GPS one day training

A quick and dirty introduction to GIS and spatial data collection

Dr. Catherine Pfeifer

Objective of the day

You will know

● How a GPS works

● About diversity of GIS software to map your own data

● The advantages and disadvantages of different GIS software

You will be able

● to set a GPS right

● To collect data point and track your path with a GPS (to calculate area)

● To map your own data in a GIS software

● To choose the GIS software that suits your situation and needs

Program of the day

● Playing a game to know each other ● Theoretical introduction to GIS● Setting a GPS right● How to collect points, lines (tracks), areas● Downloading your data● GIS software (Arc, QGIS, google earth)● Map your data in your favorite GIS software● Discuss your work and the difference between the

softwares

Program of the day

● Playing a game to know each other ● Theoretical introduction to GIS● Setting a GPS right● How to collect points, lines (tracks), areas● Downloading your data● GIS software (Arc, QGIS, google earth)● Map your data in your favorite GIS software● Discuss your work and the difference between the

softwares

Program of the day

● Playing a game to know each other ● Theoretical introduction to GIS● Setting a GPS right● How to collect points, lines (tracks), areas● Downloading your data● GIS software (Arc, QGIS, google earth)● Map your data in your favorite GIS software● Discuss your work and the difference between the

softwares

A theoretical introduction to GIS

● What is GIS and spatial data?● What is a coordinate system and why is it

important?● How to collect data? How does a GPS work?● How to represent spatial data? An overview of GIS

softwares

What is GIS ?

Spatial data as representation of the real world

● Spatial layer represents one information that can be overlaid for analysis

● Two types of data – Vectors (points,

lines, polygons)

– Grids

A theoretical introduction to GIS

● What is GIS and spatial data?● What is a coordinate system and why is it

important?● How to collect data? How does a GPS work?● How to represent spatial data? An overview of GIS

softwares

Coordinate systems

What is a coordinate system?

A coordinate system is a reference system used to represent the locations of geographic features, imagery, and observations such as GPS locations within a common geographic framework.

Coordinate system types : • Geographic coordinate system

(global/spherical) • Projected system (“making the world flat”)

Map projection

UTM projection

‘pseudocylindrical’ conformal projection (it preserves shape)

Concepts linked to coordinate system

● Datum : assumed shape of the earth ● Projection : none = geographic coordinate system

otherwise method applied for “flattening the world” (example Mercator UTM)

● Coordinate format – Degree minutes seconds, degree minutes, decimal

degrees (geographic coordinates)

– Meters, kilometers (projected coordinates)

Internationally used settings

Each country has national standards, but the international standard is often default in many software.

● Datum :WGS 84

● Projection

– None for geographic

– UTM (use sheet 37 N for Ethiopia)

– (the national projection for Ethiopia is Adindan but we recommend to use international standards)

● Coordinate format

– Decimal degrees (geographic)

– Meter (projected)

What to keep in mind

● GPS work generally with unprojected data● If you are not sure what you are doing use

international standards● Always write down what settings you used● Ask a GIS specialist before doing “strange things”

like re-project or assign projection

A SMALL MISTAKE MAY LEAD TO DAYS OF WORK FOR A GIS SPECIALIST AND IN THE WORST CASE YOUR DATA IS USELESS

A theoretical introduction to GIS

● What is GIS and spatial data?● What is a coordinate system and why is it

important?● How to collect data? How does a GPS work?● How to represent spatial data? An overview of GIS

softwares

Geographical Positioning System

● Uses satellites to locate the receiver

● With smartphone hybrid systems (mobile and wiki network)

What data can you collect with a GPS?

● Points (farmer's homestead)● Tracks (lines, path traveled)● Areas (farmer's field) works only on expensive

Garmin GPS

Settings in your GPS

● Must match with the settings you are going to use in the GIS software

● Advice use WGS84 unprojected, coordinate in decimal degrees

– All google geo-application use these settings

– It is also default in QGIS

A theoretical introduction to GIS

● What is GIS and spatial data?● What is a coordinate system and why is it

important?● How to collect data? How does a GPS work?● How to represent spatial data? An overview of

GIS softwares

GIS software

● Full GIS solution– ArcGIS (can be enhanced with DNR garmin)

– QGIS (with GPS plug-in)

– Google earth (with GPS feature on windows)

● GPS data download software– DNR garmin (can be linked with GPS)

– Many others

● Others– Drivers for gps

– Android tracking program (mytracks)