QGIS Color Map

This notebook allows you to create a color map readable by QGIS.

You must first create a Excel file with your RGB code.

This is an example for the Scene Classification map (see Sentinel-2 preprocessing).

SCL Color Map

[4]:

import pandas as pd
import os

print('Pandas library successfully imported!')

Pandas library successfully imported!

Set directory

[8]:

computer_path = '/export/miro/ndeffense/LBRAT2104/'
grp_nb        = '99'

work_path = f'{computer_path}STUDENTS/GROUP_{grp_nb}/TP/'

cmap_path = f'{work_path}COLOR_MAP/'

print(f'The folder where your color map is located is : \n {cmap_path}')

The folder where your color map is located is :
 /export/miro/ndeffense/LBRAT2104/STUDENTS/GROUP_99/TP/COLOR_MAP/

Set parameters

[9]:

col_with_name = 'scl'
col_with_code = f'{col_with_name}_nb'

# Input file (.xlsx or .xlsm)
cmap_xls = f'{cmap_path}cmap_{col_with_name}.xlsm'

# Output file (.clr)
cmap_clr = f'{cmap_path}cmap_{col_with_name}.clr'

Check if Excel table color map exists

[11]:

if not os.path.isfile(cmap_xls):
    print(f'Check if the excel file exists and is stored in the right foled \n {cmap_path}')
else:
    print(f'OK excel file exists : \n {cmap_xls}')

OK excel file exists :
 /export/miro/ndeffense/LBRAT2104/STUDENTS/GROUP_99/TP/COLOR_MAP/cmap_scl.xlsm

Read Excel color map

[12]:

df = pd.read_excel(cmap_xls, usecols=[col_with_name,'R','G','B','T',col_with_code])

df.dropna(how='all', inplace=True)

df = df.astype({'R': 'int32', 'G': 'int32', 'B': 'int32', 'T': 'int32', col_with_code : 'int32'})

df

[12]:
scl_nb R G B T scl
0 1 0 0 0 255 No Data (missing data)
1 2 59 0 0 255 Saturated or defective pixel
2 3 47 47 47 255 Dark features / Shadows
3 4 100 50 0 255 Cloud shadows
4 5 0 161 0 255 Vegetation
5 6 255 231 90 255 Not-vegetated
6 7 0 0 255 255 Water
7 8 129 129 129 255 Unclassified
8 9 193 193 193 255 Cloud medium probability
9 10 255 255 255 255 Cloud high probability
10 11 100 201 255 255 Thin cirrus
11 12 255 151 255 255 Snow or ice

Write color map in QGIS style

[13]:

f = open(cmap_clr, "w")
f.write(df.to_string(index=False, header=False))
f.close()

Congratulations !

Now, you can open your GeoTIFF in QGIS and load the color map file (.clr)

Load Color Map