LandscapeDNDC  1.36.0
Troubleshooting

Table of Contents

Simulation schedule

  • The time resolution of the simulation is independent of the time resolution of model inputs. E.g., climate data often is given with a daily resolution. For simulations with hourly time resolution, LandscapeDNDC automatically converts daily input to appropriate hourly input.
  • Events are only read within time schedule. E.g., if a forest is 'planted' at '2000-01-01' as defined in the event inputs and the simulation starts at '2001-01-01' then the forest will never be initialized since the time of the event is not within the simulation schedule.
  • Similarly, if a winter crop has been planted before winter, e.g., at '1999-10-01' and the simulation starts at '2000-01-01' then there will likely be a runtime error at harvest (e.g., at '2000-05-01') since the crop that is scheduled for harvest has never been planted.

Syntax

  • If a file cannot be read one likely error is a syntax error. Make sure that, e.g., the 'xml' syntax is correct. You can copy-paste the content of the respective file in an online-xml-validator. On Mac/Linux a command line xml validator named 'xmllint' can be used to validate xml syntax.
  • Pay attention of the correct delimiter in, e.g., climate or airchemistry inputs.

Others

  • The default value of missing or invalid inputs is '-99.99'. Make sure that the value is exact! A value of '-99.9' is technically a valid value for, e.g., temperature and will likely 'freeze' your simulation.
  • Check your file path length! For, e.g., MS Windows, the maximum length of a file path may be limited by 260 characters.

Errors

  • LandscapeDNDC distinguishes between setup/initialization errors and run-time errors. Setup/initialization errors occur during the setup and/or initialization of the modeling system. Usually the model is not in a state to log messages via its logging system and therefore the error messages are less detailed such as "can not read input source". This could mean that the file does not exist or that the file contains syntax errors (like XML inconsistencies) and therefore it can not be read in. First check the existing/naming of the project file. Be aware that Windows does not distinguish small and capital letters, while Apple Mac (may do) and Linux does. If the file exists, the cause of the error must be the syntax or the encoding (Encoding Errors see below). Run-time errors cause either a "segmentation fault" (which is a fatal error e.g. caused by a division by zero) and causes a termination without error handling, that means not explicit error/warning message). In case a systematic error occurs during run-time (e.g. tilling while there are living plants on the field, the model initiates a Fatal Error and an error message with 'EE' error code and error message will be written into the log system (–> see logging system).
  • Encoding Errors on Windows systems Windows users need to care about the encoding of text files. The LandscapeDNDC project file (ending with .ldndc) is a plain ascii text file. Typical encoding should be set to 'UTF-8', otherwise special characters such as double quotations '"', backslash '\' etc. may be interpreted inconsistent leading to uncontrolled behavior of the model.
  • LandscapeDNDC configuration file ldndc.conf LandscapeDNDC uses a configuration file for simulation runs. If the file is explicitly supplied in the model call via the '-c' option ldndc -c ldndc.conf arable/DE_gebesee/DE_gebesee.ldndc the local ldndc.conf file is used. If no configuration file is given, the default ldndc.conf file will be used. The default file is located in $HOME/.ldndc/ldndc.conf Typical errors occur because the ldndc.conf defines the global input_path. This input_path will be 'prepended' to the 'sourceprefix' of the project file.