elevation differences between DTMs

[StanislavaV]

Hello friends,

i have two DTMs and two DSMs created from LAS files......

first LAS files were created in autumn

second LAS were created in spring

when i compare elevations between DTM autumn and DTM spring.......differences are minimal, but to and fro are big differences, like -50 metres

same at DSMs..

what could have caused it? may it be caused by noise by scanning or even something else?

thank you so much

[DanPatterson_Retired]

So it is 0.5 meters... well that is a whole lot different that 50 meters.

A lot can happen to give rise to a 50 cm = 0.5 m difference in elevation between the fall and winter in an area.

A pile of dirt, a dug hole, error, the list goes on

You will have to elaborate on the area a bit more and perhaps show a map of the elevations and their differences

[SteveLynch]

I understand the problem to be as follows. We have two rasters each with a cell size of 0.5 meters and when subtracting them from each other we see differences of 50 meters.

[StanislavaV]

Yes it agrees. These big deviations are only 1% of whole raster.

[JodieParkes1]

Hello - I was wondering what process you took to compare two DTMs?

Cheers,

Jodie

[StanislavaV]

hi Jodie,

i used Minus.