the function d() applied to something", where >> this function continuous and differentiable, then what you need is NLS. >> >> All these methods are provided by gretl, so feel free to ask for guidance. >> >> > I could also use TLS and GLS models - can I run them in gretl and if so >> > where can I find examples of implementations? >> >> The TLS model as such is not implemented in gretl natively, since it's >> very seldom used (if ever) in econometrics. However, we do have a >> function for performing the SVD and it shouldn't be difficult to write a >> script to perfom TLS estimation. As for GLS, it really depends on what >> you need (GLS is a very generic term that could be applied to many >> different things). If what you need is the special case known in >> econometrics as "weighted least squares", then yes, we do have a "wls" >> command. >> >> > Later we will attach soil, air, temperature, rain etc to the model but >> > these will follow a linear model approach easily. >> > >> > As a newcomer to Gretl, I am seeking honest assistance, guidance, and >> > insights from the experienced members of this group. If anyone could >> > spare a moment to share your expertise, provide script help, or guide >> me >> > on using the GUI to achieve these objectives, I would greatly >> appreciate it. >> > >> > Your support will not only contribute significantly to the success of >> my >> > project but will also help me enhance my understanding of Gretl in a >> > practical context. I am eager to learn and absorb insights from the >> > Gretl community. >> > >> > Thank you in advance for your time and assistance. I look forward to >> the >> > valuable input from this esteemed group. >> >> Feel free to ask! >> >> ------------------------------------------------------- >> Riccardo (Jack) Lucchetti >> Dipartimento di Scienze Economiche e Sociali (DiSES) >> >> Università Politecnica delle Marche >> (formerly known as Università di Ancona) >> >> r.lucche...@univpm.it >> http://www2.econ.univpm.it/servizi/hpp/lucchetti >> ------------------------------------------------------- >> _______________________________________________ >> Gretl-users mailing list -- gretl-users@gretlml.univpm.it >> To unsubscribe send an email to gretl-users-le...@gretlml.univpm.it >> Website: >> https://gretlml.univpm.it/postorius/lists/gretl-users.gretlml.univpm.it/ >> >
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