1. Assesing climatological forcing information provided in NetCDF format in ArcGIS environment
CEE 6440 GIS in Water Resources
Fall 2004
Term Paper Presentation
ENRIQUE X ROSERO R

2. Motivation
Interest in crossing boundaries between GIS and Atmospheric Science communities.
First challenge in integrated analysis and display is data interoperability.
Objective
To present a general example of data set conversion.

3. Atmospheric data into GIS
Atmosphere has 3 spatial independent variables and changes in time
Scientific data include gridded output from numerical models, image data from satillites, point data from stations and trajectory from soundings
Layered data model conceptualization

4. Scientific Data Format: NetCDF
Machine-independent binary data format used for oceanographic and meteorological data exchange
Stores a multidimensional array of variables and attributes (data and metadata)
Interface through C, Fortran, C++, Java and Pearl libraries

5. Data interoperatibility
Scenarios to integrate and share information
Development of NetCDF converters for ingesting data into GIS
Series of TimeSeries Tables
API generates a snapshot in GeoTIFF format

6. Case: Rainfall events in Arkansas-Red Basin
Radar-derived precipitation stored in NetCDF

7. Use of available API for file conversion
ncBrowser allows no export
GDAL export GeoTIFF and ASCII grid but no geoinformation

8. Development of custom import tool
Fortran interface to retrieve data into array

9. Conversion Tools: ASCII to Raster
Straightforward
Precipitation grid projected onto a HUC

10. Precipitation event: 15 to 19 Nov 2004
Ready for raster calculation, zonal statistics, integration to modeling, etc.

11. Zonal statistics
Mean Median

12. Conclusions
Tons of information available in netCDF (e.g. OpenDAP, THREDDS)
There is no general nc2GIS conversion tool
Custom import has to be defined on a particular file structure basis
Seems unlikely that scientist replace particular tools (GrADS, Ferret, R, Matlab) with general purpose GIS tools
Have to wait years until a domain-specific data model is developed, files become standarized and conversion tools are provided

13. References Betancourt, T.(2003) Some concepts in Atmospheric data.
Yuan, M and Mcintosch, J. (2004). Data retrieval on spatiotemporal characteristics of weather events.
Nativi, S. et al. (2003) Differences among the data models used by the Geographical Information Systems and Atmospheric Science Communities.
Murray, D. et al. (2004) Integrating GIS data with Geosciences data in unidata’s IDV
Caron, J. and Nativi, S. (2004). NetCDF to GIS: the Good, the Bad and the Ugly.
Wilhelmi, O and Boehnert, J. (2004). Developing an Atmospheric Data Model for GIS.
Zeiler, M. (1999). Modeling our world.
Unidata (2002). NetCDF user’s guide for Fortran 90.
Unidata netCDF website:
NCAR GIS Initiative
ArcGIS Atmospheric Data Modeling of the Atmospheric Special Interest Group (SIG)
ESRI Atmospheric Data Model
NWS Arkansas Red Basin River Forecast Center.
USGS Hydrologic Unit Maps