Mapping with GPS /integrating location based information with GIS databases

Agenda  GPS Data Collection  Census Mapping with Trimble  GPS Data Maintenance  Summary

GPS Segments Control Segment Monitor Stations User Segment Space Segment Control Segment

<20 m Standard Positioning Service - Autonomous GPS

<12 m Precise Positioning Service- PPS P(Y) Code GPS

<2m Base Station Mapping Grade Receiver-DGPS

<1m Base Station High Quality Mapping Receiver SPS-DGPS

<1cm RTK Base Station Real-Time Kinematic Surveying

<1/2 cm Base Station Survey Grade GPS

20 m 2m 1m 12m 1/2cm 1cm Where Do You Need to Be?

50 m 2m 1m 12m 1/2cm 1cm Real-Time or Postprocessed?

Examples of Different Accuracy Requirements  Code Phase GPS  40 m- Navigation at sea  10 m- Navigation to section corners  2 m- Rural GIS data capture  1 m- GIS data collection in urban area  Carrier Phase GPS  1 cm- Stake out  ½ cm - Control Surveys

Differential Correction  Base Station generates corrections for all satellites in view  Roving GPS receiver uses corrections to reduce errors  Differential correction can be performed in either real-time or postprocessed mode

BASE Time, t t + 1 GPS Positions Absolute Reference Position Differential Correction (Simplified)  If you collect data at one location, there will be errors  Each of these errors are tagged with GPS time

ROVER Time, t t + 1 ? Differential Correction (Cont.)  At the same time, the errors occurring at one location are occurring everywhere within the same vicinity

Satellites Seen Satellites Used Any Combination of Base satellites ROVER Time, t t + 1 ? BASE Time, t t + 1 Differential Correction (Cont.)

Example of Uncorrected File

Example of Corrected File

Base Station: 15°Rover: 15° Poor Situation – Satellite visible to Rover only. Base Station is not tracking it. Possible Problem...  setting the elevation masks

1° per 100 km distance between base and rover Base Station: 10°Rover: 15° Ideal Situation – Satellite is being tracked by both Rover and Base Station. Solution...  Set base elevation mask less than rover

Why GPS ?  Satellite-based.  Digital Coordinates  Fast & Acceptable Accuracy  Easy integration with Most GIS Software  More suitable for extended application of GIS e.g.  Census Data Analysis  Emergency Services  Location Based Services  Disaster Management  Asset Management

GPS Data Collection  Collection of Geographic Data (GI)  Points, Lines, Areas  Offset locations  1 to 5 meter precision  Customized attribute information  Menu lists, Text, Numeric, Dates and times  Multiple data dictionary support  Infield data dictionary creation

2. Census Mapping with Trimble  Trimble Mapping is High-end Mapping Grade Receiver to be used for  Recording something, somewhere (What do I have?)  Navigation  Finding something, somewhere (Where is it?)  Updating  Verifying something, somewhere. (Is the information I have correct?)

Juno ST GPS Handheld Stylus holder Headset connector Reset button GPS antenna connector Power button Lock switch Power/USB socket SD card slot Directional button Contacts Messaging Today screen Calendar

Performance Postprocessing  Improve the overall quality and consistency of your data by postprocessing … Juno ST Autonomous HRMS 2.11m Bias 0.63m Worst 5.6m Juno ST Postprocessed HRMS 1.12m Bias 0.55m Worst 4.6m

Recon XC GPS Receiver  The GPS Pathfinder ® XC receiver is totally enclosed beneath the extended CF-Cap™  No receiver or antenna cables to snag or break  Plug and play with CompactFlash  Achieve 2 to 5 meter postprocessed accuracy  Requires field software capable of logging data for postprocessing  TerraSync™ software  ArcPad with the Trimble GPScorrect ™ extension  Applications created with the GPS Pathfinder Tools Software Development Kit SDK  Also requires office processing software  GPS Pathfinder Office software  Trimble GPS Analyst ™ extension for ESRI ArcGIS software

Rugged and weatherproof  IP 67  Sand and dust: MIL-STD-810F, Method 510.4, Procedures I and II  Water: MIL-STD-810F, Method 512.4, Procedure I (submersion in 1 meter of water for 30 minutes)  Wide operating temperature range  –10 °C to 50 °C (14 °F to 122 °F)  Drop specification  4 ft (1.22 m)  MIL-STD-810F, Method 516.5, Procedure IV  Vibration resistant  MIL-STD-810F, Method 514.5

Trimble Recon GPS XB edition  Affordable  Equip your entire mobile workforce  Reliable 2 to 5 meter accuracy  Using SBAS or postprocessing  Rugged field computer  Cable-free  Bluetooth ® wireless technology connection to GPS Pathfinder ® XB receiver  Choice of field software

Compared with Trimble Recon GPS XC edition Trimble Recon GPS XB edition Trimble Recon GPS XC edition Built-in Bluetooth wireless technology No built-in wireless External GPS receiverInternal GPS receiver SBAS for real-time 2 to 5 meter DGPS accuracy Can also post-process No SBAS Use post-processing to achieve 2 to 5 meter accuracy

Trimble Recon handheld  Key Features  Ultra-rugged and lightweight  IP 67  Integrated wireless options  Optional built-in Bluetooth ® wireless technology and wireless LAN  Range of systems to best meet your needs  Select from 3 different Trimble Recon handheld systems  GPS functionality easily added  TrimPix™ technology wireless camera support

GeoExplorer 2005 series  Three models: three levels of accuracy  GeoXH™ handheld—Subfoot (with H-Star™ technology)  GeoXT™ handheld—Submeter  GeoXM™ handheld—1–3 m  Microsoft ® Windows Mobile ® version 5.0 software  Maximum flexibility in software choice  512 MB onboard storage plus removable SD card storage  Bluetooth ® and b Wireless LAN connectivity options  Rugged handheld with all day battery  TrimPix™ technology for wireless camera support

Voice Message  Pocket PC Voice Recording System  Ideal for Diverse Data Collection with various groups of people using the unit  Save time  Accurate and Detailed Database

TrimPix technology support  Support for digital image transfer using wireless LAN  Using built-in wireless LAN or wireless LAN CF card  Receive high resolution digital images from selected Nikon digital cameras  The easy way to integrate digital images into your GIS

 Photographs are rich in detail  Photographs can be used as evidence Hence :  No cost in describing the site  Add minimal extra cost but add more details to GIS data u Free to download from Adding Photo to your GIS data

Need to know...  How many people...  Where they are …  What are the people nationality in the area...  What condition they are…  Who are they ?  Why?  Answers  Tools for better Decision Making

3. GPS Data Maintenance  Building a GIS database is a bit like building a bridge...  It has a design and construction stage…

Data Maintenance  But if its not maintained, it becomes useless and can create problems.

Data Maintenance  Maintenance for a GIS means keeping its data up-to-date, accurate, and reliable.  Features may need to be:  added  modified  deleted  restructured

Data Maintenance  Data becomes out-of-date for many reasons, such as:  new infrastructure  storm damage  changing user requirements  New analysis criteria

Data Maintenance  The Data Collection/Maintenance Cycle 1. GIS to Field 2. Field Update 3. Field to GIS

The way we are heading… Data UseData Maintenance Where we have been Where we are headed Data Collection

The Future  Further Improvements on GPS  Cheaper price with more capabilities  More accessible to all users  More Flexible application  More Accurate Coordinates  Better Data Communication  Better GIS data

Summary  GPS is a reliable source of GIS data  Trimble continues to provide the most reliable GPS Receivers  More functionalities are added into GPS Receivers  When the Data Collection is done, Data Maintenance must already been planed and committed   Better Decision Making & Analysis

Thank You.