public float getLookupValue(int key) {
        float res = 0f;
        final int val = lookupData[key];
        if (val == 0) {
            return Float.NaN;
        }
        res = (val - 1000) / 100f;
        return res;
    }
decode a byte-array into a lookup data array
main/src/main/java/cgeo/geocaching/brouter/expressions/BExpressionContext.java