From Geographic Information to GISGetting the Map into the computer

Part II: Processing Data

Arnaud Vandecasteele

Memorial Univ. of Newfoundland,

Canada

3/02/2013

2/48

Outline

Introduction

1 – Processing GPX Data

2 – Using GPX Data in GIS

3 – Using GPX Data in VGI

Conclusion

Introduction

3/48

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

4/48

I – Processing GPX data

5/48

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

6/48

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>

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

7/48

<?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

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

8/48

GPX Visualisation

GPX Path

Elevation Profil

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

9/48

GPX Visualisation

Specific PointInformation

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

10/48

GPX Cleaning Manual Process

Potential error

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

11/48

GPX Cleaning Manual Process

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

12/48

GPX Cleaning Automatic Process

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

13/48

e.g., KML, SVG, export

GPX Export

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

14/48

First GPX

GPX Comparison, two GPS same place/time

Second GPX

Data Collection Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

15/48

Data Collection Process

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

Processing GPX Data Using GPX in GIS Using GPX in VGI

16/48

II - Using GPX in GIS

17/48

Conversion Process

Example with QGIS → Add Vector Layer

Processing GPX Data Using GPX in GIS Using GPX in VGI

18/48

Example with QGIS → Save as ...

Conversion Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

19/48

Conversion Process

From GIS to internet

Processing GPX Data Using GPX in GIS Using GPX in VGI

20/48

From GIS to internet

Conversion Process

Processing GPX Data Using GPX in GIS Using GPX in VGI

21/48

Data Storage

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

Processing GPX Data Using GPX in GIS Using GPX in VGI

22/48

Data Storage

What is PostGIS ?

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

Processing GPX Data Using GPX in GIS Using GPX in VGI

23/48

PostGIS DataTypes

Point Line LinearRing Multypolygon

+ MultiLine, MultiPolygon, GeometryCollection...

Data Storage

Processing GPX Data Using GPX in GIS Using GPX in VGI

24/48

PostGIS Spatial Indexing

R-treeQuadtreeGrid-based

Data Storage

Processing GPX Data Using GPX in GIS Using GPX in VGI

25/48

PostGIS Spatial Functions

ConstructionSerialisationPredicatesAnalysisAccessorsBuildersAggregates

Example:ST_Simplify(geom, tolerance)

1

Data Storage

2

3

Processing GPX Data Using GPX in GIS Using GPX in VGI

26/48

Data Storage

Using GIS and PostGIS

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

Processing GPX Data Using GPX in GIS Using GPX in VGI

27/48

Using GIS and PostGIS

Data Storage

Processing GPX Data Using GPX in GIS Using GPX in VGI

28/48

III – Processing GPX in VGI

29/48

Processing GPX Data Using GPX in GIS Using GPX in VGI

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

+

=

OpenStreetMap

What is OpenStreetMap?

30/48

Volunteered Geographic Information

Processing GPX Data Using GPX in GIS Using GPX in VGI

What not just use commercial map providers?

31/48

More coverage, update, attributes

OpenStreetMap

32/48

OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

33/48

OpenStreetMapOpenStreetMap

34/48

OpenStreetMap

Source : http://www.geofabrik.de

Paris : Aout 2006Paris : Aout 2006

Paris : Décembre 2010Paris : Décembre 2010

Processing GPX Data Using GPX in GIS Using GPX in VGI

35/48

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

Processing GPX Data Using GPX in GIS Using GPX in VGI

OpenStreetMap

Humanitarian OSM

36/48

Contributing to OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

37/48

Nodes lines Polygon

Relations

Geometric Objects Conceptual Objects

Relations

OpenStreetMap Objects

Processing GPX Data Using GPX in GIS Using GPX in VGI

38/48

higway = Tert iary

higway = trunk

higway = Residential

higway = trunktunnel = yes

leisure = garden

building = yestourism = museum

higway = secondary

OpenStreetMap Objects

Processing GPX Data Using GPX in GIS Using GPX in VGI

39/48

Contributing to OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

Field Papers@ http://fieldpapers.org

40/48

Contributing to OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

41/48

Adding data to OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

42/48

Adding data to OpenStreetMap

Missing roads ?

Processing GPX Data Using GPX in GIS Using GPX in VGI

43/48

Creation of the missing object

Adding data to OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

44/48

Adding data to OpenStreetMap

Processing GPX Data Using GPX in GIS Using GPX in VGI

45/48

Results

Before

Processing GPX Data Using GPX in GIS Using GPX in VGI

46/48

After

Results

Processing GPX Data Using GPX in GIS Using GPX in VGI

47/48

Processing GPX Data Using GPX in GIS Using GPX in VGI

48/48

Questions ?

Arnaud Vandecasteele@geotribu