83
votes
Accepted
Reading shapefile in Python
read your shapefile with Fiona, PyShp, ogr or ...using the geo_interface protocol (GeoJSON):
with Fiona
import fiona
shape = fiona.open("my_shapefile.shp")
print shape.schema
{'geometry': ...
- 50.7k
56
votes
Reading shapefile in Python
I find GeoPandas as the best performer here.
import geopandas as gpd
shapefile = gpd.read_file("shapefile.shp")
print(shapefile)
- 661
49
votes
Accepted
How to polygonize raster to shapely polygons
Use rasterio of Sean Gillies. It can be easily combined with Fiona (read and write shapefiles) and shapely of the same author.
In the script rasterio_polygonize.py
the beginning is
import rasterio
...
- 50.7k
40
votes
Accepted
how to take cell size from raster using python or GDAL or RASTERIO
With PyQGIS
ras = QgsRasterLayer("raster.tif")
pixelSizeX= ras.rasterUnitsPerPixelX()
pixelSizeY = ras.rasterUnitsPerPixelY()
print pixelSizeX
2.11668210081
print pixelSizeY
2.11685012701
With GDAL
...
- 50.7k
34
votes
Accepted
Rasterize a shapefile with Geopandas or fiona - python
You are on the right track and the geopandas GeoDataFrame is a good choice for rasterization over Fiona. Fiona is a great toolset, but I think that the DataFrame is better suited to shapefiles and ...
- 456
28
votes
Accepted
Import error: no module named _gdal_array
Make sure you have numpy installed before you attempt to install the GDAL Python bindings; without numpy, it appears the _gdal_array native code will not be installed.
If you ended up in this ...
- 406
20
votes
Raster reclassify using python, gdal and numpy
Instead of doing the reclassification as a double for loop described by dmh126, do it using np.where:
# reclassification
lista[np.where( lista < 200 )] = 1
lista[np.where((200 < lista) &...
- 886
15
votes
Zooming to layer extent in PyQGIS?
Something like below should work.
vLayer = iface.activeLayer()
canvas = iface.mapCanvas()
extent = vLayer.extent()
canvas.setExtent(extent)
- 6,974
12
votes
Accepted
How I can reverse numbers in a string without reversing any text?
Something like this should work:
def reverse(s):
items = s.split()
digs = ''.join(i for i in s if i.isdigit())
dr = digs[::-1]
return ' '.join(map(None, items)).replace(digs, dr)
>...
- 8,354
11
votes
Accepted
Rasterizing shapefiles with GDAL and Python?
I tried out your code, slightly modified by me for adapting it to mi data (adding your 'hedgerow' field to my shapefile), and it ran well with only add to your code the line: target_ds = None.
from ...
- 25.8k
10
votes
Use psycopg2 to do loop in postgresql
For one thing, you should generally avoid explicit looping like that in Python whenever possible. Psycopg2's cursor objects support the iterator protocol. This means you can iterate row by row over ...
- 318
10
votes
Accepted
How to add vertex to an existing polyline programatically?
First case: insert new polyline
You have to define the Polyline like so:
pLine = [QgsPoint(1,1), QgsPoint(2,1), QgsPoint(2,2)]
it is a list-of-QgsPoint. After you can put more QgsPoint into the ...
- 1,851
10
votes
Rasterize a shapefile with Geopandas or fiona - python
geocube is a new tool specifically designed for rasterizing geopandas data that wraps rasterio. It simplifies the process and eliminates the need for a template raster.
https://github.com/corteva/...
- 5,607
10
votes
Making ArcPy interactive?
Python window is not an equivalent of the Python shell; hence, you won't be able to use the raw_input there. To implement the interactivity with the user, you may choose any of these alternatives:
...
- 29.4k
10
votes
Accepted
Copy attributes from existing shapefile to new shapefile (Python 2.7.13, GDAL)
1) With ogr, see Fast tip: Filtering features using OGR Python for example
from osgeo import ogr
from os import remove
in_file= "shapefileA.shp"
out_file = "shapefileB.shp"
in_ds = ogr.Open( in_file )...
- 50.7k
9
votes
Accepted
Reading zipped ESRI BIL files with Python
Ok, I'm sorry to post a question and then answer it myself so quickly, but I found a nice set of course slides from Utah State University that has a lecture on opening raster image data with GDAL. For ...
- 4,293
9
votes
Raster reclassify using python, gdal and numpy
Here's a basic example using rasterio and numpy:
import rasterio as rio
import numpy as np
with rio.open('~/rasterio/tests/data/rgb1.tif') as src:
# Read the raster into a (rows, cols, depth) ...
- 91
9
votes
Converting between coordinate systems for LAS file using LASPY
You should check what the scale and offset are for your file. This can be done as follows:
van_taken.header.scale
van_taken.header.offset
This almost looks like an overflow error to me. The lower ...
- 91
9
votes
Accepted
Error using pip install for arcpy: "Could not find a version that satisfies the requirement arcpy...."
arcpy ships with Esri's ArcGIS software package. It is neither free nor open source and, even if you were able to obtain it without an ArcGIS license, you would not be able to use it as it has a built-...
- 8,020
8
votes
Accepted
Arcpy Update Cursor (arcpy.da.UpdateCursor()) not saving changes to 'SHAPE@LENGTH'
In cursors, length is a read-only property.
I couldn't imagine what a predictable outcome would be for setting a new length of a line. Would it just extend the last point out in the bearing from the ...
- 17.7k
8
votes
Accepted
How to create a polygon feature class from polylines in Python ArcGIS?
You need to break it down to points if they're good points and reconstruct. Polylines are made from paths, polygons are made from rings. Although they are created in a similar way they are not ...
- 25.1k
8
votes
Accepted
Permanently add a python toolbox to ArcToolbox
This help topic should get you started -- basically you embed your toolbox in a Python package and install it in your local Python installation. Then your tool should show up automatically under ...
- 17.7k
8
votes
How to count point shp inside polygon shp using Python?
The following approach uses a Search Cursor and Python dictionary to perform the following workflow:
Select points within each polygon feature
Update dictionary with key (OID) and value (point count) ...
- 50.2k
8
votes
Accepted
How to count point shp inside polygon shp using Python?
I can crush this down to 3 lines of code, no cursors required!
import arcpy
arcpy.SpatialJoin_analysis("Site", "points","in_memory/points_SpatialJoin", "JOIN_ONE_TO_MANY", "KEEP_ALL", "", "INTERSECT")...
- 38.4k
8
votes
How to polygonize raster to shapely polygons
Here is my implementation.
from osgeo import ogr, gdal, osr
from osgeo.gdalnumeric import *
from osgeo.gdalconst import *
import fiona
from shapely.geometry import shape
import rasterio.features
#...
- 677
8
votes
Accepted
" ".join(list) not inserting spaces when calculating field
If you want to use the Calculate Field tool (instead of an Update Cursor), what you're assigning to val needs to be an unevaluated python expression. That is, it needs to be identical to the string ...
- 8,020
8
votes
SQL queries in PostGIS database layer using Python and QGIS
Adding PostGIS table to a QGIS map
In a QGIS plugin I would use QgsDataSourceURI from the pyqgis API. Here is some snippet form a project I worked on.
Database connection is wrapped in a function. ...
- 7,291
8
votes
Accepted
Saving python Rtree spatial index to file?
Is the built-in disk serialization an acceptable solution?
Make an index and flush it to disk:
from rtree.index import Index
idx = Index('filename')
idx.insert(0, (1, 2, 3, 4))
idx.get_bounds()
# [1....
- 3,857
8
votes
Accepted
python GDAL 'GetDriverByName', argument 1 of type 'char const *'
Because you imported unicode_literals, you're passing a unicode literal to GDAL which is expecting a string literal.
So, explicitly cast the 'GTiff' arg to a str.
E.g.
>>> from ...
- 51.7k
7
votes
Accepted
Increasing speed of Python scripts using arcpy
I have wanted to comment first, but then it seemed more appropriate to wrap it to be an answer (even though it might be incomplete).
I've run your code on my machine (top hardware laptop with SSD) ...
- 29.4k
Only top scored, non community-wiki answers of a minimum length are eligible