This document provides an introduction to an open source GIS course for Irish archaeology. It defines GIS as a system to store and analyze geographic data, and notes it can be used for archaeology, mapping, and other spatial applications. It outlines common GIS data formats, including vector files like points, lines and polygons to represent archaeological sites, roads and boundaries, and raster files like scanned plans, aerial images and elevation models. Finally, it introduces the GDAL and OGR libraries for working with raster and vector geospatial data formats in open source GIS.

1. Introduction to Open Source Gis Course
for Irish Archaeology
Institute of Archaeologists of Ireland – CPD Course
Saturday 12th of November 2011
Gianmarco Cattari
www.you-gis.com
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2. GIS = Geographic Information System
 A Geographic Information System (GIS) is designed
to capture, store, manipulate, analyze, manage and
present all types of geographically referenced data.
 In the simplest terms, GIS is the merging of
cartography, statistical analysis, and database
technology.
 GIS may be used in archaeology, geography,
cartography, remote sensing, land surveying, public
utility management, natural resource management,
precision agriculture, photogrammetry, urban
planning, emergency management, environmental
contamination, landscape architecture, navigation,
aerial video and localized search engines.
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3. GIS data formats
 VECTOR GRAPHICS is the use of geometrical
primitives such as points, lines, curves, and shapes
or polygon(s), which are all based on mathematical
equations, to represent images in computer graphics.
 Vector graphics formats are complementary to
RASTER GRAPHICS image is a data structure
representing a generally rectangular grid of pixels, or
points of color, viewable via a monitor, paper, or other
display medium. Raster images are stored in image
files with varying formats.
 Vector graphics are stored as mathematical
expressions as opposed to bit mapped graphics
which are stored as a series of mapped 'dots', also
known as pixels (Picture cells).
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4. Vector files
Points Lines Polygons
Archaeological National
Town
Sites Roads
Boundarie
s
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5. Combination
of vector files
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6. Raster Data
Scanned Archaeological Plan Orthoimage Lidar Survey
6 Digital Elevation Model (DEM) Hillshade Model Aerial Photo

7. GDAL and OGR libraries
 The Open Source Geospatial foundation
 The GDAL (Geospatial Data Abstraction Library) is a
translator library for raster geospatial data formats
that is released under Open Source license by the
Open Source Geospatial Foundation. GDAL raster
format list
 The related OGR (OpenGIS Simple Features
Reference Implementation) library (which lives
within the GDAL source tree) provides a similar
capability for simple features vector data. OGR
vector format list
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8. www.you-gis.com
...for your attention
Maps courtesy of Irish Archaeological Field
School, IAFS
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