GIS data North Africa
What is a GIS?
A geographic information system (GIS) is a computer-based tool for mapping and analyzing data. GIS technology integrates common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps. Mapmaking and geographic analysis are not new, but a GIS performs these tasks better and faster than do the old manual methods.
Maps have a special place in GIS. The process of making maps with GIS is much more flexible than are traditional manual or automated cartography approaches. It begins with database creation. Existing paper maps can be digitized and computer-compatible information can be translated into the GIS. The GIS-based cartographic database can be both continuous and scale free. Map products can then be created centered on any location, at any scale, and showing selected information symbolized effectively to highlight specific characteristics.
In today's geological research and exploration, information comes in many different ways, including e.g. paper maps, digital data, publications, internal company reports and regional consultants syntheses. Information can be overwhelming and the need for timely evaluations and decisions calls not only for innovative ways to access accurate, up-to-the minute information, but also tools to help present the information in useful ways.
A geographic information system or GIS allows you to bring all types of data together based on the geographic and locational component of the data. But unlike a static paper map, GIS can display many layers of information. This allows to integrate, visualize, manage, solve, and present the information in a new way. Relationships between the data will become more apparent and the data will become more valuable. Many authors of geological maps and reports today offer their reports in GIS format, which facilitates integration of data from different data sources.
Advantages of GIS for geological exploration and research
- Comprehensive data archive.
- Fast overview about what data is available.
- Once digitised, data quality does not deteriorate (unlike some old paper data).
- All data in the same, user-friendly format. This allows quick access and easy comparison of datasets.
- Output of maps for presentations and reports.
- GIS is a tool which facilitates comprehensive study of complex data and stimulates ideas in exploration.
Software and Hardware
Common GIS softwares are from ESRI (ArcView and, more complicated, ArcInfo) and MapInfo. A free GIS is GRASS. In terms of hardware, a modern PC with at least 128 MB RAM and several GB of space on your harddisk is all you need to get started.
North Africa GIS data
The listing below contains sources for North African data, that can be either (1) freely downloaded from the web or (2) purchased from specialist companies. Of course, own data can be also converted into GIS format (3). As the author (SL) has worked with ArcView in the past, most of the data listed is in this format or can be easily converted into it. If you know any other data sources or want to share some of your data, please contact us (firstname.lastname@example.org) for inclusion in this list. The working group of Prof. List (Free University Berlin) has been working on geological GIS projects in Egypt and other regions for several years. If you want to get in contact with other people using GIS in the Middle East and North Africa join the GIS-Cafe, a discussion forum about all aspects of GIS in the Middle East / North Africa. A free monthly newsletter about African GIS is published by GSDI.
1) Free Data
- Geological base map (based on the Unesco map) and geological provinces/basins of Africa in ArcInfo/ArcView format, provided by the US Geological Survey (description).
- The sites of the Deep Sea Drilling Program (DSDP) and the Ocean Drilling Program (ODP) are available for download from the ODP website.
- Towns, roads, drainage patterns etc. from every North African country is available for free download from the GIS Datadepot (http://www.gisdatadepot.com), based on the 'Digital Chart of the World'.
- Data tables containing several 10.000s of place names in txt-format for each of the North African countries can be freely downloaded from the National Imagery and Mapping Agency (USA). The tables have also been converted into ArcView GIS formats and the files for Morocco, Algeria, Tunisia, Libya and Egypt can be downloaded from here. Also available are two ArcView files (download 1 and 2 from here) containing locations of mineral mines, oil- and gas fields and pipelines.
- Digital elevation model data. Free download from the web in 1km grid (http://www.cuug.ab.ca/~fortuned/dew.html). Also have a look at Getech's download access site. Higher resolution data can be purchased. Note that ArcView only allows to view the digital elevation data; for querying height information on a pixel-by-pixel basis ArcInfo or the Spatial Analyst Extension for ArcView is needed.
- USGS World Petroleum Assessment 2000 - GIS files download.
- Free satellite images: See listing below.
2) Data for purchase
· LYNX Information Systems offers complete GIS packages with data for hydrocarbon exploration for various North African countries, e.g. Algeria, Libya, Egypt.
· Deloitte PetroView database for North Africa
· LeadDog Consulting street and road GIS Data North Africa and Worldwide
· Topographic maps of North Africa (Russian Military Series) 1:200.000 can be georeferenced for ArcView by GeoPubs - Worldwide Geodata. Other georeferenced topographic maps can be purchased from Land Info.
· A geological map of North Africa (including faults, drainage, lineaments, roads etc.) in ArcView format, based on the UNESCO map, can be purchased from Geologic Data Systems. Note however, that the geological base map of the above-mentioned package (without faults etc.) can also be downloaded for free from the US Geological Survey.
· A CD with worldwide country boundaries, low-resolution composite satellite image and other worldwide data is available from ESRI Data & Maps.
· A vatiety of GIS data packages is offered by ComputaMaps.
· ArcView GIS Synthesis of the petroleum basins of North Africa. Multi-client project by the Energy and Geoscience Institute at the University of Utah (EGI).
· Topographic map of Africa, 1:500.000 (Russian Military Series) in georeferenced digital format (GIF, PNG formats) (by Sahara-info); georeferenced topographic map of North Africa 1:500.000, apparently based on flight charts (by Fugawi).
· Georeferenced satellite images: See listing below.
· GIS data for North Africa and Arabia by CEDARE.
3) Produce your own GIS data
It is relatively easy to produce your own GIS-format point theme data, e.g. locations of field sections and field photographs, camps, GPS waypoints acquired during fieldwork, sample tables etc. Generation of your own GIS-format map data requires greater skills but learning this technique is certainly worth the effort.
If you are looking for help with transforming your North African data into a GIS-format you should speak to a specialist service company, e.g. LYNX Information Systems (London).
If you are based in Egypt and want to learn GIS contact the Information Technology Institute in Cairo who offer special GIS training courses.
Satellite Images North Africa
1) Free Images
- NASA MrSid-satellite images, high resolution, available for most landparts of the world, free download, also download free MrSid Viewer; all images are georeferenced and can be used in ArcView (activate MrSid extension, projection needs to be UTM with the local UTM zone). HIGHLY RECOMMENDED
- Free satellite images (worldwide, sorted by country), by NASA (Visibleearth)
- Landsat images for free download from sahara-info.ch for Egypt, Libya and Tunisia.
- Free satellite images (worldwide) from ComputaMaps
- Satellite images of Cairo and Asyut (zoomable! download: 20US$) from TerraServer.com.
- Earthrise: Photos taken by astronauts out of the windows of the Space Shuttle, including many covering North Africa.
- Earth View
- Online Landsat TM images at Cornell University from northern Algeria and Morocco.
- Tifernine Dune Field, southernmost part of the Grand Erg Oriental (Algeria) (item 3 on link page)
- Gulf of Aqaba / Sinai Peninsula (Egypt)
- NASA Astronaut-acquired satellite images, incl. Morocco, Algeria, Libya, Egypt
2) Images and interpretation services for purchase
- IKONOS 1m-resolution satellite images of North Africa and areas in Eurasia
- Satellite mapping projects for hydrocarbon exploration by NPA. Includes thermal basin screening/seepage studies, structural interpretation of satellite images and other techniques. Projects in all North African countries.
- Regional Landsat TM mosaic North Africa, by Infoterra (formerly NRSC) who also sell other (georeferenced) satellite images from the region.
- NASA Scientific Data Purchase
- Multi satellite images from Eurimage (special discount on data for business development and research initiatives).
- Spot Images
An excellent web-based GIS on North African geology and geophysics (covering also the rest of the world) is provided by Cornell University. The Cornell GIS is very easy to use and includes a variety of geographical elements such as country borders, towns etc., as well as key geological and geophysical properties, e.g. geological map, faults, mines (quarries) etc. The geographic boundaries of the resulting map can be freely chosen by the user. If you ever need a geological base map on which you want to plot your own data, this is the website to produce it quickly and painlessly (further information).
Interested in further information on GIS?
Here are some GIS websites which provide good starting points for further information on GIS:
- GIS Datadepot
- Geography Network
- Internet Guide to Geographic Information Systems