Tyf.ifd

GeoKeyModel

Mapping of named tuple to be used with geotiff ModelPixelScaleTag, ModelTiepointTag and ModelTransformationTag.

>>> import tyf
>>> from Tyf import ifd
>>> tif = Tyf.open("test/CEA.tif")
>>> ifd.GeoKeyModel["ModelTiepointTag"](*tif[0].tiepoints[0])
ModelTiepoint(I=0.0, J=0.0, K=0.0, X=-28493.1667844, Y=4255884.54380, Z=0.0)
>>> ifd.GeoKeyModel["ModelPixelScaleTag"](*tif[0]["ModelPixelScaleTag"])
ModelPixelScale(ScaleX=60.022136983193, ScaleY=60.022136983193, ScaleZ=0.0)

Transform

def Transform(obj, x=0., y=0., z=0.)

Transformation between raster and model space using a model transformation matrix applied to raster coordinates plus altitude.

>>> mps = ifd.GeoKeyModel["ModelPixelScaleTag"]
>>> mtt = ifd.GeoKeyModel["ModelTiepointTag"]
>>> Sx, Sy, Sz = mps(*tif[0]["ModelPixelScaleTag"])
>>> I, J, K, X, Y, Z = mtt(*tif[0].tiepoints[0])
>>> matrix = ifd.GeoKeyModel["ModelTransformationTag"](
...     Sx, 0.,  0., X - I * Sx,
...     0., -Sy, 0., Y + J * Sy,
...     0., 0.,  Sz, Z - K * Sz,
...     0., 0.,  0., 1.
... )
>>> ifd.Transform(matrix, 10, 10)
(-27892.945414580587, 4255284.32243236, 0.0)

Arguments:

obj GeoKeyModel["ModelTransformationTag"] - transformation matrix.
x float - pixel column index from left.
y float - pixel row index from top.
z float - altitude value.

Returns:

tuple - projeted coordinates X, Y, Z.

Tag Objects

class Tag(object)

Encode and decode on the fly the _v attribute (see Tyf.encoders and Tyf.decoders modules).

>>> tag = ifd.Tag("GPSLongitude")
>>> tag.value = 5.62347
>>> tag._v
(5, 1, 37, 1, 6123, 250)  # 5/1 deg + 37/1 min + 6123/250 sec
>>> tag.value
5.62347

info

Meaning of tag value if any (see Tyf.values module).

>>> ifd.Tag("PhotometricInterpretation", value=3).info
'RGB Palette'
>>> ifd.Tag("Flash", value=0x000F).info
'Flash fired, compulsory flash mode, return light detected'

init

def __init__(tag_or_key, value=None)

Arguments:

tag_or_key int or string - tag value or keyword.
value any - value of the tag. If None is given, it is set to default value if anyone is defined.

read

@staticmethod
def read(fileobj, byteorder)

Extract an IFD tag from buffer current position. Buffer position is adjusted to the end of IFD entry before returning the value.

Arguments:

fileobj buffer - a python file object.
byteorder string - ">" if big-endian used else "<".

Returns:

Tyf.ifd.Tag - tag instance.

calcsize

def calcsize()

Return tag value size in bytes when packed.

pack

def pack(byteorder)

Return a tuple containing packed IFD base entry [tag, type, count], packed value and the info if value have to be written in IFD entry or data.

>>> ttc, val, ofs = ifd.Tag("GPSLongitude", value=5.62347).pack(">")
>>> ttc.hex()
'0004000500000003'
>>> val.hex()
'00000005000000010000002500000001000017eb000000fa'
>>> #   5,      1,     37,      1,   6123,    250
>>> # 5/1 deg   + 37/1 min         + 6123/250 sec
>>> ofs
True

Arguments:

byteorder string - ">" if big-endian used else "<".

Returns:

tuple - packed ifd entry, packed value, is offset boolean

Ifd Objects

class Ifd(dict)

Provide a very similar python dict interface to create and store IFD tags with automatic sub IFD management. exfT, gpsT and itrT are Tyf.ifd.Ifd attributes (sub IFD) for Exif, GPS and Interoperability tags.

>>> i = ifd.Ifd()
>>> i["GPSLongitude"] = 5.62347  # --> GPS IFD
>>> i["FlashpixVersion"] = None  # None will set default value --> Exif IFD
>>> i
{}
>>> i.gpsT
{'GPSLongitude': <IFD tag GPSLongitude:5.62347>}
>>> i.exfT
{'FlashpixVersion': <IFD tag FlashpixVersion:b'0100'>}
>>> i.get("GPSLongitude")  # get method returns tag object
<IFD tag GPSLongitude:5.62347>
>>> i["GPSLongitude"]  # __getitem__ interface returns the python value
5.62347
>>> i.pop("FlashpixVersion")  # delete "FlashpixVersion" tag
<IFD tag FlashpixVersion:b'0100'>
>>> hasattr(i, "exfT")  # empty exfT sub IFD attribute removed
False

raster_loaded

True if raster is loaded

tiepoints

Geotiff tiepoint list

set_location

def set_location(lon, lat, alt=0.)

Set GPS IFD tags according to given longitude, latitude and altitude. If no GPS IFD exists, it is created according to version (2, 2, 0, 0).

>>> i = ifd.Ifd()
>>> i.set_location(5.62347, 45.21345, 12)
>>> for t in i: print(t)
...
<IFD tag GPSVersionID:(2, 2, 0, 0)>
<IFD tag GPSLatitudeRef:'N'>
<IFD tag GPSLatitude:45.21345>
<IFD tag GPSLongitudeRef:'E'>
<IFD tag GPSLongitude:5.62347>
<IFD tag GPSAltitudeRef:0 - Above sea level>
<IFD tag GPSAltitude:12.0>

Arguments:

lon float - longitude in decimal degrees
lat float - latitude in decimal degrees
alt float - altitude in meters

get_location

def get_location()

>>> i = ifd.Ifd()
>>> i.get_location()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "X:/path/to/Tyf/ifd.py", line 568, in get_location
    raise Exception("No location data found")
Exception: No location data found
>>> i.set_location(5.62347, 45.21345, 12)
>>> i.get_location()
(5.62347, 45.21345, 12.0)

Returns:

tuple - longitude, latitude and altitude.

Raises:

Exception - if no GPS IFD found.

url_load_location

def url_load_location(url, **kwargs)

Return a static map image data from map provider.

>>> from Tyf import ifd
>>> i = ifd.Ifd()
>>> i.set_location(5.62347, 45.21345, 12)
>>> # below a mapbox-static-map url centered on [lon, lat] with a red
>>> # pin, width, height and zoom to be specified on call
>>> url = "https://api.mapbox.com/styles/v1/mapbox/outdoors-v11/static"
... "/pin-s+f74e4e(%(lon)f,%(lat)f)/%(lon)f,%(lat)f,%(zoom)d,0"
... "/%(width)dx%(height)d?access_token=%(token)s"
>>> data = i.url_load_location(
...    url, zoom=15, width=600, height=400, token="xx-xxxxxx-xx"
... )
>>> with io.open("dump.png", "wb") as f:
...    f.write(data)

Arguments:

url str - map provider url containing %(lon)f and %(lat)f format expression to be replaced by longitude and latitude found in GPS data.
**kwargs dict - key-value pairs to match entries in url according to python string formatting.

Returns:

bytes|str - Image data.

dump_location

def dump_location(name, url, **kwargs)

Dump a static map image from map provider into filesystem.

Arguments:

name str - a valid filepath.
url str - map provider url containing %(lon)f and %(lat)f format expression to be replaced by longitude and latitude found in GPS data.
**kwargs dict - key-value pairs to match entries in url according to python string formatting.