-------- 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