Unfortunately, several elements of the CEOP-AEGIS Data Portal do cur- rently not work correctly with the employed Dapper / DChart distribution 2.2.0, released on October 3, 2009.
One of these problems concern the feature of DChart to center the interac- tive map at a specific location. This is realized by the GeoNames geographical database that is available as a web service for DChart. Due to a change of the URL of GeoNames, its database can no longer be accessed without an ad- ditional modification of the program code of DChart. To solve this problem, the entry ws5.geonames.org in the DChart file dchart/html/js/dchart.js must be changed to the value ws.geonames.org (J. Sirott, pers. comm., 22 March 2011).
Another problem concerns the download functionalities of DChart in case that gridded data is served by Dapper’s NetCDF service. The structure of downloaded NetCDF files as well as the values of the data variables remain correct, but the values of the coordinate variables become incorrect and cor- rupt the extent. Despite of correct data visualization in DChart and the fact that all data is conformal to the CF Climate and Forecast convention which is also supported by Dapper, this problem does occur for all kind of downloaded gridded data. According to J. Sirott (pers. comm., 4 February 2011), the released version of DChart that is employed as CEOP-AEGIS Data Portal (version 2.2.0) might have a bug that causes this problem. As Sirott informs, there does to be appear a difference in between the latest released version of Dapper / DChart and a newer version that is going to be published in the near future (J. Sirott, pers. comm., 4 February 2011). Following from this communication with the developer of Dapper and DChart, it is assumed that the download problems for gridded data served by Dappers NetCDF service will be solved as soon as the newer distribution of Dapper and DChart is published.
Several minor problems in matters of data type conversion have still to be solve within the data interface application. This concerns in particular some type conversions in between NetCDF and numpy. The external data types of NetCDF are independent from the internal data types of a particular programming language such as Python. Data within the CEOP-AEGIS Data Interface is translated in between internal and external data types for reading and writing processes from the intermediate data model to NetCDF and vice versa. Problems do in this regard occasionally occur in case that a data type of one representation does not clearly conform to the corresponding data type of another representation. Such problems exist within floating point data types of numpy that at some point need to be rounded in order to
obtain equally spaced values.
There is still a high potential in matters of expansion of the already avail- able functionalities of the CEOP-AEGIS Data Interface. Such an expansion would concern the capability to convert non-conformal NetCDF files to the intermediate data model. The current CEOP-AEGIS Data Interface allows to convert data in between the intermediate data model and the NetCDF file format, as long as conformance is given in respect to the determined CEOP- AEGIS data model. An additional functionality to convert non-conformal NetCDF files to the intermediate data model would be of a particular inter- est in regard of the provided input data obtained from CEOP-AEGIS project partners. Non-conformal NetCDF files could in such a case be easily made conformal by the use of the data interface application without of the need to first employ the translator libraries GDAL or GrADS. This might for ex- ample be desirable if NetCDF files store in-situ data and are already fully described in regard of their metadata content, but not structured conformal to the determined data model. Several approaches were already successfully employed to implement such a conversion tool within the CEOP-AEGIS Data Interface. Another interesting additional expansion would concern the print- ing functionalities of the data interface application. It is currently possible to print the complete NetCDF metadata as well as the complete content of the coordinate and data variables on the screen. In this regard it would be desirable if also specific content elements could be chosen for printing.
As soon as the successor of the actual compliance checker application for the newer CF Climate and Forecast convention version 1.5 will be released, it can be used to replace the current checker application that is implemented in the CEOP-AEGIS Data Interface. The employed version of this program can only check compliance against the older CF convention version 1.4. Due to the fact that no compliance checker application for the already released CF convention version 1.5 is available by now, the older version 1.4 of the CF convention was employed as part of the data model determination for CEOP-AEGIS.
To finally conclude, we believe that we can say that the current version of the newly developed CEOP-AEGIS Data Interface – which implements the determined CEOP-AEGIS data model for NetCDF – is a properly designed solution to achieve a maximum of compatibility within the CEOP-AEGIS Data Portal and subsequently interoperability within the interested scientific community. It is based on the open-source technologies NetCDF, OPeNDAP, Dapper and DChart that allow in their combination and by the use of the resulted work to fulfill the objectives of this thesis.
Appendix A
Appendix
Additional documentation as mentioned in the previous chapters can be found in this appendix.
A.1
CD-ROM of project data
A CD-ROM that is containing all relevant project data is attached to this thesis document. The content of this CD-ROM is organized by the use of the following folders:
Data
This folder contains the relevant project data that was produced as determined within this thesis. This is in particular:
• Program code of the CEOP-AEGIS upstream data interface to convert heterogeneous input data of project partners to standard- ized NetCDF output files, implemented in the Python program- ming language.
• Actual configuration files for the CEOP-AEGIS Data Portal, based on the Dapper / DChart technology.
• Cartographic products of CEOP-AEGIS project data in form of maps and video animations.
Thesis Document
This diploma thesis document with its associated files, as well as the bibliography database can be found in this folder.
Miscellaneous
Miscellaneous data is stored in this folder.