plate_motion refactoring: remove pkg dependency (#868)

+ add `objects.euler_pole.py`:
   - create the `EulerPole` class/object based on `numpy` and `pyproj` (similar to https://github.com/joferkington/euler_pole/blob/master/euler_pole/euler_pole.py)
   - use matrix rotation to convert the cartesian frame to local ENU frame, to compute the plate motion
   - the above two remove the dependency on `astropy` and `platemotion` (https://github.com/lcx366/PlateTectonic)
   - add references to Pichon et al., 1973, Cox et al., 1986, ESA webpage
   - turn ON "ellipsoid" Earth calculation by default
   - `get_velocity_enu()`: set vu to 0 if assuming spherical Earth (ellps=False)

+ add `tests/objects/euler_pole.py` for the unit tests:
   - test the EulerPole object initiation/conversion
   - test the plate motion calculation against the UNAVCO web calculator
   - add to the circle CI testing

+ `plate_motion.py` and `cli/plate_motion.py`: add published DOI to Stephenson, Liu, et al. (2022).

+ simplify the setup/install section for plate_motion in `setup.py` and `__main__.py`

+ other minor features and bugfixes:
   - utils.utils0.py: add get_azimuth_angle_from_east_north_obs()
   - utils.readfile.sort_dataset_list4velocity(): support velocity file without velocity dataset, e.g. ITRF14enu.h5 file.

Co-authored-by: Zhang Yunjun <yunjunzgeo@gmail.com>

.circleci/config.yml

@@ -51,6 +51,7 @@ jobs:
             export PATH=${CONDA_PREFIX}/bin:${PATH}
             ${MINTPY_HOME}/tests/asc_desc2horz_vert.py
             ${MINTPY_HOME}/tests/objects/ionex.py
+            ${MINTPY_HOME}/tests/objects/euler_pole.py
 
       - run:
           name: Testing MintPy on Example Dataset 1/4 - FernandinaSenDT128 (ISCE/topsStack)

mintpy/__main__.py

@@ -550,10 +550,7 @@ def get_parser():
     get_dem_error_parser(sp)
     get_iono_tec_parser(sp)
     get_local_oscilator_drift_parser(sp)
-    try:
-        get_plate_motion_parser(sp)
-    except ImportError:
-        pass
+    get_plate_motion_parser(sp)
     get_remove_ramp_parser(sp)
     get_s1ab_range_bias_parser(sp)
     get_solid_earth_tides_parser(sp)

mintpy/cli/plate_motion.py

@@ -13,9 +13,9 @@
 
 #########################################  Usage  ##############################################
 REFERENCE = """reference:
-  Stephenson, O. L., Liu, Y. K., Yunjun, Z., Simons, M., Rosen, P. and Xu, X., (2022), The Impact of
-    Plate Motions on Long-Wavelength InSAR-Derived Velocity Fields, Geophys. Res. Lett. (under review)
-    doi:10.1002/essoar.10511538.2
+  Stephenson, O. L., Liu, Y. K., Yunjun, Z., Simons, M., Rosen, P. and Xu, X., (2022),
+    The Impact of Plate Motions on Long-Wavelength InSAR-Derived Velocity Fields,
+    Geophys. Res. Lett. 49, e2022GL099835, doi:10.1029/2022GL099835.
 
   # list of no-net-rotation (NNR) plate motion models (PMMs):
   # ONLY ITRF14 should be used, as Sentinel-1's orbit is in ITRF2014 reference frame.
@@ -26,8 +26,8 @@
     doi:10.1093/gji/ggx136
   MORVEL - Table 1 of Argus et al. (2011) - 56 plates
     Argus, D. F., Gordon, R. G., & DeMets, C. (2011). Geologically current motion of 56
-    plates relative to the no-net-rotation reference frame. Geochemistry, Geophysics, Geosystems, 12(11).
-    doi:10.1029/2011GC003751
+    plates relative to the no-net-rotation reference frame. Geochemistry, Geophysics,
+    Geosystems, 12(11). doi:10.1029/2011GC003751
 """
 
 EXAMPLE = """example: