UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 UNSD Workshop Pieter van Jaarsveld Mobile GIS Specialist An Overview to a professional GPS/Mapping collection solution UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Survey Recreational GPS users? In-car navigation users? Capturing GPS data in the field for GIS use? Plan to in the next year? UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

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

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 What is GPS? Global Positioning System Where on earth am I ? Constellation of satellites Handheld devices Various Applications Accuracy UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 GPS in 5 Basic Steps 1 Correct for Atmosphere & Ionosphere Differential Corrections 4 3 Trilateration using speed of light Accurate clocks are required 2 Use ephemeris for satellites’ location 5 UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

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

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Control Segment Provides worldwide coverage and control 365/24/7 Master Control station Colorado Four support stations Hawaii Kwajalein Diego Garcia Ascension Island OK so lets take a slightly more detailed look at the control segment. It provides worldwide coverage and control 24/7 356 days of the year. This continual monitoring is critical to ensuring each satellite is positions correctly and its health is monitored and reported to the user segment. There is a master control station in Colorado and four support stations distributed through out the major oceans maintaining contact with each satellite for each quadrant of the earth. UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Space Segment GPS satellite constellation 24 satellites Replenishment occurring Satellite design Lifetime 7.3 years 16 satellites over 9 years old The space segment itself consists of 24 operation satellites. At all times there are at least three satellites in reserve. The reserve satellites are used to replace any operation satellite that becomes un-healthy. Replenishment of the satellites is continually occurring to maintain the constellation and ensure accurate positioning is visible in the future. Current lifetime of the satellites in orbit is 7.3 years, far beyond their expected lifetimes. There are 16 over 9 nine years old. UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 User Segment Equipment produced by Military and Private companies Receives signal and computes Position Time Velocity The user segment consists of both military and private users. It is important to note there are two separate signals, one for military operations and another for commercial sector. I’m only going to focus on the commercial sector today… The uses of GPS in the user segment are very diverse and basically touch on all aspects of our life from handling financial transactions through to landing the planes and of course managing our geographic information!!! UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

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 The basis of GPS is "triangulation" from satellites. To "triangulate," a GPS receiver measures distance using the travel time of radio signals. To measure travel time, GPS needs very accurate timing which it achieves with some tricks. Along with distance, you need to know exactly where the satellites are in space. High orbits and careful monitoring are the secret. Finally you must correct for any delays the signal experiences as it travels through the atmosphere. In a sense, the whole thing boils down to those "velocity times travel time" math problems we did in high school. Remember the old: "If a car goes 60 miles per hour for two hours, how far does it travel?" Velocity (60 mph) x Time (2 hours) = Distance (120 miles) In the case of GPS we're measuring a radio signal so the velocity is going to be the speed of light or roughly 186,000 miles per second. The problem is measuring the travel time. The timing problem is tricky. First, the times are going to be awfully short. If a satellite were right overhead the travel time would be something like 0.06 seconds. So we're going to need some really precise clocks. We'll talk about those soon. But assuming we have precise clocks, how do we measure travel time? To explain it let's use a goofy analogy: Suppose there was a way to get both the satellite and the receiver to start playing "The Star Spangled Banner" at precisely 12 noon. If sound could reach us from space (which, of course, is ridiculous) then standing at the receiver we'd hear two versions of the Star Spangled Banner, one from our receiver and one from the satellite. These two versions would be out of sync. The version coming from the satellite would be a little delayed because it had to travel more than 11,000 miles. If we wanted to see just how delayed the satellite's version was, we could start delaying the receiver's version until they fell into perfect sync. The amount we have to shift back the receiver's version is equal to the travel time of the satellite's version. So we just multiply that time times the speed of light and BINGO! we've got our distance to the satellite. That's basically how GPS works. Only instead of the Star Spangled Banner the satellites and receivers use something called a "Pseudo Random Code" - which is probably easier to pronounce and sing than the Star Spangled Banner. UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Sources of Positioning Error Ionosphere and Atmospheric delays Satelite and receiver Clock Error Multipathing Dilution of Precision Receiver Issues Selective Availability Like any system there are always errors to account for…so what are the core error sources in GPS. Errors can be grouped into the six classes: 1)   Multipath--Errors caused by reflected signals entering the receiver antenna 2)   Ionosphere--Errors in the corrections of pseudorange caused by ionospheric effects 3)   Ephemeris data--Errors in the transmitted location of the satellite 4)   Satellite clock--Errors in the transmitted clock 5)   Receiver issues – which really boil down to hardware and positioning engine implementations UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Differential GPS 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 Data Collector Base UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Differential Correction Red = Uncorrected GPS Green = GPS after differential correction UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Selecting a GPS Recreational versus Professional GPS Accuracy Tens of meters versus sub meter GIS data integration Format conversion Attribute collection Customised forms, business rules UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

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

Data Collection Workflow (server to server) Desktop Mobile Desktop Server Export to PGDB Check out Copy to device Copy to Desktop Check In Post process Import to Enterprise Data validation Enterprise Geodatabase ArcPad UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Data - things to remember 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. UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 UC 2007 Tech Sessions 17 17

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

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

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 ArcPad Benefits Streamlines 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 Traditionally, paper maps are what used in the field by mobile workers. Field edits were performed using sketches and notes on these paper map. Once back in the office, these field edits were then manually entered into the GIS database. The ArcPad workflow as outlined before has enormous productivity gains - it eliminates the major portion of office work previously required to integrate the field data with the enterprise GIS database. But, more importantly, it significantly improves the accuracy of the field GIS data, and consequently improves the accuracy, currency, and integrity of the enterprise GIS database - resulting in more accurate and current data for analysis and decision making. This is a major benefit of mobile GIS applications. UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

ArcPad Functionalities Improved performance Enhanced editing tools Snapping Undo offsets for points, lines, polygons repeated features segmented line features Camera and rangefinder support Improved symbology and labeling Support for Graphics layer for redlining or mark-up Import/export tools for ArcGIS Customization wizard for creating custom forms ArcPad 7 offers enhancements in the areas of performance, ease of use, productivity, enterprise GIS integration and customization. New features include Quicker access and loading of spatial data Advanced editing tools, including offsets, repeated attributes, segmented line features, snapping, and undo Support for ArcGIS symbology and style sheets - Maps look the same in ArcMap and ArcPad and more labeling options Integrated support for rangefinders and digital cameras Support for freehand marking and taking notes on maps ArcPad 7 includes additional tools for ArcMap which are automatically installed with ArcPad. These new tools allow you to: • Extract data for use with ArcPad 7 and/or check data out of a geodatabase for editing. • Export symbology for selected shapefiles into ArcPad Layer files. • Export/import an ArcGIS Graphics Layer to/from an ArcPad Graphics layer. • Export ArcGIS styles to an ArcPad style. Simple form customization within ArcPad UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

ArcPad Functionalities Significant 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) ArcPad 7 offers enhancements in the areas of performance, ease of use, productivity, enterprise GIS integration and customization. New features include Quicker access and loading of spatial data Advanced editing tools, including offsets, repeated attributes, segmented line features, snapping, and undo Support for ArcGIS symbology and style sheets - Maps look the same in ArcMap and ArcPad and more labeling options Integrated support for rangefinders and digital cameras Support for freehand marking and taking notes on maps ArcPad 7 includes additional tools for ArcMap which are automatically installed with ArcPad. These new tools allow you to: • Extract data for use with ArcPad 7 and/or check data out of a geodatabase for editing. • Export symbology for selected shapefiles into ArcPad Layer files. • Export/import an ArcGIS Graphics Layer to/from an ArcPad Graphics layer. • Export ArcGIS styles to an ArcPad style. Simple form customization within ArcPad UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

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

Streaming and Averaging number of incoming GPS position coordinates that ArcPad uses for calculating an average coordinate Streaming Position 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 UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 GPS Preferences Quality Minimum and maximum values can be predefined Can be made compulsory to ensure data integrity Warning and Alerts Visual and Audio alerts Constantly warns the user if not complying to presets Will inform the user of GPS status Can be annoying Can be switched off UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Editing using the GPS Firstly, make layer editable (one point, line, polygon, at a time) Then select feature type Then select GPS capture tool UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Ensuring data quality Elevation Mask Default 15 No. of Satellites Min of 4 SV’s SNR Signal to Noise Ratio High = Accurate Low = Productive DOP SV Geometry High = BAD Low = GOOD UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 UC 2007 Tech Sessions 27

ArcPad with other devices ArcPad 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 UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007

Data Collection Techniques 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) UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 UC 2007 Tech Sessions 29

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 ArcPad Tips and Tricks 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!  UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 UC 2007 Tech Sessions 30

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

UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007 Thank you Mobile GIS Specialist pvanjaarsveld@gims.com (011) 238 6300 UNSD - Mapping and Sensus Workshop: Lusaka, Zambia 8 -12 October 2007