RGeo 0.5.2 和 RGeo::CoordSys::SRSDatabase::ActiveRecordTable

Question

首先，如果这真的很简单，我深表歉意，但我似乎无法弄明白。我正在使用 RGeo 在 UTM 和纬度/经度之间进行转换，就像这样；

 srs_database = RGeo::CoordSys::SRSDatabase::ActiveRecordTable.new

 # create the coordinate factory for the relevant UTM zone
 utm_factory = RGeo::Cartesian.factory(:srid => srid,
                                       :srs_database => srs_database)
 utm_location = utm_factory.point(easting, northing)

 # create the standard WGS84 lat/long coordinate factory
 wgs84_proj4 = '+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs'
 wgs84_factory = RGeo::Geographic.spherical_factory(proj4: wgs84_proj4, :srid => 4326)

 # perform the UTM -> lat/long cast
 RGeo::Feature.cast(utm_location, :factory => wgs84_factory, :project => true)

如您所见，我正在使用 RGeo::CoordSys::SRSDatabase::ActiveRecordTable。

我刚刚升级到 RGeo 0.5.2，我注意到这个类已被弃用。

很公平，但我现在不确定替代方法是什么...我四处搜寻但似乎找不到合适的文档。

此外，我原来的方法对我来说总是有点复杂 - 是否有更简单的方法来完成 UTM -> RGeo 的经纬度转换？

提前致谢!

本

Answer 1

好吧，实际上我很快就解决了这个问题。这对我有用:

 if hemisphere == 'S'
   srid = 32700 + number.to_i
   utm_proj4 = "+proj=utm +zone=#{zone} +south +datum=WGS84 +units=m +no_defs"
 else
   srid = 32600 + number.to_i
   utm_proj4 = "+proj=utm +zone=#{zone} +datum=WGS84 +units=m +no_defs"
 end

 # create both the UTM and lat / long factories (we will project between them)
 utm_factory = RGeo::Cartesian.simple_factory(srid: srid, proj4: utm_proj4)
 wgs84_factory = RGeo::Geographic.spherical_factory(srid: 4326, proj4: '+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs')

 # create the UTM location
 utm_location = utm_factory.point(easting, northing)

 # perform the UTM -> lat/long cast
 RGeo::Feature.cast(utm_location, :factory => wgs84_factory, :project => true)

我正在根据从 spatial_ref_sys 表中提取的 Proj4 字符串创建自己的工厂。

虽然我不确定这是否“正确”，但可能有更好的方法。

但我希望这对某人有所帮助! :)