Digital Maps of South Africa

Roy Herold rherold@yahoo.com
Sun, 29 Apr 2007 11:34:35 PDT
Hi,

I'm copying a message from Derek Tribble that he posted to various 
succulent forums. I've tried them, and they work like a charm. I used a 
different viewer, however, called ExpressView that works as a plugin for 
IE or Firefox. It may be found at:

http://lizardtech.com/download/dl_options.php/…

Much easier than driving around the back roads of Cape Town to find the 
map office, and the digital versions take up a lot less room.

As an aside, Google Earth seems to be getting better and better with 
regards to navigating South Africa. For most of the country, the 
satellite photos went to hi-res about a year ago (meaning you can see 
individual cars on the roads). Recently a group called Tracks4Africa has 
added extensive road (and off road) information, right down to notes 
about locked gates and whatnot.

--Roy
Still in mourning for dozens of choice corydalis that were eaten by 
deer. And tulips. And crocus. Sigh.

_________________________________

Date: Sat, 21 Apr 2007 12:39:35 +0000
From: "derek tribble" <derek_tribble@hotmail.com>
To: cacti_etc@opus.scs.agilent.com
Subject: Digital Maps of South Africa
Message-ID: <BAY112-F3330C2808E00B5F8F470498B550@phx.gbl>


Hi Folks,

I thought you might like to know that digital maps for South Africa are
available for free via the Internet (thanks to the SA government's generous
policy of easy access to spatial data). It is great fun to pan along known
routes and re-live old memories! My thanks to Prof. Andy Young, who found
that individual maps can be downloaded from:

http://www.madmappers.com/

Visit Raster Maps in the top left and drill down to find free downloads for
South Africa. [Other countries and other map types are not free, as far as I
have explored].

However, the maps are in Mr Sid file format, so special software is needed
to view them. You will need software that understands the associated
metadata files, so that map images can be correctly "tiled" next to each
other, or other layers added over the top. The most commonly used free
viewer is ArcExplorer, but I use the free GIS (Geographic Info System)
software, DIVA-GIS ( http://www.diva-gis.org/ ) (for Windows only). This
powerful program can also plot species distribution maps and analyse them
against downloaded datasets (biomes,climate, geology, topography, etc.).
However, it does have a quirky user interface and is intended for use by
professional scientists - it comes without online help, just a .pdf manual!

The 1:250,000 maps (need 590Mb of free hard disk space) from the SA Chief
Directorate of Survey and Mapping will probably give enough detail for most
people. However, enthusiasts will be pleased to get access to the very
detailed 1:50,000 maps (2.5Gb for about half of the maps), but they take a
lot of downloading!

If you are already using digital maps, perhaps then you can help me! Are any
detailed digital maps available for Namibia? Anybody got SA geological
overlays? Vegetation overlays are freely available from SANBI's BGIS web
site: http://cpu.uwc.ac.za/ .

I am happy to help with any queries about using DIVA or these fascinating
digital maps.

Best wishes,
Derek Tribble,
London, UK


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