Cone, Orientation, and Quaternion are high priorities for me. If you are planning to implement those in the near future, I'll wait. If not, I may take a crack at them and contribute. Quaternion and Orientation are a bit tricky since it's not yet documented (https://github.com/AnalyticalGraphicsInc/cesium/wiki/CZML-Content#orientation).

1. czml.czml.Clock is not exported, i.e. it's not available as czml.Clock as other primitives are (but czml.CZMLPacket accepts dict of properties for Clock).

2. currentTime, multiplier, range and step attributes have no defaults, so they must be specified.

Example of how I use Clock in my code:

        packet = czml.CZMLPacket(
            id='document',
            version='1.0',
            clock=czml.czml.Clock(
                currentTime=datetime.datetime.now().isoformat(),
                multiplier=1.0,
                range='CLAMPED',
                step='SYSTEM_CLOCK_MULTIPLIER',
            )
        )

There appears to be a copy-n-paste type error in czml.py, line 1514 (version 0.3.2):

p.load(point)

should be

p.load(orientation)

Hi I'm not getting the example in README.rst to work, using python 2.7.

Added an import of json, and changed to capitals on doc = czml.CZML() and moved bb.show = True from initialization to script.

Import the library

from czml import czml
import json

Initialize a document

doc = czml.CZML()

Create and append the document packet

packet1 = czml.CZMLPacket(id='document',version='1.0')
doc.packets.append(packet1)

Create and append a billboard packet

packet2 = czml.CZMLPacket(id='billboard')
bb = czml.Billboard(scale=0.7) #, show=True
bb.show = True
bb.image = 'http://localhost/img.png'
bb.color = {'rgba': [0, 255, 127, 55]}
packet2.billboard = bb
doc.packets.append(packet2)

Write the CZML document to a file

filename = "example.czml"
with open(filename, 'w') as file:
json.dump(doc.data(), file)

I however get an error on last line:
182
183 """
--> 184 raise TypeError(repr(o) + " is not JSON serializable")
185
186 def encode(self, o):

TypeError: <generator object data at 0x0000000004792CA8> is not JSON serializable

@cleder, as described TerriaJS/terriajs#1063 we are trying to figure out how to get vector fields into TerriaJS, like this one:

(See the full Jupyter notebook in case you are interested in how this was generated)

It has been suggested to use CZML, and I'm wondering whether it's best to take the approach suggested to use billboards (scaled/rotated icons), or whether we could use the agi_vector described here: https://github.com/AnalyticalGraphicsInc/cesium/wiki/CZML-Content#agi_vector

Do you have a suggestion of which approach to take?
Could I use your czml python package to write either of these?

I am trying to read a simple czml file (see below)

trying as per the readme

doc = czml.CZML()
with open(fpath, 'r') as f:
doc.loads(f.read())

fails with a ValueError on bb.load(billboard) in czml.pyc

Any suggestions?

Many thanks

simple.czml

(from https://github.com/AnalyticalGraphicsInc/cesium/wiki/CZML-in-Cesium)

[
{
"id":"Headquarters",
"availability":"2012-06-20T16:00:00Z/2012-06-20T16:02:00Z",
"position":{
"cartesian":[
1216469.9357990976,-4736121.71856379,4081386.8856866374
]
},
"billboard":{
"color":{
"rgba":[
0,255,255,255
]
},
"horizontalOrigin":"CENTER",
"image":"http://cesiumjs.org/images/Cesium_Logo.png",
"scale":1.0,
"show":[
{
"interval":"2012-06-20T16:00:00Z/2012-06-20T16:02:00Z",
"boolean":true
}
],
"verticalOrigin":"CENTER"
}
}
]

Maybe with instructions how to convert kml to czml

It would be cool to have some more complex examples. Is there a discussion group where we could ask for contributions?

According to this every interpolatable type should have them.

I’m trying to visualize a polyline in cesium via czml.
The czml I’m trying to load is available at:

https://gist.github.com/ae4c6bf491949e711ab7

unfortunately, I'm not able to visualize it cesium.

Do you have any clue on what is wrong with my file?
here is an attempt to generate the data and visualize them within an ipython notebook.

http://nbviewer.ipython.org/gist/epifanio/232f1f7ae3212ca68353/cesium-czml-test.ipynb

Thanks for your help!!!

The Problem

This is really a question for @cleder. On Build #40 I learned why there are so many tests shaped like this:

with self.assertRaises(Exception):
    foo = czml.Object(args...)

That are commented out. In Python 2.6 and below unittest.assertRaises() expects three arguments, where 2.7 and up are okay with the single argument. As a result it's impossible (or I don't know how) to build unit tests confirming exceptions and type errors are raised with invalid object creation, as in the example above.

Specifically in d6df512 I added a test for setting version on a CZMLPacket as it's instantiated where the documentation is clear that this is only valid on the document object. From personal experience with CZML I've found that setting version on other objects will result in invalid CZML, so it's an important test to have in place:

# Test that version can only be added to the document object (id='document')
with self.assertRaises(Exception):
    doc = czml.CZMLPacket(id='foo', version='1.0')

(this was commented in cd50ef3)

There are a handful of other such unit tests built within a context manager like this currently commented out in test_DateTimeAware, testCone, and testEllipsoid. Presumably they work in 2.7 and up, and presumably they're good tests to have in the suite.

Potential Solutions

1. Only build unit tests that work on all supported versions of Python (e.g. don't use a context manager with unittest.assertRaises())
2. Wrap unit tests that error on Python 2.6 in a version check so they never fire on 2.6 and below
3. Remove Python 2.6 support altogether

We're effectively doing solution 1 right now but it's limiting. I lean toward solution 3 for its simplicity, but I don't know how critical support of 2.6 is among users of this module.

This is the code

# Import the library
from czml import czml
if __name__ == "__main__":
    # Read an existing CZML file
    filename = 'data/simple.czml'
    with open(filename, 'r') as example:
        doc = czml.CZML()
        doc.loads(example.read())

    print(doc)
    pass

Its failing on isinstance(description, Description) on line 1393 in czml.py.
It apparently a unicode string is not an instance of Description.

Errors here:
  File "C:\Users\...\venv\lib\site-packages\czml\czml.py", line 1402, in description
    raise TypeError
TypeError

Here is the CZML file (super_simple.czml).

[
  {
    "id":"document",
    "name":"simple",
    "version":"1.0",
    "clock":{
      "interval":"2012-03-15T10:00:00Z/2012-03-16T10:00:00Z",
      "currentTime":"2012-03-15T10:00:00Z",
      "multiplier":60,
      "range":"LOOP_STOP",
      "step":"SYSTEM_CLOCK_MULTIPLIER"
    }
  },
  {
    "id":"0653255a-81a7-4c2c-b154-f987e54767ac",
    "name":"Accesses",
    "description":"<p>List of Accesses</p>"
  }
 ]

The setup.py file calls out the license as LGPL. Please add a LICENSE file to the Github repository so that Github properly shows the license information.

I'm writing a script to convert bird migration data in CSV files to CZML. It's working well so far, but I'd like to add a description element as per this suggestion from Kevin Ring:
TerriaJS/terriajs#1275 (comment)

When I try to add this to my script here:
https://gist.github.com/rsignell-usgs/d0b1fd95f79204a50814#file-bird2czml-py-L110
I get no errors, but the output CZML file doesn't contain the description.

I looked at the code and it seems like there is some description stuff in there:
https://github.com/cleder/czml/blob/master/czml/test_main.py#L1015-L1017
but I couldn't figure out how to use it.

Is the description element actually implemented?
If so, how do I use it?

In beginning to use this library for automating the generation of CZML documents I've traditionally built by hand I've noticed that the interval attribute, commonly used on many different elements, has not been built out.

I intend to try to build this out against my fork and commit it upstream, but am filing this issue for documentation and discussion. I'm somewhat new to both Python and CZML.

For starters, I assume _interval should be defined within the DateTimeAware class. It's similar to epoch though it has two datetime values instead of one but is still ultimately represented as a string. Is trying to represent both start and stop datetimes of an interval value too complicated, since intrevals in CZML are strings? Example from the CZML Documentation on Intervals:

{
    "id": "myObject",
    "someProperty": [
        {
            "interval": "2012-04-30T12:00:00Z/13:00:00Z",
            "number": 5
        },
        {
            "interval": "2012-04-30T13:00:00Z/14:00:00Z",
            "number": 6
        },
    ]
}

This documentation also shows how intervals can be used generally by taking a given attribute of an object (e.g. a scalar value) and optionally expanding it to be an object with two attributes: an interval and the original value. I'm not entirely sure how best to build this out since it is so generally applicable. Any input would be very helpful!

Note: specifically I have a use case for using this library to generate CZML documents that utilize the clock and loop over a given interval. That's where the Clock pull request originated. Without interval support looping clocks (using LOOP_STOP as the range value) are not possible. Clock support and Interval support were distinct enough that it made sense to split them into two branches.

Is there any advantage to using this over straight JSON besides data validation? I noticed that it makes sure properties are set that are required in some cases, however I also noticed that it completely ignores properties it's not aware of and only supports a very small subset of the current CZML spec.

from pygeoif.geometry import as_shape as asShape

Line 46 of czml.py attempts to import as_shape from pygeoif.geometry. Since the 1.0 release this isn't exported anymore leading to an import error when loading the package.

A quick solution would be to peg pygeoif to version 0.6.
I'm so far unsure what can be used in it's place, but updating the usage would be better in the long term.

I’m trying to visualize a polyline in cesium via czml.
The czml I’m trying to load is available at:

https://gist.github.com/ae4c6bf491949e711ab7

unfortunately, I'm not able to visualize it in cesium.

Is there any way to validate it ?
below an attempt to generate a czml Polyline

http://nbviewer.ipython.org/gist/epifanio/232f1f7ae3212ca68353/cesium-czml-test.ipynb

Why isn't the description field included here:

https://github.com/cleder/czml/blob/master/docs/COMPONENTS.md

Robert