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

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.

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

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

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

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

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

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

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

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

Zonal statistics Mean Median

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

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: http://my.unidata.ucar.edu/content/software/netcdf/index.html NCAR GIS Initiative ArcGIS Atmospheric Data Modeling of the Atmospheric Special Interest Group (SIG) http://www.gis.ucar.edu/sig/data_model/data_model.html ESRI Atmospheric Data Model http://support.esri.com/index.cfm?fa=downloads.dataModels.filteredGateway&dmid=36 NWS Arkansas Red Basin River Forecast Center. http://www.srh.noaa.gov/abrfc/precip/index.shtml USGS Hydrologic Unit Maps http://water.usgs.gov/GIS/huc.html