# Presentation: 548095

## 

National Virtual Pointer System (NVPS)

Global Justice XML Data Model Users Conference
June 9, 2005
Atlanta, GA

**National Virtual Pointer System (NVPS)**
**Global Justice XML Data Model Users Conference**
**June 9, 2005**
**Atlanta, GA**

## Presenters

- Brian Dawson
*Systems Manager, Midwest HIDTA*
- Bill Edgin
*Senior Principal Consultant, Drug Enforcement Administration*
- Carl Nelson
*Lead Developer, RISS Applications Development Group*
- Kate Silhol
*Senior Software Engineer, NLETS*

## What Is the National Virtual Pointer System?

**XML and Web Service based system connecting Federal, State, and Local, & Tribal agency target deconfliction systems**
**Built on GJXDM 3.0 prerelease, to be updated to 3.0.3 during Fiscal Year 2005**
**Matches return officer contact information**
**Goal of the system: Put officers in contact with each other**

## Current Participants

- DEA (NDPIX)
- HIDTA program (Appalachia, Chicago, Gulf Coast, Midwest, New England, South Florida, South Texas)
- Missouri State Highway Patrol (MoSPIN)
- NLETS
- RISS (RISSNET)

## System Architecture

- No direct communication between systems
- Systems connect only to NVPS Message Hub
- Hub validates and routes data
- Networks involved:
- RISSNET: Provider to HIDTAs and MoSPIN, host of NVPS Message Hub
- NLETS: Provider to NDPIX and able to provide for other NLETS users
- USDOJ: Provider to NDPIX

## Message Formats & GJXDM Usage

- NVPS Message Format: Built to GJXDM 3.0 Prerelease, to be updated to 3.0.3
- NLETS Message Format: Currently uses NLETS’ pre-GJXDM format, to be updated to NLETS’ GJXDM-compliant format
- NDPIX Message Format: Text-based parsed format

## XML Format Development

- Identification of Data Elements
- Policy & Legal Requirements
- System commonality
- Identification of most valuable data elements to an end user
- System Requirements & Header Information
- Routing
- Tracking
- Identification

## XML Format Development

- Tools Used:
- GJXDM Wayfarer
- XML Spy
- Microsoft Visual Studio

## Problems Encountered During XML Format Development

- “Moving Target”: GJXDM 3.0 prerelease
- Lack of commonality of code values between systems caused some required elements to become optional!
- No Subschema Generation Tool—manual process introduces possibility of errors
- Few guidelines or best practices for GJXDM at development time
- Use of namespaces needs to be updated with current best practices
- Format needs to be updated using SSGT & GJXDM model of subset schema & proxies, constraint/extension schema, and implementation—Can this be done with no impact?

## Technical Challenges

- Class generation: used tools such as Microsoft’s xsd.exe to generate classes from schemas
- GJXDM elements contain far more properties than were needed in the system: Constraint schema
- GJXDM elements by default create 0-to-many instances: Constraint schema
- Extension moves GJXDM element into local namespace!

## Translation

- NVPS format must be translatable to and from NLETS format
- NLETS format must be translatable to and from NDPIX format
- XSLT: too slow for production use
- Solution: convert XML formats to and from base classes

## “Clearinghouse-to-Clearinghouse” Methodology

- NVPS may reach a very broad audience of users of NLETS’ format
- More moving pieces = More things that can go wrong!
- NLETS use of GJXDM
- Only header information and wrappers need to be translated
- Greatest benefit of GJXDM usage: clearinghouse specifications may be easily mapped to each other with common elements!

## Lessons Learned

- Define data model as early as possible
- Use SSGT after data modeling is complete elements are identified: it’s hard to go back after changing constraints and minOccurs/maxOccurs
- Provide regular communication between participants
- Identify networks, vendors, formats, personnel, tools, and commercial products used
- Network issues are showstoppers until resolved: identify early!