-------- Original Message --------
Subject:        Re: Free, open source map publishing tool - gdal2tiles
Date:   Mon, 19 Nov 2007 22:06:50 -0000
From:   Nicholas Verge <[log in to unmask]>
To:     Maps, Air Photo & Geospatial Systems Forum <[log in to unmask]>




>
> On Tue, 6 Nov 2007 12:30:18 -0600, Maps-L <[log in to unmask]> wrote:
>
>>>
>>> KML is quickly becoming a primary standard for distribution of
>>> geographic
>>> content on the internet.
>>
>> May be for mashers. But hardly any professional in the GI and remote
>> sensing industry uses KML for this purpose. It is simply not suitable,
>> it
>> has no data attribute or metadata carrying capabiities.
>
> This is incorrect. KML does in fact provide mechanisms for carrying
> additional data attributes, and is adding support for metadata.
>
> http://code.google.com/apis/kml/documentation/extendeddata.html

Oh pleeeze! This is a very low-level stuff. You are surely not seriously
suggesting using KML as a substitute for shape files, netCDF or DBMS
formats to distribute geoigraphic information. It is so inefficient and
unwieldy.


>
>>
>> Google has even submitted KML to the Open
>>> Geospatial Consortium.  Google Earth is simply a KML viewer and is
>>> certainly
>>> not the only program capable of displaying KML files.  NASA's World
>>> Wind
>>> (public domain) is just one example of another program that can view
>>> KML
>>> (although limited right now).  Even Microsoft Virtual Earth is starting
>>> to
>>> add KML viewing to its list of features.  In the next few years, we
>>> will
>>> see
>>> many other 3rd party applications (web browser plugins, etc.) that can
>>> view
>>> KML.  Also, don't forget that Google generates advertising revenue
>>> simply by
>>> listing a link to a website in its database.
>>
>> Exactly. Google Earth is gee-whiz but otherwise rather limited piece of
>> technology that is a means to attract people to a place where Google
>> displays advertising. Google Earth is a like a museum (perhaps art
>> gallery
>> is a better anology) where you can go and look, but you cannot do much
>> more than look. The general public like it for this reason, but for most
>> in the GI industry this is not what is wanted. They want to be able to
>> query, manipulate, take out of context, and combine with other
>> information, the information displayed on GE.
>
> This is true of GoogleEarth which is primarily a viewer, and lightweight
> content creation tools. But more tools are adding support for creating
> and
> manipulating KML. And part of the OGC effort of standardization is adding
> KML output to WMS. Other sites, like my own Mapufacture, also are
> building a
> large, open database of data sources and simple querying capabilities.
> GeoServer, and I believe ArcIMS 9.3, are two other widely used pieces of
> software adding KML support.

Manifold System 8.x can too, but that does not make KML a suitable format
for distributing geographic information types other than for those who
want to build mash-ups with GE or similar.

Read:

http://www.manifold.net/doc/export_drawing_kml_kmz.htm

You will note that KML only supports geopositioning wrt latitude-longitude
using WGS84.


>>> Another advantage of KML is that data created and hosted by many
>>> different
>>> institutions can all be integrated together seemlessly.  Try doing that
>>> with
>>> all the proprietary web-browser plugins that most map libraries are now
>>> using.
>>
>> Map libraries should be providing their scanned maps in standard image
>> file formats.
>
> And using KML as a mechanism for syndicating the location (geographic and
> URLs) is simple to do and effective.

No what it is, is unecessary. The location information should be invisibly
embedded in the data files.

----------------------------------------------------------------------
Nicholas J. Verge BSc. FGS
Henley-on-Thames, Oxfordshire, UK