is it possible to creat a web application with openStreetMap?
with a specified map, and private layers available only for registered users?
and also, is it possible to create a layer, where the colors of, say, buildings in a layer changes according to specifications we define? each color implies something of course
welcome to the forum!
Yes, of course, it is possible to create your own map. OpenStreetMap is just a huge database containing geographical data and lots of relations between them. The creation of a map image is called “rendering”, and it’s up to you how you do it and which parameters you use.
For a web service you could use Mapnik (this program is used for the osm.org default map layer too) and change the rendering parameters (style file “osm.xml”) as you like. Some maps use overlays, e.g. “openptmap.de”. Just click on the “+” in the upper right corner and choose the map/overlay combination.
This is not quite correct. Data is currently published under the terms of CC-BY-SA 2.0 only. It is planned that data will be published, under the terms of ODbL in the future, but no OSM data has been made available under that license so far.
Yeah, even the ODBL/CT if you want to be more accurate. But important is that mixing osm data and own data in your application is allowed only with certain conditions (especially the “share-alike” which means " If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.").
So before you discuss the possible technical implementations, check first on the legal-talk if your project is compatible with the license.