The lines and bars on the charts accompanying this story may seem vivid and crisp enough on the printed page, but they point to a bleak -- and still somewhat fuzzy -- picture of the nation's 1979-80 economic outlook.

Although the forecasters' track record has been spotty in recent years, this time the prognosticators are peetty well agreed: Inflation will continue at an uncomfortable pace, and the economy will slide into a mild recession.

The dispute is over how long and deep the downturn will be, and how much if any, inflation actually will slow. But even here, the disagreements are relatively minor.

The fuzziness at the edges stems from the large number of uncertainties that surround the outlook now: A continued sharp rise in interest rates, anouther round of big oil-price increases -- all could alter the situation.

At the optimistic end of the spectrum is the Carter administration, which officially predicts only a mild slump this year and next, with joblessness rising to 7 percent or so in 1980 and inflation slowing to 8.3.

But the administration itself has some doubting Thomases: A subcabinet task force recent predicted the slump would be worse than expected, with joblessness rising to 8.2 percent in 1980 and inflation holding at 9 percent or higher.

Ironically, the consensus of private forecasters runs almost precisely between those two parameters. The differences depend upon the forecaster's views of the likely impact of interest rates and inventory buildups.

After reaching a peak of just below 9 percent in 1975, the jobless rate fell to 6 percent or lower in 1978 and has remained since then in the 5.8 percent range -- effectively all "full employment."

The jobless rate just began edging up last month, when unemployment rose three-tenths of a percentage-point to 6 percent of the work force. Most analysts are certain it will accelerate in months to come.

But the big shock has come in the inflation rate. After slowing to a 4.8 percent rise in 1976, consumer prices leaped by 6.8 percent in 1977 and soared 9 percent in 1978 -- far beyond almost everyone's expectations.

This year, inflation has been running so far at a 13 percent annual rate. Although that's expected to slow somewhat this autumn, the relief will be only temporary. Prices are likely to speed up again in 1980, economists say.