String jvxlReadData(String type, int nPoints) {
		String str = "";
		try {
			while (str.length() < nPoints) {
				line = br.readLine();
				str += jvxlUncompressString(line);
			}
		}
		catch (Exception e) {
			Logger.error("Error reading " + type + " data " + e);
			throw new NullPointerException();
		}
		return str;
	}