Add ee.Feature or ee.FeatureCollection using cartoee

[ErikSeras]

Hi, I have a question,

Is it possible to add ee.Feature or ee.FeatureCollection usinggeemap.cartoee.add_layer()?

Thanks for your support.

[giswqs]

cartoee.add_layer() only supports ee.Image. You can convert ee.FeatureCollection to ee.Image by using image.paint() or featureColleciton.style()

[GokulGeo]

Enhanced features like a scale bar and north arrow can easily lift the use of a gis software and do everything in geemap.

[giswqs]

There's an existing library for adding a scalebar to matplotlib that might be of help: https://github.com/ppinard/matplotlib-scalebar

Also see SciTools/cartopy#490

[GokulGeo]

I tried and got output but the scale bar is having some issue with geospatial data so I had opened an issue in the repository ppinard/matplotlib-scalebar#34

[ErikSeras]

I tried this way to add a scale bar

import ee
import geemap
from geemap import cartoee
import cartopy.crs as ccrs
%pylab inline

try:
    ee.Initialize()
except Exception as e:
    ee.Authenticate()
    ee.Initialize()

# https://stackoverflow.com/a/50674451/2676166
def scale_bar(ax, length=None, location=(0.5, 0.05), linewidth=3, color = "black"):
    """
    ax is the axes to draw the scalebar on.
    length is the length of the scalebar in km.
    location is center of the scalebar in axis coordinates.
    (ie. 0.5 is the middle of the plot)
    linewidth is the thickness of the scalebar.
    """
    #Get the limits of the axis in lat long
    llx0, llx1, lly0, lly1 = ax.get_extent(ccrs.PlateCarree())
    #Make tmc horizontally centred on the middle of the map,
    #vertically at scale bar location
    sbllx = (llx1 + llx0) / 2
    sblly = lly0 + (lly1 - lly0) * location[1]
    tmc = ccrs.TransverseMercator(sbllx, sblly)
    #Get the extent of the plotted area in coordinates in metres
    x0, x1, y0, y1 = ax.get_extent(tmc)
    #Turn the specified scalebar location into coordinates in metres
    sbx = x0 + (x1 - x0) * location[0]
    sby = y0 + (y1 - y0) * location[1]

    #Calculate a scale bar length if none has been given
    #(Theres probably a more pythonic way of rounding the number but this works)
    if not length: 
        length = (x1 - x0) / 5000 #in km
        ndim = int(np.floor(np.log10(length))) #number of digits in number
        length = round(length, -ndim) #round to 1sf
        #Returns numbers starting with the list
        def scale_number(x):
            if str(x)[0] in ['1', '2', '5']: return int(x)        
            else: return scale_number(x - 10 ** ndim)
        length = scale_number(length) 

    #Generate the x coordinate for the ends of the scalebar
    bar_xs = [sbx - length * 500, sbx + length * 500]
    #Plot the scalebar
    ax.plot(bar_xs, [sby, sby], transform=tmc, color= color, linewidth=linewidth)
    #Plot the scalebar label
    ax.text(sbx, sby, str(length) + ' km', transform=tmc,
            horizontalalignment='center', verticalalignment='bottom', color = color)


point = ee.Geometry.Point(123.488, -8.284)

volcano = ee.ImageCollection("COPERNICUS/S2_SR").filterBounds(point).filterDate("2020-11-28", "2020-12-04").first()


# Cambiar el tamaño de la figura
plt.figure(figsize=(16, 12))

region = [123.3,-8.5,123.8,-8.18]
vis = {'min':0,'max':6000, 'bands':'B4,B3,B2'}

ax = cee.get_map(volcano, region=region, vis_params=vis)
cee.add_gridlines(ax,interval=(0.1,0.1),linestyle=":")

ax.set_title(
    label = 'Lewato volcano 2020-11-29',
    fontsize = 15
)

scale_bar(ax, 5, location=(0.1, 0.05), linewidth= 1.5, color = "white")


plt.show()

[giswqs]

Looks good. Would you like to submit a pull request so that you can get credit for this? It seems we can also add a north arrow.

# source: https://bit.ly/3mhaU2q
import geopandas as gpd
import matplotlib.pyplot as plt

gdf = gpd.read_file(gpd.datasets.get_path('nybb'))

fig, ax = plt.subplots(figsize=(6, 6))
gdf.plot(ax=ax)

x, y, arrow_length = 0.1, 0.9, 0.2
ax.annotate('N', xy=(x, y), xytext=(x, y-arrow_length),
            arrowprops=dict(facecolor='black', width=5, headwidth=15),
            ha='center', va='center', fontsize=20,
            xycoords=ax.transAxes)

[giswqs]

Here is a version with both scalebar and north arrow

import ee
import geemap
from geemap import cartoee as cee
import cartopy.crs as ccrs
# %pylab inline

geemap.ee_initialize()

# https://stackoverflow.com/a/50674451/2676166
def scale_bar(ax, length=None, location=(0.5, 0.05), linewidth=3, color = "black"):
    """
    ax is the axes to draw the scalebar on.
    length is the length of the scalebar in km.
    location is center of the scalebar in axis coordinates.
    (ie. 0.5 is the middle of the plot)
    linewidth is the thickness of the scalebar.
    """
    #Get the limits of the axis in lat long
    llx0, llx1, lly0, lly1 = ax.get_extent(ccrs.PlateCarree())
    #Make tmc horizontally centred on the middle of the map,
    #vertically at scale bar location
    sbllx = (llx1 + llx0) / 2
    sblly = lly0 + (lly1 - lly0) * location[1]
    tmc = ccrs.TransverseMercator(sbllx, sblly)
    #Get the extent of the plotted area in coordinates in metres
    x0, x1, y0, y1 = ax.get_extent(tmc)
    #Turn the specified scalebar location into coordinates in metres
    sbx = x0 + (x1 - x0) * location[0]
    sby = y0 + (y1 - y0) * location[1]

    #Calculate a scale bar length if none has been given
    #(Theres probably a more pythonic way of rounding the number but this works)
    if not length: 
        length = (x1 - x0) / 5000 #in km
        ndim = int(np.floor(np.log10(length))) #number of digits in number
        length = round(length, -ndim) #round to 1sf
        #Returns numbers starting with the list
        def scale_number(x):
            if str(x)[0] in ['1', '2', '5']: return int(x)        
            else: return scale_number(x - 10 ** ndim)
        length = scale_number(length) 

    #Generate the x coordinate for the ends of the scalebar
    bar_xs = [sbx - length * 500, sbx + length * 500]
    #Plot the scalebar
    ax.plot(bar_xs, [sby, sby], transform=tmc, color= color, linewidth=linewidth)
    #Plot the scalebar label
    ax.text(sbx, sby, str(length) + ' km', transform=tmc,
            horizontalalignment='center', verticalalignment='bottom', color = color)


point = ee.Geometry.Point(123.488, -8.284)

volcano = ee.ImageCollection("COPERNICUS/S2_SR").filterBounds(point).filterDate("2020-11-28", "2020-12-04").first()


# Cambiar el tamaño de la figura
plt.figure(figsize=(16, 12))

region = [123.3,-8.5,123.8,-8.18]
vis = {'min':0,'max':6000, 'bands':'B4,B3,B2'}

ax = cee.get_map(volcano, region=region, vis_params=vis)
cee.add_gridlines(ax,interval=(0.1,0.1),linestyle=":")

ax.set_title(
    label = 'Lewato volcano 2020-11-29',
    fontsize = 15
)

scale_bar(ax, 5, location=(0.9, 0.05), linewidth= 1.5, color = "red")

x, y, arrow_length = 0.9, 0.2, 0.1
ax.annotate('N', xy=(x, y), xytext=(x, y-arrow_length), color="white",
            arrowprops=dict(facecolor='white', width=5, headwidth=15),
            ha='center', va='center', fontsize=20,
            xycoords=ax.transAxes)

plt.show()

[giswqs]

Thanks to the stackoverflow sample code. I have added two more functions to cartoee, add_scale_bar() and add_north_arrow(). See notebook example - cartoee_scalebar.ipynb