SETUP: Write paragraph about seeding the map.

SETUP.md

@@ -40,8 +40,8 @@ Use `mtdbconverter --help` to see all options.
 
 ## Start mtredisalize
 
-`mtredisalize` is the component which serves the block data to Minetest and the `mtwebmapper` as a Redis
-server look-alike. Start it with:
+`mtredisalize` is the component which serves the block data to Minetest and `mtwebmapper` as a Redis
+look-alike server. Start it with:
 
     mtredisalize                               \
       -host=localhost                          \
@@ -57,14 +57,37 @@ The `-change-url=` option is a forward reference to the `mtwebmapper` server whi
 world has changed. If it is not configured the tile re-generation is not triggered. As long as the Minetest server
 is down there will be no changes and therefore it is safe to configure it even if the `mtwebmapper` service is not
 running.  
-The `-change-duration=` option specifies the amount o time ho long the `mtredisalize` server aggregates changes
-made to the world before reporting them to `mtwebmapper`. It defaults to 30 seconds but the value can
+The `-change-duration=` option specifies the amount of time how long the `mtredisalize` server should aggregate
+changes made to the world before reporting them to `mtwebmapper`. It defaults to 30 seconds but the value can
 be increased or decreased depending how often you want to update the map. Decreasing it will increase the
 computing pressure on your system so configure it wisely.
 
 
 ## Pre-compute the map tiles with mtseeder
-**TODO: Write me!**
+
+Even in a dynamical Mintest world played with many players most of the data is static over time. To generate
+a basic map to apply only changes to use `mtseeder`:
+
+    GOMAXPROCS=6 mtseeder              \
+      -colors=/path/to/your/colors.txt \
+      -output-dir=/path/to/your/map    \
+      -workers=3
+
+This contacts the `mtredisalize` server running at localhost port 6379 to fetch the block data from. You will
+need a `colors.txt` to map the block nodes to pixel colors of your map. The repository contains
+[one](https://bitbucket.org/s_l_teichmann/mtsatellite/raw/default/colors.txt). See `mtseeder --help` for
+all options.
+
+The `-workers=` option and the `GOMAXPROCS=` environment variable are completely optional but very useful
+to exploit multiple processor cores on your machine. Set `GOMAXPROCS=` to the result of `nproc` and `-workers=`
+to a number a little lesser. You have to experiment with this to find a good setting.
+
+Even with good CPU usage generating the map and overview image tiles take a while.
+
+Tip: A lot of the Minetest map tiles are white/empty but are saved as dupes in the file system. To
+deduplicate them you can use e.g. [hardlink](https://bitbucket.org/s_l_teichmann/hardlink). You
+can also run it as a nightly cron job to dedupe the map on a regular basis.
+
 
 ## Start the web server mtwebmapper
 **TODO: Write me!**