Frequently Asked Questions
This list provides a source of answers to
commonly (and some uncommonly) asked questions regarding
the use of the UNILIB Library .
This list is roughly divided into
two categories: general questions and technical questions.
The latest version of this FAQ page can always be found at
If you have suggestions and comments please send an e-mail message
The information on this page and the subsequent ones is only related to versions of Unilib up to 2.09.
Please check www.mag-unilib.eu for more recent update.
G.01 What is the purpose of the library ?
G.02 Where to find the UNILIB library and documentation ?
G.03 Who is using the UNILIB library ?
G.04 How to install the IRI model ?
G.05 Which are the coordinates and units used ?
G.06 How to start using the UNILIB library ?
G.07 Does a similar software or library exist ?
G.08 How is defined a drift shell ?
G.09 How to quickly evaluate the capabilities of the UNILIB library ?
T.01 How to link the UNILIB library ?
T.02 Why is the object IRIS12 not resolved ?
T.03 How to customize the magnetic field model used by the library ?
T.04 Why are Roederer's L* and McIlwain's L parameters different ?
T.05 How to pass correctly the subroutine arguments in IDL ?
T.06 What is the precision of the field line tracing algorithm ?
T.07 Which subroutines are mandatory ?
T.08 How to link the library in IDL/PV-WAVE ?
T.09 What about a Linux version of the library ?
T.10 How to call the library from Win32 application ?
26-Aug-97, v1.05, R.01: Anomalous return of
subroutine UD310 with error code -41108
27-Aug-97, v1.05, UT985: Malfunction when field line extended to foot points
10-Sep-97, v1.06, R.02: Erroneous behaviour of most of the external magnetic field models
24-Oct-97, v1.07, UT550: Erroneous behaviour of the coordinate transformations relative to GSM and MAG coordinate systems
18-Dec-97, v1.11, R.03: Malfunction of subroutine UF426
14-Dec-98, v2.00, UL242: Lack of accuracy for low values of I
20-Jan-98, v2.00, UD315 and UD327: Error in the interpolation algorithm and inaccurate evaluation of the point with the lowest altitude