Get latitude / longitude distance in meters with QGIS

Introduction

Write how to get the value in meters in latitude and longitude of the layer's coordinate system. It is a value that I think will be a reference value. Please let me know if there is another good way.

environment

QGIS 3.4.4

Use Distans Area

layer = iface.activeLayer()
crs = layer.crs()
feature = layer.selectedFeatures()[0]
geom = feature.geometry()
print(geom.length())

area = QgsDistanceArea()
area.setEllipsoid(crs.ellipsoidAcronym())
print(area.measureLength(geom))

Code memorial service in 2.18

layer = iface.activeLayer()
crs = layer.crs()
feature = layer.selectedFeatures()[0]
geom = feature.geometry()

area = QgsDistanceArea()
area.setEllipsoid(crs.ellipsoidAcronym())
area.setEllipsoidalMode(True)
print area.measureLength(geom)

reference

QGIS Documentation: QgsDistanceArea stackexchange: QGIS Python Distance between points QgsDistanceArea.convertMeasurement not enough arguments error