Hi,
I am using m.proj on a .csv file containing magnetic and gps data
(x,y,z1,z2) to convert coordinates from UTM Zone 31N (EPSG 32631) to
Lambert 72 (Belgium), EPSG 31370.
GRASS 6.4.3RC3 (2013) Ubuntu Release 12.04 (precise) 32-bit.
The input data file contains X and Y coordinates in UTM Zone 31N, with
columns z1 for magnetic readings, and z2 for elevation.
Grass Location 13009 created using EPSG code 32631
v.info report following v.in.ascii
+----------------------------------------------------------------------------+
Layer: kes1with105melevation@user1
Mapset: user1
Location: 13009
Database: /home/john/grassdata
Title:
Map scale: 1:1
Map format: native
Name of creator: john
Organization:
Source date: Wed Sep 18 20:56:03 2013
----------------------------------------------------------------------------
Type of Map: vector (level: 2)
Number of points: 180396 Number of areas: 0
Number of lines: 0 Number of islands: 0
Number of boundaries: 0 Number of faces: 0
Number of centroids: 0 Number of kernels: 0
Map is 3D: Yes
Number of dblinks: 1
Projection: Universal Transverse Mercator (zone 0)
N: 5624356.51 S: 5624234.54
E: 578607.33 W: 578473.65
B: -100.9 T: 96.8
m.proj in location 13009
m.proj input=/media/VAIO/DATA/kes1with105melevation_out.csv
output=kes1with105melevation_out_projected fs=, proj_in=+proj=utm
+zone=31 +datum=WGS84 +units=m +no_defs proj_out=+proj=lcc
+lat_1=51.16666723333333 +lat_2=49.8333339 +lat_0=90
+lon_0=4.367486666666666 +x_0=150000.013 +y_0=5400088.438 +ellps=intl
+towgs84=-106.869,52.2978,-103.724,0.3366,-0.457,1.8422,-1.2747 +units=m
+no_defs
Switching to my Belgium Lambert 72 Location created using EPSG code
31370
v.in.ascii -z --overwrite
input=/home/john/kes1with105melevation_out_projected
output=kes1with105melevation_out_projected fs=, skip=1 columns=x double,
y double, z1 double, z2 double z=3
when displaying the new vector on top of the background map and survey
perimeter the vector is c.100m to the south-east of where it should be
(see attached screengrab).
I have checked the proj.4 parameters in usr/share/proj/epsg, and these
appear to be correct:
32631 = +proj=utm +zone=31 +datum=WGS84 +units=m +no_defs
31370 = +proj=lcc +lat_1=51.16666723333333 +lat_2=49.8333339 +lat_0=90
+lon_0=4.367486666666666 +x_0=150000.013 +y_0=5400088.438 +ellps=intl
+towgs84=-106.869,52.2978,-103.724,0.3366,-0.457,1.8422,-1.2747 +units=m
+no_defs
There have been past exchanges relating to errors in the proj.4
parameters for Belgium Lambert 72 31370, but here they seem to be
correct. It's probable I am making an error somewhere, either missing an
intermediate process or getting some of the parameters incorrect along
the way.
Can anyone help?
Cheers,
John
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