From a8aa3ea771dc59683483d2a55b45c98b8341e3dd Mon Sep 17 00:00:00 2001
From: XANTRONIX Industrial <xan@xantronix.com>
Date: Fri, 28 Feb 2025 13:07:17 -0500
Subject: [PATCH] Initial commit of rawins.py
---
lib/xmet/rawins.py | 104 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 104 insertions(+)
create mode 100644 lib/xmet/rawins.py
diff --git a/lib/xmet/rawins.py b/lib/xmet/rawins.py
new file mode 100644
index 0000000..954aa9c
--- /dev/null
+++ b/lib/xmet/rawins.py
@@ -0,0 +1,104 @@
+import io
+import re
+import datetime
+
+from xmet.util import each_chunk
+from xmet.afos import RE_ID, RE_ISSUANCE, RE_PRODUCT
+from xmet.sounding import Sounding, SoundingSample
+
+CHUNK_SEP = "\x01"
+CHUNK_STRIP_CHARS = "\x01\x03\x0a\x20"
+
+class RawinsReaderException(Exception):
+ ...
+
+class RawinsChunk():
+ def __init__(self,
+ wfo: str,
+ product: str,
+ station: str,
+ values: list[str]):
+ self.wfo = wfo
+ self.product = product
+ self.station = station
+ self.values = values
+
+class RawinsReader():
+ """
+ A reader for the global `Current.rawins` file provided by UCAR:
+
+ https://weather.rap.ucar.edu/data/upper/Current.rawins
+ """
+ def __init__(self, fh: io.TextIOBase):
+ self.fh = fh
+ self.soundings = dict()
+ self.current = Sounding()
+
+ def parse_chunk(self, text: str) -> RawinsChunk:
+ meta = {
+ 'wfo': None, # NWS forecast office
+ 'product': None, # NWS product code
+ 'station': None # WMO rawinsonde station ID
+ }
+
+ line_index = 0
+
+ #
+ # Split each line in the text chunk. Not all chunks will have the
+ # same amount of metadata, so parse accordingly.
+ #
+ lines = list(map(lambda s: s.strip(), text.split("\n")))
+
+ #
+ # The `Current.rawins` feed from UCAR includes basic AFOS header
+ # information in the first two lines. Validate this. Note the first
+ # line is a sort of sequence number which has no public significance.
+ #
+ match = RE_ID.match(lines[0])
+
+ if match is None:
+ raise RawinsReaderException(f"First chunk line not 3-digit identifier ({lines[0]})")
+ else:
+ line_index += 1
+
+ #
+ # The `Current.rawins` feed from UCAR should also include a product
+ # issuance code indicating the WFO and validity time. This can also
+ # be validated.
+ #
+ match = RE_ISSUANCE.match(lines[1])
+
+ if match is None:
+ raise RawinsReaderException('Second chunk line not product issuance')
+ else:
+ meta['wfo'] = match['wfo']
+ line_index += 1
+
+ #
+ # Finally, sometimes, the `Current.rawins` feed has an AFOS header
+ # which indicates the product code followed by the three-character
+ # WFO code. Capture the product code purely for posterity.
+ #
+ match = RE_PRODUCT.match(lines[2])
+
+ if match is not None:
+ meta['product'] = match['product']
+ line_index += 1
+
+ #
+ # Split each whitespace-delimited column of each line into one big
+ # list of lines for the remainder of the current text chunk.
+ #
+ values = list()
+
+ for line in lines[line_index:]:
+ values.extend(re.split(r'\s+', line))
+
+ return RawinsChunk(meta['wfo'],
+ meta['product'],
+ meta['station'],
+ values)
+
+ def each_chunk(self) -> list[Sounding]:
+ for text in each_chunk(self.fh, CHUNK_SEP, CHUNK_STRIP_CHARS):
+ yield self.parse_chunk(text)