From Geographic Information to GIS - Part II: Processing Data

From Geographic Information to GISGetting the Map into the computer

Part II: Processing Data

Arnaud Vandecasteele

Memorial Univ. of Newfoundland,

Canada

3/02/2013

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Outline

Introduction

1 – Processing GPX Data

2 – Using GPX Data in GIS

3 – Using GPX Data in VGI

Conclusion

Introduction

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Objectives

Introduction

Methods and tools to process your GPX data

Integration of your GPX inside a GIS platform

Integration of your GPX inside a VGI platform

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I – Processing GPX data

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GPX, or GPS eXchange is a light-weight XML data format for the interchange of GPS data (waypoints, route and tracks)

<?xml version="1.0" encoding="UTF-8" standalone="no" ?><gpx ...>

<metadata> ... </metadata>

</gpx>

<wpt lat="#" lon="#"> <ele>#</ele> <name>...</name> …</wpt><wpt lat="#" lon="#"> …</wpt>

<trk> <trkseg> <trkpt lat="#" lon="#"> <ele>#</ele> </trkpt> <trkpt ...> …. </trkpt> </trkseg></trk>

Metadata

Data

Track Waypoint

GPX File.Gpx

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

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Analysing GPZ File - Metadata

<?xml version="1.0" encoding="UTF-8" standalone="no" ?><gpx ...

creator="eTrex 20" version="1.1" ...<metadata>

<link href="http://www.garmin.com"> <text>Garmin International</text></link><time>2013-02-05T12:03:16Z</time>

</metadata><trk> <name>MMMMMMMK3 08:33:02</name> <trkseg> <trkpt lat="47.5536662433" lon="-52.7926951088"><ele>169.81</ele><time>2013-02-05T11:44:41Z</time></trkpt> <trkpt lat="47.5540290959" lon="-52.7929564565"><ele>168.37</ele><time>2013-02-05T11:44:50Z</time></trkpt> <trkpt lat="47.5542206224" lon="-52.7935003582"><ele>167.41</ele><time>2013-02-05T11:44:57Z</time></trkpt> <trkpt lat="47.5541830715" lon="-52.7945925202"><ele>167.41</ele><time>2013-02-05T11:45:07Z</time></trkpt> <trkpt lat="47.5543716643" lon="-52.7948338352"><ele>166.93</ele><time>2013-02-05T11:45:15Z</time></trkpt>

</trkseg></trk>

</gpx>



http://www.garmin.com/

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<?xml version="1.0" encoding="UTF-8" standalone="no" ?><gpx ...

creator="eTrex 20" version="1.1" ...<metadata>

<link href="http://www.garmin.com"> <text>Garmin International</text></link><time>2013-02-05T12:03:16Z</time>

</metadata><trk> <name>MMMMMMMK3 08:33:02</name> <trkseg> <trkpt lat="47.5536662433" lon="-52.7926951088"><ele>169.81</ele><time>2013-02-05T11:44:41Z</time></trkpt> <trkpt lat="47.5540290959" lon="-52.7929564565"><ele>168.37</ele><time>2013-02-05T11:44:50Z</time></trkpt> <trkpt lat="47.5542206224" lon="-52.7935003582"><ele>167.41</ele><time>2013-02-05T11:44:57Z</time></trkpt> <trkpt lat="47.5541830715" lon="-52.7945925202"><ele>167.41</ele><time>2013-02-05T11:45:07Z</time></trkpt> <trkpt lat="47.5543716643" lon="-52.7948338352"><ele>166.93</ele><time>2013-02-05T11:45:15Z</time></trkpt>

</trkseg></trk>

</gpx>

What does this file tell us?

GPS Metadata

GPS Positions: Tracks

Analysing GPZ File - Metadata



http://www.garmin.com/

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GPX Visualisation

GPX Path

Elevation Profil



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GPX Visualisation

Specific PointInformation



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GPX Cleaning Manual Process

Potential error



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GPX Cleaning Manual Process



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GPX Cleaning Automatic Process



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e.g., KML, SVG, export

GPX Export



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First GPX

GPX Comparison, two GPS same place/time

Second GPX



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How to get accurate GPS positions?

Geometric Dilution of Precision (GDOP) :● Horizontal DOP (HDOP)● Vertical DOP (VDOP)● Positional DOP (PDOP)● Time DOP (TDOP)

Good GDOP

Bad GDOP


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II - Using GPX in GIS

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Conversion Process

Example with QGIS → Add Vector Layer


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Example with QGIS → Save as ...

Conversion Process


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Conversion Process

From GIS to internet


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From GIS to internet

Conversion Process


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Data Storage

A focus on Postgis @ http://postgis.net/


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Data Storage

What is PostGIS ?

Postgis is a spatial extension for Postgresql:● Provides Spatial Data Type ● Provides Spatial Indexing ● Provides Spatial Functions


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PostGIS DataTypes

Point Line LinearRing Multypolygon

+ MultiLine, MultiPolygon, GeometryCollection...

Data Storage


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PostGIS Spatial Indexing

R-treeQuadtreeGrid-based

Data Storage


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PostGIS Spatial Functions

ConstructionSerialisationPredicatesAnalysisAccessorsBuildersAggregates

Example:ST_Simplify(geom, tolerance)

1

Data Storage

2

3


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Data Storage

Using GIS and PostGIS

1 2Import your data into PostGIS Load your data into QGIS


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Using GIS and PostGIS

Data Storage


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III – Processing GPX in VGI

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Geographic data● For driving, riding, walking, boating, skiing, hiking, anything ● Free (ODBL License)● Wiki-like editing

+

=

OpenStreetMap

What is OpenStreetMap?

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Volunteered Geographic Information


What not just use commercial map providers?

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More coverage, update, attributes

OpenStreetMap

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OpenStreetMap


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OpenStreetMapOpenStreetMap

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OpenStreetMap

Source : http://www.geofabrik.de

Paris : Aout 2006Paris : Aout 2006

Paris : Décembre 2010Paris : Décembre 2010


http://www.geofabrik.de/

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Source :http://www.flickr.com/photos/itoworld/


OpenStreetMap

Humanitarian OSM

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Contributing to OpenStreetMap


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Nodes lines Polygon

Relations

Geometric Objects Conceptual Objects

Relations

OpenStreetMap Objects


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higway = Tert iary

higway = trunk

higway = Residential

higway = trunktunnel = yes

leisure = garden

building = yestourism = museum

higway = secondary

OpenStreetMap Objects


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Field Papers@ http://fieldpapers.org

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Adding data to OpenStreetMap


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Missing roads ?


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Creation of the missing object



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Results

Before


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After

Results


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Questions ?

Arnaud Vandecasteele@geotribu

From Geographic Information to GIS - Part II: Processing Data

Technology

gisusing gpx

gpx data448

gpx data integration

tracks gpx file metadata

geographic data

data trackwaypoint

vgi conclusion248introduction

vgi platform348introduction