地理坐标表示方法
LatLon的Python项目详细描述
功能
表示地理坐标（纬度和经度）的方法，包括：
- Convert lat/lon strings from almost any format into a LatLon object (analogous to the datetime library’s stptime method)
- Automatically store decimal degrees, decimal minutes, and degree, minute, second information in a LatLon object
- Output lat/lon information into a formatted string (analogous to the datetime library’s strftime method)
- Project lat/lon coordinates into some other proj projection
- Calculate distance and heading between lat/lon pairs using either the FAI or WGS84 approximation
- Create a new LatLon object by offsetting an initial coordinate by a distance and heading
- Subtracting one LatLon object from another creates a GeoVector object with distance and heading attributes (analogous to the datetime library’s timedelta object)
- Adding or subtracting a Latlon object and a GeoVector object creates a new LatLon object with the coordinates adjusted by the GeoVector object’s distance and heading
- GeoVector objects can be added, subtracted, multiplied or divided
安装
latlon只在python 2.7中测试过
通过PIP安装：
$ pip install LatLon
需要以下非标准库：
- pyproj
使用说明
使用latlon主要是通过类latlon来实现的，该类旨在容纳 纬度和经度对象。使用此方法可以将字符串转换为latlon对象 string2laton，并使用string2geocord指向latitude或longitude对象。或者，拿铁条 对象可以通过减去两个latlon对象，或加上或减去latlon对象来构造。 以及一个geoviector对象。
经纬度结构
经度构造的纬度分别通过latitude和longitude类。你可以 以十进制度数、度数和分钟的任意组合传递纬度或经度坐标，或 度分秒。或者，可以使用函数string2geocord传递格式化字符串。 对于包含单个纬度或经度的字符串，或者对于表示 纬度和经度。
字符串格式：
string2laton和string2geocoord都采用formatter字符串，该字符串松散地基于format 在datetime的strftime函数中使用的关键字。指示符（例如h或d）放在 一个特定的分隔符（%），用于指定坐标字符串的格式。可能的 值如下：
H is a hemisphere identifier (e.g. N, S, E or W)
D is a coordinate in decimal degrees notation (e.g. 5.833)
d is a coordinate in degrees notation (e.g. 5)
M is a coordinate in decimal minutes notation (e.g. 54.35)
m is a coordinate in minutes notation (e.g. 54)
S is a coordinate in seconds notation (e.g. 28.93)
Any other characters (e.g. ‘ ‘ or ‘, ‘) will be treated as a separator between the above components.
All components should be separated by the % character. For example, if the coord_str is ‘5, 52, 59.88_N’, the format_str would be ‘d%, %m%, %S%_%H’
重要
一种当前不起作用的格式是半球标识符和度数或十进制度数 不被任何字符分隔。例如，“55259.88N”有效，而“55259.88N”无效。
字符串输出：
latlon和latitude和longitude对象都包含用于输出格式化的 协调。
投影：
使用latlon.project将地理坐标转换为选定的投影。要求你通过 pyproj或basemap投影。
距离和航向计算：
latlon对象有一个distance（）方法，该方法接受第二个latlon对象作为参数。distance（）将 默认情况下，使用WGS84椭球计算两个坐标之间的大圆距离。使用 更近似的FAI球，将^ {EM1}椭圆“EEM”设为“球面”。可以计算初始和反向航向（以度为单位） 以类似的方式使用heading_initial（）和heading_reverse（）方法。或者，减去一 latlon另一个对象将返回一个带有属性heading和distance的geoviector对象。
通过与另一个对象的偏移创建新的Latlon对象：
使用latlon对象的offset（）方法，它将初始航向（以度为单位）和距离（以公里为单位）设置为 在偏移坐标处返回一个新的latlon对象。此外，还可以通过添加或 用地理矢量对象减去latlon对象。
示例
创建一个latlon来自坐标的对象：
>> palmyra = LatLon(Latitude(5.8833), Longitude(-162.0833)) # Location of Palmyra Atoll in decimal degrees
>> palmyra = LatLon(5.8833, -162.0833) # Same thing but simpler!
>> palmyra = LatLon(Latitude(degree = 5, minute = 52, second = 59.88),
>> Longitude(degree = -162, minute = -4.998) # or more complicated!
>> print palmyra.to_string('d% %m% %S% %H') # Print coordinates to degree minute second
('5 52 59.88 N', '162 4 59.88 W')
从格式化字符串创建latlon对象：
>> palmyra = string2latlon('5 52 59.88 N', '162 4 59.88 W', 'd% %m% %S% %H')
>> print palmyra.to_string('d%_%M') # Print coordinates as degree minutes separated by underscore
('5_52.998', '-162_4.998')
执行一些计算：
>> palmyra = LatLon(Latitude(5.8833), Longitude(-162.0833)) # Location of Palmyra Atoll
>> honolulu = LatLon(Latitude(21.3), Longitude(-157.8167)) # Location of Honolulu, HI
>> distance = palmyra.distance(honolulu) # WGS84 distance in km
>> print distance
1766.69130376
>> print palmyra.distance(honolulu, ellipse = 'sphere') # FAI distance in km
1774.77188181
>> initial_heading = palmyra.heading_initial(honolulu) # Heading from Palmyra to Honolulu on WGS84 ellipsoid
>> print initial_heading
14.6907922022
>> hnl = palmyra.offset(initial_heading, distance) # Reconstruct Honolulu based on offset from Palmyra
>> print hnl.to_string('D') # Coordinates of Honolulu
('21.3', '-157.8167')
使用geovestors操作latlon对象：
>> vector = (honolulu - palmyra) * 2 # A GeoVector with 2x the magnitude of a vector from palmyra to honolulu >> print vector # Print heading and magnitude 14.6907922022 3533.38260751 print palmyra + (vector/2.0) # Recreate the coordinates of Honolulu by adding half of vector to palmyra 21.3, -157.8167
版本
1.0.2-使用EclipseIdle在Python2.7上测试。有什么问题请告诉我。
变更日志
1.0.2（2014年10月14日）
- Class GeoVector is now an abstract class to ensure that any subclasses use the correct API
- Added methods range180 and range360 to class Longitude to interconvert between longitudes reported -180 to 180 format and those reported in 0 to 360 format. To ensure that all operations such as hemisphere assignment work as expected, longitudes reported in 0 to 360 format are automatically converted into -180 to 180 format when the Longitude object is initialized.
1.0.1（2014年9月2日）
- Fixed issue with where attribute theta in GeoVector was treated in some cases like a heading (i.e. starting with due north and continuing clockwise) even though it was in fact an angle (i.e. starting with (1, 0) and continuing anti-clockwise). The attribute name has now been changed to heading to eliminate confusion. The local variable theta is used for computations involving angle.
- Added testing functions with pytest for class LatLon and GeoVector
- Added almost_equal methods to class LatLon and GeoVector to deal with float errors in decimal degree specification
- LatLon.project now returns (x, y) instead of (y, x) to be more consistent with the accepted convention.
^{str 1}0.91美元（2014年8月28日）
- degree, minute and second attributes for GeoCoord class are now coerced to type float
^{str 1}0.90美元（2014年8月28日）
- Updated magic methods for GeoCoord class
- Added option for instantiating LatLon from scalars
^{str 1}0.80美元（2014年8月27日）
- Added GeoVector class to handle vectors between two LatLon objects
- Cleaned up __str__ and __repr__ methods for LatLon, Latitude, Longitude, GeoCoord, and GeoVector classes
^{str 1}0.70美元（2014年8月27日）
- Deprecated LatLon.distance_sphere method. From now on use distance(other, ellipse = ‘sphere’) instead
- Added LatLon.bearing method to return the initial bearing between two LatLon objects
- Added LatLon.offset method to return a new LatLon object that is computed from an initial LatLon object plus a bearing and distance
^{str 1}0.60美元（2014年8月27日）
- Added compatibility with comparison, negation, addition and multiplication magic methods
^{str 1}0.50美元（2014年8月20日）
- First release
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