<html><head><style>body{font-family:Verdana,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Hi Mike - missed the water body shapefile first time around!</div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Good and worthwhile assessment of the quality of the shapefiles. I was initially really excited, thinking we had a definitive set of boundaries for Tanzania. You're right, this is of real concern if the errors continue down to the ward level!</div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">This is another good example of why we need a national SDI programme. Is anyone aware of any advances in NSDI? The last news article I can find is from 2011: http://www.ippmedia.com/frontend/index.php?l=28226</div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">There is a 2007 concept document: http://www.topocarto.co.tz/downloadfiles/survey/DRAFT%20NATIONAL%20SPATIAL%20DATA%20INFRASTURE-3.pdf</div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">The Survey and Mapping Division should theoretically be the custodian of definitive boundaries - does anyone know if they can provide digital versions of their basic admin data?</div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Verdana,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Cheers - Howard</div><div id="bloop_sign_1397642993514596096" class="bloop_sign"><p></p></div> <br><p style="color:#000;">On 16 April, 2014 at 12:36:06, Mike Shand (<a href="mailto:mike.shand@glasgow.ac.uk">mike.shand@glasgow.ac.uk</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div text="#000000" bgcolor="#FFFFFF"><div></div><div>
<title></title>
Hi Howard,<br>
<br>
The Download zip file from NBS has 4 shapefiles - region; district;
international bdy; and <b>water body</b>.<br>
<br>
My observations on the shapefiles are that:<br>
(a) The Water Body and the Districts shapefiles fit to each
other.<br>
(b) The Regions and the International Boundary shapefiles fit to
each other.<br>
There is a 250-300m shift between (a) and (b).<br>
It does not appear to be a simple projection shift.<br>
This then poses the question - which pair of shapefiles are correct
- I have overlaid them all on Google and OpenStreetMap and cannot
say which if any are correct.<br>
<br>
My observations regarding inconsistencies with the coastline and
lakes are that:<br>
(1) Region and District shapefiles follow the lakeshore for
Victoria but the lake centreline for Tanganyika and Nyasa.
For statistical mapping purposes the boundaries would normally
follow the edge of water bodies.<br>
(2) the northern lakeshore for Nyasa follows the coastline but the
southern boundary follows the centreline.<br>
(3) There is also an error in the most northern section of Lake
Nyasa on the Malawi side.<br>
(4) I have concerns about the interpretation of the coastline
around the Rufiji delta, Kilwa and Mafia with regards to the
alignment with the high/low water mark and tidal areas.<br>
(5) on the Water Body shapefile a number of large and small islands
are missing in Lake Victoria e.g. Ukerewe<br>
(6) there inconsistencies in dealing with internal lakes and
administrative boundaries e.g. Lake Rukwa and Lake Natron, Kagera
and their delineation. Some small lakes are included some are
not.<br>
(7) there is a strange spike on the coastline south of
Mtwara.<br>
<br>
I think the NBS and/or Survey & Mapping Division should work
together and take responsibility for addressing these issues which
are major problems for GIS users. If we as users all take it
upon ourselves to fix these issues independently we will have a
real problem resulting in many differing datasets circulating
around the users of Tanzania GIS data.<br>
<br>
It is projected that the Ward and Village boundaries will be
released by NBS this year, if these issues persist with these
datasets then as users we will continue to have a real
problem. Do we have any subscribers from NBS or SMD
that could take forward these data quality issues.<br>
<br>
Regards,<br>
Mike<br>
<br>
<div class="moz-text-html" lang="x-western">
<div><font color="#999999" face="Arial" size="2">************************************<br>
Mike Shand,<br>
FRSGS; MAppSci; FBCartS,<br>
Honorary Research Fellow<br>
(GIS Cartographer / Consultant)<br>
Geographical & Earth Sciences,<br>
University of Glasgow,<br>
Scotland, U.K. <br>
Tel: +44 (0)141 330 4780<br>
E-mail: <a href="mailto:Mike.Shand@glasgow.ac.uk">Mike.Shand@glasgow.ac.uk</a></font></div>
<div><font color="#999999"> </font></div>
<div><font face="Arial" size="2"><font color="#999999">Hon.
Secretary: Society of Cartographers <a href="http://www.soc.org.uk/">http://www.soc.org.uk/</a><br>
HOME PAGE & TANZANIA Links: <a href="http://web2.ges.gla.ac.uk/%7Emshand">http://www.gla.ac.uk/schools/ges/staff/mikeshand/</a></font><br>
************************************</font></div>
<pre wrap="">The University of Glasgow, charity number SC004401
</pre></div>
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