4
You may try to adapt a recipe I've already provided in another answer to programmatically adding custom projections
my_new_projection = QgsCoordinateReferenceSystem("PROJ:+proj=ortho +lat_0=51.470129 +lon_0=-0.452751 +x_0=0 +y_0=0 +a=1188300 +b=1188300 +units=m +no_defs")
my_new_projection.saveAsUserCrs('my_new_projection name') # Save the ...
4
Having different representation systems was indispensable when only paper maps were produced.
Now, with digital maps, that need was divided into two:
One is to define geometric properties on objects located on a curved reference surface, such as defining the length of the shortest line on that surface between two points, the area of a polygon defined by its ...
2
Your proj string should be "+proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs" i.e no comma before +south. You can also use the EPSG code
myProj = Proj('+proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs')
Xutm, Yutm = myProj(X,Y)
print(Xutm, Yutm)
myProj = Proj(32738)
Xutm, Yutm = myProj(X, Y)
print(Xutm, Yutm)
# 323263.484317678 ...
2
Try changing lat_0 and lon_0 values to change the center. Here I use a cylindrical "projection" (it's a sphere...)
# Create a custom projection using a globe with radius 1188300 meters and lon_0 (x) eqal -0.452751 and lat_0 (y) eqal 51.470129
pluto = QgsCoordinateReferenceSystem("PROJ:+proj=ortho +lat_0=51.470129 +lon_0=-0.452751 +x_0=0 +y_0=...
2
In order to be well-defined, a datum needs two things:
A reference surface (commonly a spheroid, also called an ellipsoid
of revolution) with specific parameters for its size and flattening
An attachment to the physical Earth (usually though reference points on the ground and azimuths, or with a link to a geocentric reference frame)
In the case of NAD83, ...
1
Everyone on the web is using one of those 2 coordinate systems. Google pretty much invented 'web mercator' for its maps, while ESRI maps at the time were using all the other coordinate systems as everyone publishing maps using their own local data and coordinate systems did whatever they wanted. Eventually everyone started standardizing their maps to web ...
1
Vector layers and overlays are not automatically reprojected if you change the view. This code should handle that, including going through layer groups and special handling for cluster sources (I have used it when panning a map between two UTM zones):
map.getOverlays().forEach(function(overlay){
if (overlay.getPosition()) {
...
1
I found a solution using gdalwarp. I don't fully understand how my solution works but here is the solution :
2 steps are necessary to georeference my image sphere.tiff with only west longitude degree unit.
gdalwarp -s_srs "+proj=geos +a=6378160 +b=6356775 +lon_0=-135 +h=35785845 +x_0=0 +y_0=0 +pm=-135" -t_srs "+proj=eqc +lon_0=-135 +pm=-135&...
1
You can use proj4js to convert any coordinate system.
Using EPSG code
proj4("EPSG:4326", "EPSG:3857", [2,5]);
Using projestion code
var firstProjection = 'PROJCS["NAD83 / Massachusetts Mainland",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY[&...
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