MapInfo Spatial Server Map Tiling Service - Product Documentation ...

There is one restriction when defining a map: the resultant tile height must be a whole number (integer).
Since tile height and tile width are calculated in pixels, it is impossible for a user to display these values
as fractions of a pixel.
For example, a map with a bounds of (-180, -90, 180, 90) in WGS84 has an aspect ratio (width to height)
of 2:1. So the tileHeight calculation is half the tileWidth. If you defined the tileWidth parameter
to be 256 then the tileHeight would be 128. This is an acceptable tileHeight value. However, if
you have defined a map with the bounds of (-180, -90, 90, 0) in WGS84, that would create an aspect
ratio of 3:1. Calculating the tileHeight based on a tileWidth of 256 would result in a tileHeight
of 85.3333333. This is not an acceptable tileHeight value, and will not be displayed by the Map Tiling
Service. If a map hosted by the Map Tiling Service is configured with tileWidth and bounds parameter
settings that result in an invalid tileHeight calculation, then the map will not appear in the list of
available maps returned by a call to the getMaps method in the Map Tiling Interface.
Map Tiling Service Guide
Chapter 2: Managing Map Tiling Resources and Configuration
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