11
votes
Accepted
Converting to EPSG code gives error
PostGIS does not know EPSG 9234.
You can check this with:
select * from spatial_ref_sys where srid = 9234;
But EPSG.io provides handy code snippets to add it https://epsg.io/9234
Just run:
INSERT ...
- 16.3k
11
votes
How QGIS knows my photos were taken in the Southern Hemisphere
As per comment of user2856, a proper EXIF viewer such as ExifTool shows the full EXIF tags, including GPS Latitude: 36 deg 14' 11.80" S and GPS Latitude Ref: South
- 459
9
votes
Accepted
Choosing CRS for area of interest of my project
Go to https://epsg.org/ and define your region of interest, e.g. using box and drawing a rectangular polygon:
You get a (long) list of CRS valid in the defined region.
Decide what kind of projection ...
- 63.1k
8
votes
Accepted
Why recommended transformation is not the most accurate in QGIS?
How is this default picked by QGIS?
QGIS makes a query to PROJ libraries to obtain the list of possible transformations between two reference frames or geodetic datums. Sorting algorithm is ...
- 13.4k
8
votes
Accepted
Changing spatial reference of Map using ArcPy in ArcGIS Pro
You're pretty much there with your code. You just need to apply the SR on the map
ras= "my_layer.tif"
sr=arcpy.Describe(ras).spatialReference
p = arcpy.mp.ArcGISProject(r"\\ptemplate\...
- 16.6k
8
votes
Accepted
Impossibility to transform coordinates in degree with sf [R]
The numbers in your data frame are not in degrees:
> d
lat lon z
1 4943.265 536.1314 400.4730
2 4943.264 536.1307 400.2688
It looks like 4943.265 should be 49 degrees 43.265 ...
- 61.5k
8
votes
Accepted
QGIS: Create custom CRS that divides current co-ordinates by 1000
Rather than messing around making a custom CRS, if you don't mind creating a new layer, you can apply a transform that scales the geometry by 0.001 using the Processing->Vector Geometry->Affine ...
- 63.8k
7
votes
Coordinates appearing off coast of Ireland regardless of projection set
EPSG:2157, EPSG:29902 and EPSG:29903 all have coordinates in meters but your data seems to be in Latitude, Longitude. Try importing them with EPSG4326 and then setting project projection to the one ...
- 1,339
7
votes
Accepted
Wildly incorrect Lat/Long from UTM conversion
Those points are in EPSG:3857 (WGS 84 / Pseudo-Mercator) not EPSG:32617 (WGS 84/ UTM zone 17N).
EPSG:3857 is the CRS of the Google satellite basemap.
Lon, Lats are:
X,Y,id,
-82.7077395893134,41....
- 63.8k
7
votes
Accepted
How to get Amersfoort 28992 in QGIS?
You hit the already classical problem: do not change the layers's CRS, instead use Menu Raster > Projections > Warp (reproject) (in case of raster layers).
Alternatively, you could have the same ...
- 63.1k
6
votes
Difference between converting a projection into WGS84 first before converting it to a intended coordinate system vs. converting projection directly
Provided that you are using images, a resampling occurs each time the image is projected. This can alter the pixel values based on the resampling method used. The more times your reproject the more ...
- 1,337
6
votes
Difference between converting a projection into WGS84 first before converting it to a intended coordinate system vs. converting projection directly
In addition to the answer by @GeoMonkey as it might be a bit misleading: Reprojecting vector data can lead to differences. As for as the coordinates for the vertices are concerned, it is true that ...
- 63.1k
6
votes
Accepted
Georeferencing using coordinates always corresponds to wrong location on reference map in QGIS
Maybe you want to change your target CRS to EPSG:4326 because your target coordinates are given in latitudes and longitudes, not as web Mercator coordinates (EPSG:3857) which you are currently using ...
- 9,536
6
votes
Accepted
Robinson projection in GeoPandas
Use the cartopy library to bring in the Robinson details.
More details on the GeoPandas Docs.
import geopandas as gpd
from cartopy import crs as ccrs
world = gpd.read_file(gpd.datasets.get_path('...
- 1,615
6
votes
Accepted
Finding the correct UTM zone for set of coordinate in R
The points could be in any of the 60 northern UTM zones. I think it has to be northern because the Y coords are positive, but I may be wrong. Anyway...
Convert points to spatial data set:
library(sf)
...
- 61.5k
6
votes
Accepted
Failing reprojecting from EPSG 4326 to EPSG 3857
The problems are that you need to specify the input field names and also that you need to tell the driver to keep the geometry using the -lco GEOMETRY=AS_XY option, otherwise it throws the geometry ...
- 61.5k
6
votes
Accepted
Clean polygons by shape type
If by "weird" you mean "significantly convex" then one approach would be to calculate the ratio of the perimeter or area of the convex hull of each polygon to the perimeter or area ...
- 2,440
6
votes
If my geometry is stored in 4326 / WGS 1984 what should I transform to for the most accurate area in sq m?
Cast to geography and use use ST_Area to calculate area with units m².
SELECT ST_Area('MULTIPOLYGON (((-98.12317899283 26.29444331481,
-98.12355263136 26.29220720658, -98.1274736313 26.29279476234, ...
- 41.6k
5
votes
Reprojecting layer using PyQGIS
If you do not want to use Processing Tools you can do it like:
layer = iface.activeLayer()
source_crs = QgsCoordinateReferenceSystem(layer.crs().authid())
target_crs = QgsCoordinateReferenceSystem(&...
- 32.5k
5
votes
Accepted
QGIS Reproject a set of points in CSV to another CRS
Load the csv as a Delimited Text
As mentioned in the comments by J.R. - Do some visual checks if the data is where it should be - if they are off check the CRS or if Lat/Lng are swapped etc.
Export ...
- 2,191
5
votes
Accepted
Understanding vector re-projection process/steps
QGIS, GDAL and PostGIS are all using the Proj library https://proj.org/. Up till version 4 (Proj4) the conversions were always using WGS84 as an interim projection but it is not the case any more. If ...
- 61.9k
5
votes
Accepted
EPSG.io API for PROJ definitions
You are using the official site epsg.org, not epsg.io that is run by a private company. EPSG/IOPG supports only the standard formats WKT and GML. The epsg.io site supports other kind of definitions ...
- 61.9k
5
votes
Accepted
Checking if a raster is unprojected
Pretty much same approach with GDAL.
from osgeo import gdal
src=gdal.Open('4326.tif')
crs=src.GetSpatialRef()
crs.IsProjected()
- 61.9k
5
votes
Accepted
QGIS Transformations with respect to desired epoch
Make sure you have QGIS compiled against a GDAL/OGR version greater than 3.4:
We can perform the vector transformation with the Convert Format process (you can look it up in the Toolbox even as ...
- 13.4k
5
votes
Accepted
Skip (invalid) features with invalid geometries in project with pyqgis
Processing options shown in your screenshot are not stored in the project file but rather in the processing config settings.
You can add the following lines to your script (after import processing) to ...
- 20.1k
5
votes
Accepted
Failed to reproject/convert a projected shapefile
This is enough to see the problem:
CRS: NA
First 5 geometries:
MULTIPOLYGON (((-11103211 3540951, -11102945 35...
MULTIPOLYGON (((-10981244 3470857, -10981233 34...
The CRS is "NA"...
- 61.5k
5
votes
Custom CRS for artwork in QGIS
If you want to take measurements or do anything based on the units, you better not use any CRS or you might end up with misinterpretation of geographic coordinates, an ellipsoid and whatnot.
Just use ...
- 10.2k
5
votes
How QGIS knows my photos were taken in the Southern Hemisphere
EXIF data doesn't store location as a signed (latitude, longitude) pair. Instead, it stores it using four tags: unsigned latitude, latitude reference (north or south), unsigned longitude, and ...
- 201
5
votes
Accepted
Standard and official list of Coordinate Reference Systems
There is the IOGP's EPSG geodetic registry whose EPSG codes are ubiquitous in the GIS world. Wikipedia article.
Note: The EPSG geodetic registry was originally maintained by EPSG (European Petroleum ...
- 9,207
5
votes
Accepted
Polygons no longer completely overlap after reprojection
As user30184 pointed out, this behavior is due to the fact that only the vertices were transformed. A straight line was then drawn between the transformed vertices when in reality the line should not ...
- 109
Only top scored, non community-wiki answers of a minimum length are eligible