Mobile GIS UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Slide 1 UNSD Workshop Pieter van Jaarsveld An Overview to a professional.

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 1

Mobile GISUNSD Workshop

Pieter van Jaarsveld

An Overview to a professional GPS/Mapping collection solution

Mobile GIS Specialist

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 2

Survey

Recreational GPS users?In-car navigation users?Capturing GPS data in the field for GIS use?Plan to in the next year?

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 3

Global Positioning System

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 4

Global Positioning System

• Where on earth am I ?

Constellation of satellites

Handheld devicesVarious ApplicationsAccuracy

What is GPS?

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 5

1

Correct for Atmosphere & Ionosphere

Differential Corrections

43

Trilateration using speed of light

Accurate clocks are required2

Use ephemeris for satellites’ location

5

GPS in 5 Basic Steps

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 6

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 7

Control SegmentProvides worldwide coverage and control

• 365/24/7

Master Control station• Colorado

Four support stations• Hawaii• Kwajalein• Diego Garcia• Ascension Island

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 8

Space SegmentGPS satellite constellation

• 24 satellites• Replenishment occurring

Satellite design • Lifetime 7.3 years• 16 satellites over 9 years old

28 Satellites in GPS Constellation

0

2

4

6

8

10

12

Under 3 3-4 5-6 7-8 9-10 11-12 13+

Age (Years)

Nu

mb

er

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 9

User SegmentEquipment produced by Military and Private

companies

Receives signal and computes• Position• Time• Velocity

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 10

How do we position ourselves?

Simple Geometry• Velocity times vs travel time

Determine Radio Wave Time Travel • Accurate timing

Measure Distances• Known orbit locations

Trilateration• Distances not angles

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 11

Sources of Positioning ErrorIonosphere and Atmospheric delays

Satelite and receiver Clock Error

Multipathing

Dilution of Precision

Receiver Issues

Selective Availability

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 12

• Two receivers track the SAME signals and errors at the SAME time

• Derived corrections are then applied to the data during postprocessing

– GPS Analyst contains tools for DC• Does not correct multipath

Base

Data Collector

Differential GPS

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 13

Red = Uncorrected GPS

Green = GPS after differential correction

Differential Correction

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 14

Selecting a GPS

Recreational versus Professional GPSAccuracy

• Tens of meters versus sub meter

GIS data integration• Format conversion

Attribute collection• Customised forms, business rules

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 15

Data Collection Software

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 16

Data Collection Workflow (server to server)

ServerServer DesktopDesktop MobileMobile DesktopDesktop ServerServer

Enterprise Geodatabase

Export to PGDB

Check out

Copy to device

ArcPad

Copy to Desktop

Check In

Post process

Import to Enterprise

Data validation

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 17

Check out and post processing is performed on a personal geodatabase NOT directly from enterprise. WHY?•GPS detail not required in enterprise•Topology not supported in GPS Analyst

Carefully choose extents. WHY?•Large extent limits the amount of data capture

Current only personal geodatabase support, efforts to supporting file geodatabase underway.

UC 2007 Tech SessionsUC 2007 Tech Sessions 1717

Data - things to remember

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 18

What is ArcPad?•Part of ESRI overall mobile strategy•A mobile GIS application for field mapping applications

•Designed for broad range of mobile systems•Allows input from GPS receivers, rangefinders, digital cameras and other devices

•Provides a generic set of mobile GIS functionality •Extensive customization capabilities•Extends Geodatabase to the field through disconnected editing

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 19

What can you do with ArcPad? • Use your existing data • Add data from the Internet• Move around your map• Query your data• Edit your data• Measure distance, area, and bearings on your map• Navigate with your GPS• Customize ArcPad to streamline your workflow

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 20

ArcPad BenefitsStreamlines the workflow

• Smart, task oriented solutions

Increases productivity• Reduces office work and data entry time • Improves the accuracy of data• Resulting in more accurate and current data for

analysis and decision making

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 21

ArcPad FunctionalitiesImproved performanceEnhanced editing tools

• Snapping• Undo• offsets for points, lines, polygons• repeated features• segmented line features

Camera and rangefinder supportImproved symbology and labelingSupport for Graphics layer

• for redlining or mark-upImport/export tools for ArcGISCustomization

• wizard for creating custom forms

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 22

ArcPad FunctionalitiesSignificant performance gains on startup time

• Pre-buffering input• Affects Applets, Layers, Scripts etc. (i.e ALL XML and

Scripts)• Delayed loading of projection data

Usability enhancement• Datum conversion wizard• Picture browsing capabilities on Windows Mobile 5 devices• Additional language packs available

Quality improvements• About 80 bugs have been identified and fixed!

Minor feature improvements• Object model improvements (Picture chooser, File object ,

Inter-process methods)

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 23

Configuring the GPS

Protocol = “Trimble GPSCorrect” or “NMEA0183”Port = “COM3: TSIP Serial Port (GeoExplorer)Port = “COM7: TSIP Serial Port (JunoST)Port = “COM2: TSIP Serial Port (Recon XC)

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 24

Streaming and AveragingAveragingnumber of incoming GPS position

coordinates that ArcPad uses for calculating an average coordinate

StreamingPosition Interval = How frequently

ArcPad uses incoming GPS coordinates

Distance Interval = ArcPad uses incoming GPS coordinates only when greater than this distance from LAST coordinate used

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 25

GPS PreferencesQualityMinimum and maximum values can be

predefinedCan be made compulsory to ensure

data integrity

Warning and AlertsVisual and Audio alertsConstantly warns the user if not

complying to presetsWill inform the user of GPS statusCan be annoyingCan be switched off

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 26

Editing using the GPSFirstly, make layer

editable (one point, line, polygon, at a time)

Then select feature type

Then select GPS capture tool

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 27

UC 2007 Tech SessionsUC 2007 Tech Sessions 2727

DOPDOPSV GeometrySV GeometryHigh = BADHigh = BAD

Low = GOODLow = GOOD

SNRSignal to

Noise Ratio

High = AccurateLow = Productive

Elevation MaskElevation MaskDefault 15Default 15

No. of SatellitesMin of 4 SV’s

Ensuring data quality

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 28

ArcPad with other devicesArcPad can be used with:

• Digital Cameras• WiFi enabled cameras• BT enabled camerasUse “Camera” tool• Photo Layer• Custom Form

• Laser Rangefinders• What is your accuracy needs?

• External GPS

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 29

Where are the Satellites? • Your Body is an obstruction!

Point Data Collection • Position First and Attributes Second

Polyline & Polygon Collection • Streaming (less accurate but dynamic)• Vertex Averaging (more accurate and static)

UC 2007 Tech SessionsUC 2007 Tech Sessions 2929

Data Collection Techniques

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 30

•Do you understand Sticky Keys?•Have you used appropriate colours and line thicknesses?

•Is your device locked?•Don’t you pick on me! (Avoid clicking on the map)•The art of using a stylus•Slow down and smell the flowers!

UC 2007 Tech SessionsUC 2007 Tech Sessions 3030

ArcPad Tips and Tricks

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 31

Mobile GIS

ArcPad Orientation Demonstration

Mobile GIS

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Slide 32

Thank you

Mobile GIS Specialistpvanjaarsveld@gims.com

(011) 238 6300