38
votes
Accepted
Re-project raster in python using GDAL?
So, thanks to @Luke I used the simple line: gdal.Warp(output_raster,input_raster,dstSRS='EPSG:4326') and it works, this was exactly what I was looking for, simple code with few line to execute simple ...
- 1,839
32
votes
Transforming Shapely Polygon and MultiPolygon objects
If you're using pyproj2, it's much easier to use a Transformer. Here's an example:
import pyproj
from shapely.ops import transform
project = pyproj.Transformer.from_proj(
pyproj.Proj(init='epsg:...
- 433
32
votes
Unable to snap vertices and segment in QGIS 3.0
In QGIS 3.0, the snapping settings are accessed through the snapping toolbar.
This is a change from previous versions. In QGIS 2.x they were accessed through Options menu > Snapping Options...
...
- 25k
30
votes
Accepted
Changing shapefiles from geographic (WGS84) to projected (EPSG:2263) coordinate system using QGIS
This answer has four sections:
What you should do to solve the problem and what you should avoid
An example to better illustrate why assigning CRS and reprojecting are not the same
An analogy that ...
- 73.8k
29
votes
Accepted
Extracting EPSG from a raster using gdal bindings in Python
I found the following workaround. I am unsure if it is the most efficient, but it does work for me.
from osgeo import gdal, osr
path = r"C:\temp\test2.tif"
d = gdal.Open(path)
proj = osr....
- 1,357
25
votes
Accepted
Understanding reprojection?
Reprojection in GIS consists in changing the coordinates values of a dataset from one coordinate system to another coordinate system.
Let's take a one dimensionnal case as an exampple. Imagine that ...
- 49.8k
24
votes
Accepted
Calculating area of lat/lon polygons without transformation using GeoPandas
Overview
Since version 0.7.0 geopandas has embedded the pyproj library as the crs object. pyproj, since version 2.3.0, has the ability to calculate the area of arbitrary polygons on a sphere. (see ...
- 1,867
23
votes
How can EPSG:3857 be in meters?
It is a projection of a spheroid on a flat surface. Every projection has strengths and weaknesses and will preserve some elements of direction, distance or area better or worse than others (which is ...
- 33.9k
21
votes
EPSG 3857 or 4326 for Web Mapping
It's confusing when an API says it uses SRID 3857 but gives a location using SRID 4326
Quick way of telling what SRID your lat/lon is in: Look at how big the number & the precision
EPSG:4326 is ...
- 321
20
votes
Converting projected coordinates to lat/lon using Python
When using pyproj, note the differences from various releases in how it is used to transform data. Here are a few examples using new/old capabilities based on the question:
Using pyproj >= 2.2.0
...
- 42.2k
20
votes
Understanding Coordinate Reference System of QGIS Project and Layer
Short answer: there is project CRS and layer CRS:
You can more or less freely choose any project CRS, QGIS handles the rest automatically.
You can't "set" another CRS for your layer (your ...
- 73.8k
20
votes
Accepted
Showing the bounding box for every coordinate system in QGIS
Yes, QGIS holds this information in an SQLite table.
Go the menu layer / data source manager and select Browser then go to where QGIS is installed (like C:\Program Files\QGIS 3.16\) and dig down to ...
- 42.5k
19
votes
Accepted
Auto-select suitable UTM Zone based on Grid Intersection
There's the utm package, a bidirectional UTM-WGS84 converter for python.
It's able to convert a (latitude, longitude) tuple into an UTM coordinate:
import utm
utm.from_latlon(51.2, 7.5)
>>> (...
- 14.4k
19
votes
What does "¢" mean in a coordinate?
Your viewer, or the website, has some problem with the fonts. Perhaps your browser does not get access to the defined fonts. Works for me, though, and this is how it should look:
Coordinates are ...
- 67.9k
18
votes
Accepted
EPSG code for UTM zone
The UTM zones and their respective EPSG codes cover the whole area of their respecive zone from the equator to 84N / 80S. These areas are subdivided by the letters from South to North, and these again ...
- 1,582
18
votes
Opening PRJ file in text editor?
Right click and open with a text editor like notepad (or Notepad ++).
It's not a GIS layer, just some projection metadata on your layer.
A shapefile is made of severall files with some mandatory. The ...
- 7,868
17
votes
Accepted
ST_DWithin Calc Meters - transform or cast?
As described, the answer is "neither", for the following reasons:
Take a spatial table in 4326. Build a spatial index on it. The spatial index is a planar index, consisting of the 2D bounds of the ...
- 19.9k
17
votes
Create spatial polygon grid from spatial points in R
here is a solution using sf and sf::st_make_grid:
library(raster)
library(sf)
e <- as(raster::extent(-125, -65, 25, 49), "SpatialPolygons") %>%
st_as_sf()
grd_lrg <- st_make_grid(e, ...
- 1,733
17
votes
Why do zones differ for WGS84 UTM in Google Earth Pro vs. in QGIS 3.4?
There are 60 UTM Zones, each 6 degrees wide (about 700km at the equator), and stretching from 84 degrees North to 80 degrees South (the poles are reference with the Universal Polar Stereographic grid ...
- 2,988
17
votes
Accepted
Calculate percentage overlap of 2 sets of polygons in R
You're almost there! You can calculate the area of your new intersecting shapes, and then merge this back into your nc object:
# Calculate area and tidy up
intersect_pct <- st_intersection(nc, ...
- 550
17
votes
Accepted
What kind of coordinates are 38,40.1365N, 75,4.23933W?
Mobile devices use WGS84 coordinates, and the coordinates might be displayed in different formats. One of them is DDM format. A comma for separating degree and minute, a dot for decimal. Your ...
- 77.8k
16
votes
Accepted
Creating custom Coordinate System in PostGIS
It's easy here
Look it up on http://www.spatialreference.org
Find it SR-ORG:7069 NAD_1983_HARN_StatePlane_Michigan_South_FIPS_2113_IntlFeet
Click PostGIS spatial_ref_sys INSERT statement
Run that ...
- 7,111
16
votes
Auto-select suitable UTM Zone based on Grid Intersection
Alright, the answer from Antonio above is definitely right and pointed me in the correct direction. Here is the complete code:
# convert_wgs_to_utm function, see https://stackoverflow.com/a/40140326/...
- 714
16
votes
Accepted
Adding Properties to a feature in Google Earth Engine
Yes, you can use the feature.set()option which Feature Overview covers with these examples:
// Make a feature and set some properties.
var feature = ee.Feature(ee.Geometry.Point([-122.22599, 37.17605]...
- 12.1k
16
votes
Accepted
Reprojecting layer using PyQGIS
You can use processing algorithm native:reprojectlayer.
Example:
lyr = iface.activeLayer()
parameter = {
'INPUT': lyr,
'TARGET_CRS': 'EPSG:4326',
'OUTPUT': 'memory:Reprojected'
}
result = ...
- 7,878
15
votes
From shapefile to Python NetworkX?
I might have found a nice Python solution referring to the very shapefile in the question, so I am posting it for future reference.
import networkx as nx
import matplotlib.pyplot as plt
G=nx....
- 843
15
votes
Accepted
What does the default crs being EPSG:3857 in Leaflet mean?
Leaflet can be a bit confusing for hardcore GIS people, since a L.CRS does not represent an abstract CRS. Quoting from the Leaflet docs, it rather...
[...] defines coordinate reference systems for ...
- 10.3k
15
votes
Accepted
Layer disappears when changing from CRS in degrees to CRS in meters in QGIS
Do not use "Set CRS" within layer properties. This does not reproject your data. You only define the CRS there. Means: you tell QGIS that the layer is in a different CRS than it actually is.
...
- 35.2k
15
votes
Accepted
What is meant with EPSG:4326 projection
You've got a good grasp of it. EPSG 4326 (i.e. WGS 84) is not a projection. But if you don't associate a projection to this geographic coordinate system, and naively render the coordinates as x/y ...
- 8,828
15
votes
Accepted
Projection transformation of a shapefile
What went wrong: If you transform, only the vertices are transformed, not the connecting line: this is always drawn as a straight line on the projected map canvas. So it's "path" will differ ...
- 73.8k
Only top scored, non community-wiki answers of a minimum length are eligible