Sandwich error on adjacent bbox

[support4net]

Hi, I have found a problem in composing a set of tiles formed by adjacent sandwiches. The result is a gray area full of tiles rendered at full extent size.

Here are the details:

• South of Europe is a sandwich defined by several sources calling the mapnik styles for specific zoom levels that have a common definition: "bounds": { "west": 3.8, "south": 34.4, "east": 16.15, "north": 46.5, "low": 9, "high": 14 },
• Africa is a sandwich in the same way define with the common definition: "bounds": { "west": -31.5, "south": -85, "east": 65, "north": 34.4, "low": 15, "high": 20 },
• Each one can work independently and is correctly rendered but when combined both in a superior class sandwich will crash.

example:

 "tms":
    {
        "provider":
        {
            "name": "Sandwich",
            "stack":
            [
                    {"src": "baselow", "zoom": "1-5"},
                    {"src": "base", "zoom": "6-19"},
                    {"src": "euS", "zoom": "6-19"},
                    {"src": "AFR", "zoom": "6-19"},
                    {"src": "countries", "zoom": "6-19"},
                    {"src": "cities", "zoom": "6-19"}
            ]
        }
    },

[rburhum]

Is it a proper 'crash' with a call stack or an incorrectly rendered result (i.e. the gray area you mention)?