In a windowless control room on an army base in southern Israel, five soldiers monitored the displacement of hundreds of thousands of Gazans on a massive computer screen.

The screen showed a live map of northern Gaza, the densely populated area of roughly 1.1 million residents who were told on Friday by the Israeli military to head south for their own safety. Using data harvested mainly from more than one million mobile phones, the map gave the soldiers a real-time assessment of how many Gazans had heeded Israel’s demand.

The Israel Defense Force has telegraphed for days that it will soon begin a ground operation in northern Gaza to oust Hamas, the armed Palestinian group that controls Gaza and orchestrated the worst terrorist attacks in Israel’s history on Oct. 7, killing more than 1,400 people and abducting at least 199 others. Israeli counterattacks have killed more than 2,800 Palestinians, according to the Gazan health authorities.

The Israeli military allowed a New York Times journalist to view the data-tracking system, hoping to show that it was doing what it could to reduce harm to civilians — even as its warplanes killed hundreds more Palestinians on Monday, including in southern Gaza, where civilians had been told to take shelter.

Some neighborhoods were colored white and red on the screen, suggesting that they still housed the majority of their residents. But an increasing number of areas were turning green and yellow, signaling that most of their residents had left.

“It’s not a 100 percent perfect system — but it gives you the information you need to make a decision,” said Brig. Gen. Udi Ben Muha, who oversees the monitoring process. “The colors say what you can and can’t do,” General Ben Muha said.

With political leaders yet to give the final go-ahead for a ground operation, the Israeli military was locked in a holding pattern on Monday. On Monday night, its troops remained massed on the border of Gaza, yet to advance across it. The army was watching to see how many civilians had left northern Gaza.

It was also giving last-minute training and equipment to the hundreds of thousands of military reservists who had been called up for the war effort. And the extra few days have given diplomats time to conduct last-minute — and, so far, unsuccessful — negotiations about opening Gaza’s border with Egypt to evacuees and aid convoys.

Benjamin Netanyahu, the Israeli prime minister, has also invited President Biden to visit Israel this week, and the military was unlikely to complicate his visit by starting an invasion while he was on Israeli soil, analysts said.

“The ground operation is going to have lots of casualties on both sides,” said Miri Eisin, a former senior military officer and the director of the International Institute for Counter-Terrorism at Reichman University in Israel.

“You don’t want to do that when the U.S. president is here,” she added.

In the meantime, three senior Israeli commanders said they were using every moment to prepare the reservists for ground warfare. The expected operation will be the first in nearly 15 years in which Israel will attempt to capture and hold onto land for a prolonged period. Many full-time soldiers have never conducted such an operation, let alone the 360,000 reservists called up from their day jobs since the Hamas attacks.

A significant minority of infantrymen and tank units likely to be deployed in Gaza are reservists, according to three senior officers, who were not authorized to speak publicly. The Israel Defense Forces were believed to have 200,000 active-duty troops before the call-up, of whom three-quarters were conscripts, but there are no official figures.

It has taken the military time to stock up on enough equipment for its army. While Israel’s commandos all have enough protective gear, the army is still securing protective vests for some reservists, according to one senior officer. Several families have also said they privately obtained vests for sons who were called up.

In the meantime, more Palestinian civilians are leaving northern Gaza, albeit to dire conditions in the south, where there is a lack of accommodation, fuel, water, medicine and food — and where Israeli strikes also continue.

Many Palestinians say they fear that Israel ultimately seeks to force them into Egypt, never to return, in a mass expulsion that they compare to the Nakba, an Arabic term that refers to the flight or expulsion of 700,000 Palestinian Arabs during the wars that surrounded the creation of Israel in 1948.

Israel says the call to evacuate is to prevent as many civilian casualties as possible during upcoming military operations in the north.

To that end, from the military control room in southern Israel, General Ben Muha was trying to encourage more Gazans to head south. Military officers called Palestinians directly, and Air Force planes dropped leaflets that urged Gazans to ignore Hamas’s demands for them to stay put.

Spread across the general’s desk were dossiers and spreadsheets that listed the phone numbers of hundreds of Gazan community leaders, hospital directors and school administrators — all of whom could be phoned at a moment’s notice by a soldier in the control room.

On a whiteboard nearby, aides had detailed the timing of the regular airdrops of leaflets across northern Gaza.

On the live map in front of the general, there were fewer and fewer patches of red and white: Up to 700,000 Gazans had moved south by Monday afternoon, the data suggested, leaving about 400,000 in the north.

Once a neighborhood turns green on the map, an Israeli officer operating in the area will have greater room for maneuver because of the reduced likelihood of harming civilians during the fight against Hamas, the general said.

“If you are a brigade commander and you see those colors, it tells you how many civilians are in the area, and you know if you can or can’t use your tank, your infantry,” he said.

Palestinians say that such measures mean little amid the steep loss of life and hardship caused by the bombings and the displacement. Civilians and aid workers say that many people lack transportation to move southward, or are too infirm to make the trip.

“I don’t think there’s anything humanitarian about uprooting” so many people, said Khaled Elgindy, director of the Program on Palestine and Palestinian-Israeli Affairs at the Middle East Institute, a research group in Washington.

“There is no place in Gaza that is safe,” Mr. Elgindy added by phone on Monday. “So the whole notion that they are somehow behaving in a way that is humanitarian or respects human life in Gaza is Orwellian.”

The monitoring method has already been used during Israeli Air Force strikes on Rimal, a wealthy neighborhood in Gaza City that was left in ruins after being bombed last Tuesday in retaliation for the Hamas attacks. Israeli officials said that Hamas had built military infrastructure underneath the neighborhood.

Ahead of that attack, soldiers in the monitoring room called some residents in the area to encourage them to leave, the general said. They then notified the Air Force as soon as the neighborhood turned green on the map, indicating that less than a quarter of its population remained, the general said.

The general said that, before proceeding, the Air Force had conducted its own assessment of the potential cost to civilian lives from each individual strike.

But such checks only went so far.

Among the civilians killed during the strikes was Saeed al-Taweel, the editor of an Arabic news website.

Patrick Kingsley reported from Beersheba, Israel, and Ronen Bergman from Kfar Azza, Israel. Johnatan Reiss contributed reporting from Caesarea, Israel.