NASA GIBS Colormaps for Python

nasa_gibs_colormaps.py

def xmlcmap2cmap(xmlcmap):
    import numpy as np
    import matplotlib.colors as mc
    inf = np.inf
    nan = np.nan
    for elem in xmlcmap:
        if elem.tag == 'Entries':
            los = []
            his = []
            rgbs = []
            exclusivestart = 0
            for cme in elem:
                rgbs.append(eval(cme.attrib['rgb']))
                vrange = cme.attrib.get('value', '[nan,nan)').lower()
                if not ',' in vrange:
                    if vrange.startswith('[') and vrange.endswith(']'):
                        bnds = eval(vrange)
                        if isinstance(bnds[0], int):
                            bnds.append(bnds[0] + 1e-20)
                    elif vrange.startswith('[') and vrange.endswith(')'):
                        bnds = eval(vrange[:-1] + ']')
                        if isinstance(bnds[0], int):
                            bnds.append(bnds[0] + 1e-20)
                    else:
                        title = xmlcmap.attrib.get('title', 'unknown')
                        msg = f'Not sure what to do with {vrange} on {title}'
                        raise ValueError(msg)
                elif vrange.startswith('[') and vrange.endswith(')'):
                    bnds = eval(vrange[:-1] + ']')
                elif vrange.startswith('(') and vrange.endswith(')'):
                    bnds = eval('[' + vrange[1:-1] + ']')
                    exclusivestart += 1
                los.append(bnds[0])
                his.append(bnds[1])

            edges = np.append(los, his[-1])
            if np.isneginf(los[0]):
                edges[0] = 2 * edges[1] - edges[2]
            if np.isneginf(his[-1]):
                edges[-1] = 2 * edges[-2] - edges[-3]
            cmap, norm = mc.from_levels_and_colors(edges, np.array(rgbs) / 255)
            if np.isneginf(los[0]):
                cmap.set_under(cmap(0))
            if np.isposinf(his[-1]):
                cmap.set_over(cmap(1))
            if exclusivestart > 0:
                print('WARN:: Inclusive left, but BoundaryNorm is exclusive left')
    return cmap, norm


def getnasacmaps(key='', nodata=False):
    import xml.etree.ElementTree as ET
    import requests
    import re

    rurl = 'https://gibs.earthdata.nasa.gov/colormaps/v1.3'
    r = requests.get(rurl)
    rtext = r.text
    hrr = re.compile('href="([^"]+?\\.xml)"')
    paths = hrr.findall(rtext)
    mycmaps = {}
    for path in paths:
        if path.startswith(key):
            pkey = path[:-4]
            print(path)
            cr = requests.get(rurl + '/' + path)
            ctext = cr.text    
            nasacmaps = ET.fromstring(ctext)
            for nasacmap in nasacmaps:
                title = nasacmap.attrib.get('title', 'unknown')
                if title.lower() == 'no data' or nodata:
                    continue
                try:
                    cmap, norm = xmlcmap2cmap(nasacmap)
                    mycmaps[pkey + ':' + title] = {'cmap': cmap, 'norm': norm}
                except Exception as e:
                    print('ERROR::', e)
    return mycmaps


if __name__ == '__main__':
    import numpy as np
    import matplotlib.pyplot as plt
    exmaps = getnasacmaps('ASTER')
    plt.pcolormesh(np.array([[1, 400, 800], [1200, 4000, 8000]]), **exmaps['ASTER_GDEM_Color_Index:Elevation'])