1. Each entity of land has spatial information!
GIS
A Geographic Information System (GIS) can be defined as a set of hardware, software, data, methods and people.
Its aim consists in the management, display and analysis of geographically referenced information.
Each entity of land has spatial information!
GIS allows us to visualize, understand and discover the spatial relationships between geodata in form of maps, charts, reports, etc.

2. GIS

3. the position of things (coordinates)
GIS
What can we do with GIS?
We can map:
the position of things (coordinates)
the quantities of things (population)
the densities of things (density of population)
what happens inside a specific area
what is nearby within a specific distance
the evolution/change of phenomena
…and much more!

4. GIS
Spatial data links alphanumeric information with a specific location. Alphanumeric information is displayed in a computer screen in reference to the location of objects of the real world.
A data model in GIS is a mathematical construct for representing geographic objects or surfaces as data.
The vector data model represents geography as collections of points, lines, and polygons
The raster data model represents geography as cell matrices that store numeric values

5. GIS
Spatial information is displayed in a GIS using layers of spatial information. A layer could be based on a raster or vector data model.
The Raster data model is used mainly to represent continues features such as elevation, temperature or aerial and satellite images.
The Vector data model is generally used in order to represent discrete features (e.g. trees, roads, administrative boundaries, etc.).

6. GIS
Vector
Raster
Point
Polyline
Polygon

7. GIS
The vector data model

8. GIS Which is the most expensive? 2 1 3 Point 1 452896, 4785263 Point 2
456982,
Point 3
562841, ID
Name
Owner
Price 1
ABC
Joe 50 2
JKL
Bill 63 3
QWY
Mary 85
Which is the most expensive?

9. GIS 2 1 3
Point 1
452896,
Point 2
456982,
Point 3
562841, ID
Name
Owner
Price 1
ABC
Joe 50 2
JKL
Bill 63 3
QWY
Mary 85

10. GIS
Polyline
Vertex
Node

11. Polygon-polyline topology
GIS
Polygon-polyline topology
A polygon consists of lines, which consist of points, which consist of coordinates

12. GIS
Topological errors

13. GIS
Shapefile
The shapefile format is a popular geospatial vector data format for geographic information system (GIS) software. It is a proprietary format of ESRI.
Mandatory files 
.shp — shape format; the feature geometry itself
.dbf — attribute format; columnar attributes for each shape, in dBase IV format
.shx — shape index format; a positional index of the feature geometry to allow seeking forwards and backwards quickly
Other files 
.prj — projection format; the coordinate system and projection information, a plain text file describing the projection using well-known text format
.sbn and .sbx — a spatial index of the features
.shp.xml — geospatial metadata in XML format, such as ISO or other XML schema

14. Other vector formats DXF GML KML “coverage” GIS
Proprietary of AutoCAD, originally intended for technical drawings
GML
Geographical Markup Language, an open standard
KML
Keyhole Markup Language, also an open standard, made popular by GoogleEarth
“coverage”
Legacy format, proprietary, from ESRI, dating back to the ’80s

15. Spatial databases Geodatabase PostGIS SpatiaLite GIS
Proprietary of ESRI
Personal geodatabase
File geodatabase
Relational database
PostGIS
a spatial database extender for PostgreSQL object-relational database
SpatiaLite
A spatial extension to SQLite, a single-file portable relational database

16. GIS
Raster data
Raster data better describe continuous variables and phenomena
Satellite images, aerial photos, DEMs, etc.
Well suited for spatial analysis
Not well suited for cartography

17. GIS
The raster data model

18. GIS
Raster layers can store different data types (the values inside the cells)
Integer
byte (0-255, one cell = 1 byte)
example: most satellite images
x 2, signed or unsigned (one cell = 2 bytes)
example: DEMs
x 4, larger figures (one cell = 4 bytes)
can have attribute tables
Real (floating)
x 4 (one cell = 4 bytes)
example: vegetation indexes
x 8, higher accuracy, seldom used (one cell = 8 bytes)
The file size increases correspondingly, as well as the processing time

19. It is easy to convert most vector data to raster
GIS
It is easy to convert most vector data to raster
It is very hard (almost impossible) to convert decently raster data to vector

20. GIS raster file formats TIFF
more than a format, is a container
can accomodate multiple band, compressed or not
compression is usually lossless
GeoTiff include also georeferencing information
JPEG
created for storing picture using a highly efficient lossy compression
JPEG2000 can include georeferencing information and lossless compression
GRID
proprietary of ESRI
MrSID
patented, created for GIS, optimized for image viewing
compressed, lossless, not so common
Many other free or proprietary formats
QGIS relies upon the GDAL library for data reading/writing; for a full listing of formats that can be used by GDAL, see:

21. Where to find downloadable data
GIS
Where to find downloadable data
A categorized list of links to over 300 sites providing freely available geographic datasets - all ready for loading into a Geographic Information System
The Map Library is a source of public domain basic map data concerning administrative boundaries in Africa. The data is broken down into manageable chunks to make it easier to download for those with poor internet connections
The Open Source Geospatial Foundation (OSGeo), a good starting point
...and of course Wikipedia

22. GIS
Metadata is "data about data". Example: the card catalogue of a library.
Metadata provide information about one or more aspects of the data, such as:
means of creation of the data
purpose of the data
time and date of creation
creator or author of the data
physical location, e.g. on a computer network
standards used
Metadata is data. As such, metadata can be stored and managed in a database, often called a metadata registry or metadata repository.
They apply to many different sectors: geospatial metadata is a type of metadata that is applicable to objects that have an explicit or implicit geographic extent

23. Geospatial Metadata Standards:
GIS
Geospatial Metadata Standards:
ISO/TC 211 is a standard technical committee formed within ISO
task: covering the areas of digital geographic information and geomatics. It is responsible for preparation of a series of International Standards and Technical Specifications numbered in the range starting at 19101
ISO 19115: Geographic information – Metadata
It defines how to describe geographical information and associated services, including contents, spatial-temporal purchases, data quality, access and rights to use.
ISO Geographic information Metadata XML schema implementation
provides a spatial metadata XML (smXML) encoding, an XML schema implementation derived from ISO 19115
describe, validate, and exchange geospatial metadata

24. GIS

25. Get a full list at http://geonetwork-opensource.org/
GIS
The GeoNetwork opensource project is a free and open source cataloging application for spatially referenced resources.
It is used by large organizations to maintain and share a huge amount of information
Examples:
FAO
WFP
UNEP
CGIAR
WHO
Many other national and international portals
Get a full list at