David R. Maidment Unidata Program Center, Boulder CO 6 Feb 2004 From netCDF to GIS David R. Maidment Unidata Program Center, Boulder CO 6 Feb 2004

NetCDF and GIS NetCDF describes atmospheric and water properties varying continuously in (x,y,z,t) GIS describes the physical landscape, Vector GIS has spatially discrete features (point, line area) Raster GIS is spatially continuous (in 2D) How do we connect the “water” with the “water environment”

NetCDF File for Model Output dimensions: lat = 5, lon = 10, level = 4, time = unlimited; variables: float rh (time, lat, lon); int lat(lat), lon(lon); lat:units = “degrees_north”; long:units = “degrees_east”; short time(time); time:units = “hours since 1996-1-1”; data: lat = 20, 30, 40, 50, 60; long = -160, -140, -118, -96, -84, -52, -45, -35, -25, -15; time = 12; rh = .5,.2,.4,.2,.3,.2,.4,.5,.6,.7, .1,.3,.1,.1,.1.,.1,.5,.7,.8,.8, .1,.2,.2,.2,.2,.5,.7,.8,.9,.9, .1,.2,.3,.3,.3,.3,.7,.8,.9,.9 .0,.1,.2,.4,.4,.4,.4,.7,.8,.9;

Relative Humidity Points

Interpolate to Raster GeoTiff format, cell size = 0.5º

Zoom in to the United States

Average Rh in each State Determined using Spatial Analyst function Zonal Statistics with Rh as underlying raster and States as zones

Unidata Toolbox Relative Humidity Analysis Model Created in Arc 9 Model Builder

Model Output Geodatabase (Grids) Geodatabase Feature Dataset Feature class Feature class Raster Catalog Relationship Raster Table Table

Raster Catalog has Types of Data

Scenarios for Data Dissemination ArcSDE and ArcIMS Leveraging the Unidata Local Data Manager (LDM) Access through Unidata Internet Data Viewer (IDV) Direct downloads from ArcGIS

Scenario 1: ArcIMS & ArcSDE Underlying data are stored in a relational database (e.g. Oracle) Accessed through Arc Spatial Data Engine (ArcSDE) Web access through Arc Internet Map Server (ArcIMS) Used for National Elevation Dataset, National Land Cover Dataset, National Hydrography Dataset Suitable for large static databases Possibly a good approach for historical climate datasets, e.g. VEMAP (NCAR: Nan Rosenbloom, Dave Schimel, Tim Kittel) National Elevation Dataset

Scenario 1: ArcIMS & ArcSDE User Experience Go to a web site, browse available data and select a geographic region and desired data themes “Download” means that a data product is created off-line and user is notified by email when it is ready If < 100MB download via ftp for free If > 100MB write to CD-ROM and mail ($$) Contacts: Paul Wiese, USGS, Denver (NHD); Sue Greenlee, USGS, EROS Data Center (NED, NLCD) National Elevation Dataset

Scenario 2: Leverage the LDM File is disseminated through LDM network e.g. netCDF format Unidata publishes an Arc Toolbox for converting file (or adds a decoder to LDM to convert to Grid) Good for GIS analysis of existing real time data stream

Scenario 3: Access through IDV IDV is used to browse remote datasets Protocol to access Geography Network is added to IDV Geographic data added to IDV displays Atmospheric data converted to GeoTIFF for GIS analysis Build Raster Catalog of atmospheric datasets Data Publisher 1 Data Publisher 4 Data Publisher 2 Data Publisher 3 Meteorologix publishes atmospheric data on the Geography Network

Scenario 4: Direct Downloads from ArcGIS Select region and time period Launch query to http:// access Download data Import to geodatabase Run models Nexrad data for July 30, 2001, Rosillo Creek

Nexrad for Rosillo Creek

GIS in Water Resources Consortium CRWR GIS Water Resources Bringing together these two communities by using a common geospatial data model

Arc Hydro — Hydrography

Arc Hydro — Hydrology

Arc Hydro Framework Data Model The Arc Hydro framework is built on a Hydro Network made up of HydroEdges (stream lines) and HydroJunctions (points of interest on the lines). The watersheds, waterbodies and hydropoints are connected to the hydronetwork using relationships with the hydro junctions (blue lines in the diagram).

Arc Hydro Framework For South Florida Basins Waterbody (NHD) The Arc Hydro Framework is a simplified version of the full Arc Hydro data model designed for an entry level user who just wants to put together a basic data set for streams, watersheds, waterbodies and hydro points like stream gages and water quality monitoring points Hydro Points National Hydrography Dataset, NHD

Arc Hydro Components Drainage System Hydro Network Time Series Flow Time Time Series Channel System Hydrography

Connecting Arc Hydro and Hydrologic Models GIS Interface data models HMS Geo Database Arc Hydro data model RAS WRAP

Nexrad Map to Flood Map in Arc 9 Model Builder FLOODPLAIN MAP Flood map as output Model for flood flow HMS Model for flood depth Nexrad rainfall map as input

Time and Space in GIS Time Series Feature Series Attribute Series Variable t3 Value t2 t1 Time Attribute Series Raster Series Value t3 t1 t2 t2 t1 t3 y x

Time Series and Temporal Geoprocessing DHI Time Series Manager Time Series Feature Series Time Variable t3 Value t2 t1 Time Attribute Series Raster Series Value t3 t3 t2 t1 t2 t1 y x ArcGIS Temporal Geoprocessing

Time series from gages in Kissimmee Flood Plain 21 gages measuring water surface elevation Data telemetered to central site using SCADA system Edited and compiled daily stage data stored in corporate time series database called dbHydro Time series downloaded from dbHydro and stored for all gages as Arc Hydro Attribute Series

Arc Hydro Attribute Series Map features have a time varying attribute HydroID 2906 Feature Class (HydroID) Attribute Series Table (FeatureID)

Raster Series Ponded Water Depth Kissimmee River June 1, 2003

Arc Hydro Attribute Series Object TSDateTime Feature Class (point, line, area) TSValue FeatureID TSType TSType Table

NetCDF Data Model Time Dimensions and Coordinates Value Space (x,y,z) Variable Attributes

Conclusions Good time to make progress Unidata THREDDS research done at Unidata and some experience accumulated Arc 9.0 is about to be released with Model Builder; planning for Arc 9.1 about to begin Fairly sound understanding of how to develop time series in ArcGIS Lots of cool weather and climate data that we really, really would like to use more!!