Dewald Troskie nucleotic at gmail.com
Wed Nov 21 10:17:48 EST 2007

Hi All,
To answer some of Deon's questions:
1.     He should be able to read the MrSID images via GDAL on a Mapserver
WMS server by hooking into it from uDIG. It actually runs faster than what
ArcMap can read the files from disk or via AGX (ArcGIS         Explorer)
reading directly from the file.
2. This question can be a multi-headed monster. There are several options:


	You can install onto each machine and then connect to the central
datasource or web service you need (PostGIS, WMS, etc).

	Does the network involve virtual applicances or thin-clients? What
is the requirements of uDIG in the scope of what the client want's to do? If
virtualization is involved, installing it on each machine is not really an
option, and it would probally be best to run uDIG on a dedicated GIS Server
and have thin-clients / virtual connections use sessions on the machine.

3.     From what I gather reading the rest of the mail more indepth, the
best options for adding tracklog data (connecting mobile devices with a GPS)
would be through the GPSBabel library and importing the tracklog into the
database. Alternatively you could also interface the mobile devices from
uDIG via GPSBabel and utilise the data, tracklog and any attribute
information you may entered related to the spatial entities (land parcels,
As for the rest of Deon's mail, another Desktop GIS product that could be
used is Accuglobe 2007 (http://www.accuglobe.net/). I am not sure of the
extent of it's openness in relation to OSS, but I do know it is a free
product that just requires registration to download and use. I have been
following the product closely for the last 6 months, and suffice to say it
is very powerful, has multi-platform installers (Windows, Linux, Mac (I
think)), and is faster than both uDIG and qGIS at this stage. It also can
read various raster formats and vector data from PostGIS and shapefiles, and
from Personal Geodatabases (I haven't tried that one though).
Gavin, if Deon needs more info or help, he is welcome to contact me for
further assistance.
Dewald Troskie 
Systems Developer 
SWAP Mobile (Pty) Ltd. 
dewald at swapmobile.co.za 
(t) +27 (12) 460 4254 
(f) +27 (12) 460 5871 
(m) +27 (82) 615 0248 
176 Olivier Street | Brooklyn | Pretoria 
P.O. Box 340 | Groenkloof | 0027 | South Africa 



From: africa-bounces at lists.osgeo.org [mailto:africa-bounces at lists.osgeo.org]
On Behalf Of Gavin Fleming
Sent: 21 November 2007 04:12 PM
To: africa at lists.osgeo.org
Subject: [OSGeo Africa] FW: UDIG QUERIES

Hi all


I'm taking the liberty of forwarding a query from a new list member re UDig,
MrSID and mobile devices to the list hoping that some of you will be able to
help him.  




Deon's first questions:

1.	I need to read/convert MrSid aerial photos to display them in UDig
but have not been able to find anything on the website.  Any ideas? 

2.	 Someone has asked me regarding installing UDig on a network and I
said that it was the best to run individual software on every machine and
just point it to the database.  I have not had a comeback but was just

3.	We are thinking about linking some mobile devices to UDig but can't
seem to find anything in this regard on the web.  Any suggestions in this

My initial response:


1.	As far as I know, GDAL reads MrSID, which means one solution is to
serve the images through a MapServer WMS service. Then UDig or any other
client will be able to use them anywhere on the network. 

2.	I'd recommend installing UDig on each machine. Installing and
updating could be done over the network however. 

3.	What do you mean by 'linking mobile devices'? Perhaps you could be
more specific? 


Deon's subsequent query:

Hi Gavin


I have just been to an ESRI workshop where we discussed things like ArcPad
and other GPS devices linked to ArcGIS.  Obviously it was very detailed but
my query is much more general.   I would like to know what functionality
UDig has in terms of linking to handheld GPS's.  For instance we are
currently considering (how far we will get is another issue entirely)
sending our inspectors out with GPS's and having them log what they see in
terms of things like address,  business type, land use etc. and then linking
these coordinates to the specific land parcel.  The data could be very
specific i.e. an address number or perhaps even a longish comment.  I'm
sorry I cannot be more specific but we are basically brainstorming at this


I have played around with UDig as front-end for a while now and have found
it rather slow - is this the way it is or are there some tweaks that I could
try.  Obviously I'm comparing it with ArcGIS which is rather unfair but I'd
just like to know.  Are there any other desktops other than UDig and QGis
that I should try.  I'm not quite ready to go delving into the other
database-related stuff quite now and am specifically looking at smaller
desktop applications with some minor editing of mainly existing shapefiles
and using existing aerial photos as "backdrops" (therefore my query re MrSid
as our Tiffs are huge!  


As indicated before to a certain extent I'm not comparing apples with apples
but currently I am experimenting trying to utilize features that can/will
impress the unconverted and match or even improve ArcGIS functionality.  My
initial investigations seem to indicate that OSS might not be quite ready to
take over large organizational GIS functions (in Ekurhuleni Metro for
instance) but I am also very interested in the smaller users as we have many
requests from outside parties who need to read shapefiles but cannot afford
an ArcGIS kind of application.


I know I sound a little vague on many fronts (and I cannot be considered a
techie) but I will certainly be getting into contact you for more detailed
stuff later if you will indulge me.


Thanks again

Deon van der Linde

GIS Manager:  City Development

Ekurhuleni Metropolitan Municpality

011 398 2111


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