Layered Rasters with custom colors

[markobud]

Hi!
I'm trying to overlay different rasters, each with a different color scale, but I'm unable to make it work (below my current approach). Do you have any advice on how to move forward?

Thanks,
Marko

import os
import leafmap.leafmap as leafmap

landsat = 'landsat.tif'

url1 = "https://open.gishub.org/data/raster/landsat7.tif"
satellite = leafmap.download_file(url1, "landsat.tif")

m = leafmap.Map()

for b,name,cmap_name in zip([2,1,3],['red','green','blue'],['Reds','Greens','Blues']):
    m.add_raster(landsat, bands=b, layer_name=f'Landsat_{name}',cmap = cmap_name)

m

[giswqs]

Thank you for reporting. This bug has been fixed in #674. You can update the package using leafmap.update_package() after the PR is merged.

[banesullivan]

Ah yes, this is the one thing that I was unable to handle in localtileserver's transition from large-image to rio-tiler. Its possible to do this, I just need to account for in localtileserver.

Sorry for the loss of functionality! I didn't think many people were using custom colormaps like this

[rbuehler]

Hello, I am running into this same issue too.
(how to use custom colormaps with localtileserver/rasters in leafmap)
Is there any news on this?
Thank you very much

[giswqs]

See https://leafmap.org/notebooks/103_raster_colormap/

[rbuehler]

I had seen this solution, but plotting an image is not the same e.g. for changing to other color maps after, or reading out pixel values. I guess workarounds can be done here too, but it would be much cleaner if one could define custom color maps for the raster.
Btw, I would have expected that registering the color map with rio-tiler works, but it didn't for me.
As there is workarounds I understand it is not high priority, but if there is any change on this I would appreciate a note here. Thanks again.

[giswqs]

Try this:

import matplotlib
import leafmap

colormap = matplotlib.colors.LinearSegmentedColormap.from_list(
    'ndvi', [
        '#422112',
        '#724C01',
        '#CEA712',
        '#FFA904',
        '#FDFE00',
        '#E6EC06',
        '#BACF00',
        '#8BB001',
        '#72A002',
        '#5B8D03',
        '#448102',
        '#2C7001',
        '#176100',
    ],
    256,
)
m = leafmap.Map()
url = "https://github.com/giswqs/data/raw/main/raster/landsat7.tif"
m.add_raster(url, indexes=[1], colormap=colormap)
m

[markobud]

Thanks both for your time! @giswqs and @banesullivan!