Zabbix api value is different from Graph value

Question

i have zabbix 5. I've been trying to write a shell script to get item trend for a range of time. the shell script works correctly but the value it return doesn't match what is showing on graph.
for example:

I have an item with itemid "10234" which return "percentage of used CPU".
i want to get the zabbix trend for this item from "2021/09/20 09:00:00" till "2021/09/21 09:00:00".
Unix time for this rang is: 1632112200, 1632198600

I run this command to get the values:
curl -L -k -i -X POST -H 'Content-Type:application/json' -d '{"jsonrpc":"2.0","method":"trend.get","id":1,"aut h":"1a543455bd48e6ddc222219acccb52e9","params": {"output": ["clock","value_avg","value_min","value_max","num", "itemid"],"itemids":["10234"],"time_from": "1632112200","time_till": "1632198600", "limit": "1"}}' https://172.30.134.03:423//api_jsonrpc.php

output:
{"clock":"1632114000","value_avg":"14.968717529411 764","value_min":"12.683622999999997","value_max": "17.635707999999994"}

but in Graph it shows:

why this happens and how to fix it?

Answer 1

In most cases, the graphs apply approximations. If you zoom in, you should see the same data you get from the API. The most zoom you can apply is 1 minute, while the API will get you the exact point in time value.