Quickly delivering aid after a disaster is an aid agency's job, yet sometimes in the confusion people get overlooked and lives are lost.
Now a New Zealand engineering firm has come up with a way to identify those in danger -- they call it "rapid mapping".
When Cylcone Winston caused chaos in Fiji, communications were down and some people were forgotten.
Newshub discovered one devastated island that hadn't been visited after three days.
"I was very surprised to hear that we were the first to land. They hadn't been able to tell anyone that they had been injured," says Newshub reporter Melissa Davies.
It's not easy for governments and aid agencies to know where to go.
But engineers from a New Zealand company have designed a way to help.
"The idea is that within 24 hours to get the first version of the map out, and then 48 hours a better version, and 72 hours another version," says John Leeves from Tonkin and Taylor.
When Winston hit, engineer Peter Quilter caught the first plane to Fiji and got hold of 700 high-resolution aerial photos taken by the New Zealand Defence Force.
Combining the photos' GPS data with information about the cyclone's path, wind patterns, roads and ports, the team provided a roadmap for disaster relief.
"The aid agencies are thrilled because they were able to look at the map, look at the photos and really understand what is going on in the areas that they are sending their staff to," says Mr Leeves.
"We had lots of local partners on the ground, but they couldn't get the information to us, so when we had those over-flights and had those images, that was a key piece in putting together that early assessment," says Darren Brunk from Disaster Relief Forum.
It was the Christchurch earthquakes that sparked the engineering company to develop rapid mapping, plus a sense of "what can we do to help?"
"We've learnt how we can help we think, so we were dead keen to do that," says Mr Leeves.
It's a simple idea of coordinating information, which may provide a lifeline in the wake of a disaster.