Source code for geonode.documents.exif.utils

#########################################################################
#
# Copyright (C) 2016 OSGeo
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
#########################################################################

import os
import logging

from slugify import slugify
from datetime import datetime


[docs]
logger = logging.getLogger(__name__)



[docs]
ABSTRACT_TEMPLATE_MODEL_DATE_LATLON = "Image shot by {model} on {date} at {lat}, {lon} (latitude, longitude)"


[docs]
ABSTRACT_TEMPLATE_MODEL_DATE = "Image shot by {model} on {date}"


[docs]
ABSTRACT_TEMPLATE_MODEL = "Image shot by {model}"


[docs]
ABSTRACT_TEMPLATE_DATE = "Image shot on {date}"




[docs]
def convertExifDateToDjangoDate(date):
    a = list(date.replace(" ", "T"))
    a[4] = "-"
    a[7] = "-"
    a[10] = "T"

    return datetime(
        int("".join(a[0:4])),
        int("".join(a[5:7])),
        int("".join(a[8:10])),
        int("".join(a[11:13])),
        int("".join(a[14:16])),
    )




[docs]
def convertExifLocationToDecimalDegrees(location, direction):
    if location:
        dd = 0.0
        d, m, s = location
        dd += float(d)
        dd += float(m) / 60.0
        dd += float(s) / 3600.0

        if direction:
            if direction.lower() == "s" or direction.lower() == "w":
                dd = dd * -1.0
        return dd
    else:
        return None




[docs]
def exif_extract_metadata_doc(doc):
    if not doc:
        return None

    if not doc.files:
        return None

    _, ext = os.path.splitext(os.path.basename(doc.files[0]))

    if ext[1:] in {"jpg", "jpeg"}:
        from PIL import Image, ExifTags

        img = Image.open(doc.doc_file.path)
        exif_data = {ExifTags.TAGS[k]: v for k, v in img._getexif().items() if k in ExifTags.TAGS}

        model = None
        date = None
        keywords = []
        bbox = None
        lat = None
        lon = None
        abstract = None

        if "DateTime" in exif_data:
            date = exif_data["DateTime"]
        elif "DateTimeOriginal" in exif_data:
            date = exif_data["DateTimeOriginal"]
        elif "DateTimeDigitized" in exif_data:
            date = exif_data["DateTimeDigitized"]

        if date:
            try:
                date = convertExifDateToDjangoDate(date)
            except Exception:
                logger.error("Could not parse exif date")
                date = None

        if "Make" in exif_data:
            keywords.append(slugify(exif_data["Make"]))

        if "Model" in exif_data:
            model = exif_data.get("Model", None)
            keywords.append(slugify(model))

        if "GPSInfo" in exif_data:
            gpsinfo = {}
            for key in exif_data["GPSInfo"].keys():
                decode = ExifTags.GPSTAGS.get(key, key)
                gpsinfo[decode] = exif_data["GPSInfo"][key]
            if "GPSLatitude" in gpsinfo and "GPSLongitude" in gpsinfo:
                lat = convertExifLocationToDecimalDegrees(gpsinfo["GPSLatitude"], gpsinfo.get("GPSLatitudeRef", "N"))
                lon = convertExifLocationToDecimalDegrees(gpsinfo["GPSLongitude"], gpsinfo.get("GPSLongitudeRef", "E"))
                bbox = [lon, lon, lat, lat]

        abstract = exif_build_abstract(model=model, date=date, lat=lat, lon=lon)

        return {"date": date, "keywords": keywords, "bbox": bbox, "abstract": abstract}

    else:
        return None




[docs]
def exif_build_abstract(model=None, date=None, lat=None, lon=None):
    if model and date and lat and lon:
        return ABSTRACT_TEMPLATE_MODEL_DATE_LATLON.format(model=model, date=date, lat=lat, lon=lon)
    elif model and date:
        return ABSTRACT_TEMPLATE_MODEL_DATE.format(model=model, date=date)
    elif model:
        return ABSTRACT_TEMPLATE_MODEL.format(model=model)
    elif date:
        return ABSTRACT_TEMPLATE_DATE.format(date=date)
    else:
        return None