... I have one point of criticism. We Dutchmen in the Netherlands don´t live underwater. The fact that half of our country is below sealevel does not mean we need divers equipment to live in our houses, nor that we have underwater trains.
Thank you for this critical observation.
It will always be a problem with such low lands, like a river delta. There is no fault in the data, just our interpretation of the data. We may think to shift upwards the elevation a little, but problems will appear in other places along coastlines.
In spite of this, there is a way to recover dry land below sea level. I will summarize the steps below to see if it worth the effort.
In this figure the land below sea level is coloured in blue. We also have the coastlines superimposed over the map. Theoretically, anything inside coastlines is dry land or some sort of rivers/lakes. Indeed, the Netherlands is placed in such a location.
Topographic data, like SRTM 90m
, contain data only inside these coastlines. Over open oceans they have no data. This can be used to create a land mask map
, for example using GETOPO30 data.
At this stage we require an image editor to combine the land mask map with the map produced from bathymetric data. The final result is shown here as a Simutrans map.
Using this technique I create a new version of Europe map below. Please compare it with the original one. Comments are welcomed.http://simutrans-germany.com/files/upload/europe2.zip