Create tiles without OSM-Data from very beginning

Hi community,

for a private project I am going to create an indoor map of a single floor of a building to display it’s rooms and unique seats. The map is going to be displayed on a website, especially for this one map. I don’t need any existing data available at or similar, I really just want to “draw” the floors outline and do some indoor mapping without ANY additional data.

I firstly googled some time but am confused. Things I read and watched videos about are Leaflet, QGIS and Tilemill. I used JOSM before for private purposes to tag some things in my free time. Do I need josm at any point?
On the one hand QGIS seems to be used for the drawing of the outline and Tilemill is for designing the raw data created with QGIS.
On the other hand I saw maps created with QGIS that looked fully designed.

It’s clear, that Leaflet’s task is to display the map itself on the hosted website. But QGIS and Tilemill confuse me. What tool (another than one of those) do I need to draw the outline of the floor and the rooms.

Or from beginning to the end:

What tool do I need in which order to achive my goal?

Best regards

Edit: Typo

JOSM’s certainly an option, if you want to create some data in the same format as OSM data tends to be in and want to display it using tools designed to display OSM data.

That’s how I started to create the map legend that you can see at . The roads that you see there are actually i OSM files in , and the scripts in there append it to a “normal” OSM rendering database. For completeness the map itself (using Leaflet) is at .

However, this assumes that you need to use OSM tools (which are designed to work with far more data than you want to here). If you just want to show a map of the floor of a building then you might not even need a data driven “slippy map” (either vector or raster tile based). I’d expect that “just drawing a picture” with your favourite drawing tool might be quicker. Another option (which does assume OSM-format data) might be Maperitive: .