# Presentation: 767362

## Dapper and Argo

- Joe Sirott
- PMEL/NOAA

## What is Dapper?

- Web server that provides distributed access to in-situ data via OPeNDAP protocol
- Clients include GrADS, Matlab, NcBrowse, Java Ocean Atlas
- Available data:
- PMEL EPIC database
- ARGO profiles
- NODC World Ocean Database 2001
- All components are open-source

## What does Dapper do?

- Efficiently aggregates thousands of in-situ data files (>2000000 for WODB2001)
- Handles several in-situ data formats:
- Argo GDAC netCDF
- PMEL EPIC netCDF
- COARDS compliant netCDF
- Supports time series or profiles
- Supports space/time queries
- Based on HPCC funded Climate Data Portal (Soreide, Zhu, Denbo)

## What is OPeNDAP?

- OPeNDAP (Open source Project for a Network Data Access Protocol) is a protocol for remotely accessing scientific data
- Uses HTTP as transport

## Dapper OPeNDAP Example (space/time query)

- Client HTTP request:http://foo.org/.../dset.cdp.dods?lat,temp,pres&lat>0&lat<20
- Dapper HTTP response: Dataset {
-          Sequence {
-             Float32 lat;
-             Float64 _id;
-             Sequence {
-                Float32 pres,temp;
- 		} profile;
-          }
-       } location = { { -4.01,1, { {4.3,26.808}, {100,24.982}, ...},
-                    { -52, 2, {{8.3,3.77},{100,3.743},...}

## Dapper OPeNDAP Example (single profile)

- Client HTTP request:http://foo.org/.../dset.cdp.dods?lat,lon,time,profile&_id=20
- Dapper HTTP response: Dataset {
-          Sequence {
-             Float64 time;
-             Float32 lat,lon;
-             Sequence {
-                Float32 pres,temp;
- 		} profile;
-          }
-       } location = { {1034140577999,-52.9,310.144},                       {{8.3,3.77},{9.1,3.77},...}};

## Dapper architectural overview

- Uses relational database to store metadata and coordinate boundaries for each profile/time series file
- Data maintained in original format
- All data delivered as OPeNDAP sequences

## Dapper architecture

**CORBA (IIOP)**

** **

**Climate Data Portal **

** **

**MySQL**

** **

**Java netCDF**
**library**

**Dapper HTTP Server**

**OPeNDAP client****DChart**

**OPeNDAP Protocol**
**(HTTP)**

## DChart

- Browser based in-situ OPeNDAP client
- Based on FY2004 HPCC funded project for shipboard display of cruise data
- AJAX based user interface

## DChart Design Goals

- Highly responsive browser based user interface
- Low learning curve
- Rapid previewing and downloading of Dapper datasets
- Highly interactive map for region selection
- No Java applets or proprietary plug-ins

## Dapper architecture diagram

**CORBA (IIOP)**

** **

**Climate Data Portal **

** **

**MySQL**

** **

**Java netCDF**
**library**

**Dapper HTTP Server**

**OPeNDAP client****DChart**

**OPeNDAP Protocol**
**(HTTP)**

## DChart architecture

## DChart DemoNDBC videoArgo video

## CDFsync

- Rapid synchronization of netCDF in-situ files over a network
- Only compressed file differences transmitted across network
- Based on rsync, but optimized for netCDF and file lists consisting of thousands or millions of files
- Funded by HPCC 2004 (Charles Sun et al)
- Available at _[http://www.epic.noaa.gov/epic/software/cdfsync/](http://www.epic.noaa.gov/epic/software/cdfsync/)_

## Future plans

- Constraints (QC flags, attributes)
- Metadata display
- Trajectory and section plots
- Multiple plot windows
- Save/restore Web app state

## 

Questions?

- Questions?

## More info

- PMEL Dapper Server
- _[http://dapper.pmel.noaa.gov/dapper](http://dapper.pmel.noaa.gov/dapper)_
- PMEL Dapper UI
- _[http://dapper.pmel.noaa.gov/dchart](http://dapper.pmel.noaa.gov/dchart)_
- Downloads, propaganda
- _[http://](http://www.epic.noaa.gov/epic/software/dapper/)__[www.epic.noaa.gov/epic/software/dapper](http://www.epic.noaa.gov/epic/software/dapper/)__[/](http://www.epic.noaa.gov/epic/software/dapper/)_
- Joe.Sirott@noaa.gov

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