I found that 1ML displays almost double the number of nodes comparing to other lightning network explorers.
I think 1ML does not provide the datasource but are you able to guess about the reason of the difference?
Besides 1ML, the numbers of nodes are almost same.
My own c-lightning nodes shows about 4,000 by listnodes command and lightning.chaintools.io uses lnd's GetNetworkInfo rpc call according to their source code.
Nodes: 7,462 Channels: 39,310
Nodes: 4,011 Channels: 39,514
- Indexplorer https://graph.lndexplorer.com/
Nodes: 3,941 Channels: 38,983
- Lightning Explorer https://lightning.chaintools.io/
Nodes: 3,971 Channels: 39,201
- Lightning Explorer https://explore.casa/
Nodes: 3,978 Channels: 39,009