Create a canopy height model (CHM) by subtracting DSMs¶

Create canopy height model (CHM) from bare soil and plant height digital elevation model (DEM) or digital surface model (DSM) images. Calculates the soil elevation as a subtraction of the DSM with plant height from the DSM with bare soil. Note: the input DSMs need to be the same shape.

plantcv.geospatial.subtract_dsm(dsm1, dsm0)

returns DSM image object object where the array is the subtracted CHM.

• Parameters:

  • dsm1 - DSM image object from a timepoint with plants, likely read in with geo.read_geotif
  • dsm0 - DSM image object from a bare ground timepoint, likely read in with geo.read_geotif

• Context:

  • This function will output a DSM image object that can then be used by analyze.chm to analyze plant height within a given area.

import plantcv.geospatial as gcv
import plantcv.plantcv as pcv

# Read in dsm as geotif
dsm1 = gcv.read_geotif(filename="./data/example_dsm.tif", bands=[0])
dsm0 = gcv.read_geotif(filename="./data/example_dsm.tif", bands=[0])

# To get the canopy height model:
pcv.params.debug = "plot"

chm = gcv.subtract_dsm(dsm1, dsm0)

Source Code: Here