python-cmr 0.4.1

python cmr

python cmr是nasa eosdis的一个易于使用的包装器 Common Metadata Repository API。这个包裹的目的是 通过提供抢先检查的方法来直观地查询api并且不易出错 对于无效输入并处理cmr api所需的url编码。

访问nasa的地球科学元数据非常简单：

>>> from cmr import CollectionQuery, GranuleQuery

>>> api = CollectionQuery()
>>> collections = api.archive_center("LP DAAC").keyword("AST_L1*").get(5)

>>> for collection in collections:
>>>   print(collection["short_name"])
AST_L1A
AST_L1AE
AST_L1T

>>> api = GranuleQuery()
>>> granules = api.short_name("AST_L1T").point(-112.73, 42.5).get(3)

>>> for granule in granules:
>>>   print(granule["title"])
SC:AST_L1T.003:2149105822
SC:AST_L1T.003:2149105820
SC:AST_L1T.003:2149155037

安装

从pypi安装：

$ pip install python-cmr

要从github安装，可以尝试dev分支：

$ git clone https://github.com/jddeal/python-cmr
$ cd python-cmr
$ pip install .

示例

这个库分为两类，collectionquery和granulequery。每一个 类提供了一组用于为cmr生成查询的方法。未提供所有参数 cmr的api包含在这个版本的python cmr中。

collection和granular查询都可以使用以下方法：

# search for granules matching a specific product/short_name
>>> api.short_name("AST_L1T")

# search for granules matching a specific version
>>> api.version("006")

# search for granules at a specific longitude and latitude
>>> api.point(-112.73, 42.5)

# search for granules in an area bound by a box (lower left lon/lat, upper right lon/lat)
>>> api.bounding_box(-112.70, 42.5, -110, 44.5)

# search for granules in a polygon (these need to be in counter clockwise order and the
# last coordinate must match the first in order to close the polygon)
>>> api.polygon([(-100, 40), (-110, 40), (-105, 38), (-100, 40)])

# search for granules in a line
>>> api.line([(-100, 40), (-90, 40), (-95, 38)])

# search for granules in an open or closed date range
>>> api.temporal("2016-10-10T01:02:00Z", "2016-10-12T00:00:30Z")
>>> api.temporal("2016-10-10T01:02:00Z", None)
>>> api.temporal(datetime(2016, 10, 10, 1, 2, 0), datetime.now())

# only include granules available for download
>>> api.downloadable()

# only include granules that are unavailable for download
>>> api.online_only()

# search for collections/granules associated with or identified by concept IDs
# note: often the ECHO collection ID can be used here as well
# note: when using CollectionQuery, only collection concept IDs can be passed
# note: when uses GranuleQuery, passing a collection's concept ID will filter by granules associated
#       with that particular collection.
>>> api.concept_id("C1299783579-LPDAAC_ECS")
>>> api.concept_id(["G1327299284-LPDAAC_ECS", "G1326330014-LPDAAC_ECS"])

颗粒搜索支持这些方法（除了上面的共享方法之外）：

# search for a granule by its unique ID
>>> api.granule_ur("SC:AST_L1T.003:2150315169")
# search for granules from a specific orbit
>>> api.orbit_number(5000)

# filter by the day/night flag
>>> api.day_night_flag("day")

# filter by cloud cover percentage range
>>> api.cloud_cover(25, 75)

# filter by specific instrument or platform
>>> api.instrument("MODIS")
>>> api.platform("Terra")

集合搜索支持这些方法（除了上面的共享方法之外）：

# search for collections from a specific archive center
>>> api.archive_center("LP DAAC")

# case insensitive, wildcard enabled text search through most collection fields
>>> api.keyword("M*D09")

作为将方法链接在一起以设置查询参数的替代方法，可以使用 方法允许您将参数作为关键字参数传递：

# search for AST_L1T version 003 granules at latitude 42, longitude -100
>>> api.parameters(
    short_name="AST_L1T",
    version="003",
    point=(-100, 42)
)

注意：Kwarg键应该与上述示例中方法的名称和值相匹配 如果是需要多个值的参数，则应为元组。

要检查和检索api的结果，可以使用以下方法：

# inspect the number of results the query will return without downloading the results
>>> print(api.hits())

# retrieve 100 granules
>>> granules = api.get(100)

# retrieve 25,000 granules
>>> granules = api.get(25000)

# retrieve all the granules possible for the query
>>> granules = api.get_all()  # this is a shortcut for api.get(api.hits())

默认情况下，响应将以json形式返回，并可作为python字典列表访问。 在发出请求之前，可以指定其他格式：

>>> granules = api.format("echo10").get(100)

颗粒查询和集合查询都支持以下格式：

• json（默认）
• XML
• 回声10
• ISO
• ISO 19115
• CSV
• 原子
• kml
• 本地的

集合查询还支持以下格式：

• dif
• DIF10
• 打开数据
• umm_json
• umm_json_vx_y（例如：umm_json_v1_9）