Tagged Questions
2
votes
1answer
51 views
How to sort features in a layer using OGR/Python?
How can I sort the features of an ogr layer by the values of a field?
I tried naive variations of
def sortlayer(ds, layer, field):
lname = layer.GetName()
lsort = ds.ExecuteSQL(b'select * ...
0
votes
2answers
88 views
How to install Shapely, but got stuck into Python language
I have a MAC OSX 10.7.5 and am trying to learn how to use QGIS.
Following a couple of tutorials I came to know I have to install shapely.
I followed the instructions by the multi-cited ...
0
votes
0answers
48 views
ogr.GetDriverByName('FileGDB') returns None
I installed:
gdal-110-1600-x64-core.msi
GDAL-1.10.0.win-amd64-py2.7.msi
gdal-110-1600-x64-filegdb.msi
from www.gisinternals.com
I can open my gdb on the command line:
C:\data>ogrinfo ...
1
vote
2answers
66 views
How can I convert a ascii file to geotiff using Python?
I have a ascii raster format file. For example:
ncols 480
nrows 450
xllcorner 378923
yllcorner 4072345
cellsize 30
nodata_value -32768
43 2 45 7 3 56 2 5 23 65 34 6 32 54 57 34 2 2 54 6
35 45 65 34 ...
1
vote
1answer
53 views
Python GDAL/OGR: WGS84 & meters units
I'm dealing with shapefiles projected in:
GEOGCS["GCS_WGS_1984",
DATUM["WGS_1984",
SPHEROID["WGS_84",6378137,298.257223563]],
PRIMEM["Greenwich",0],
...
2
votes
0answers
66 views
Use GDAL/Python to add rasters (tiff) to an ESRI File Geodatabase
I'm using GDAL python to create a bunch of tiff files from a netcdf file.
def modelout_to_geotif(netcdfile, outdir, VarName):
""" Given the path to the netcdf output,
produces geotiffs for ...
0
votes
1answer
54 views
Python GDAL: degrees to meters without reprojecting
I am trying to get senseful results in my Python script. I want to measure distance between features in a shapefile. I'm working with the SRS: GCS_WGS_1984, so my units are in degrees. But for the ...
0
votes
0answers
16 views
How to set transparent geotiff by GDAL? [duplicate]
How to set transparent geotiff by GDAL?
I get png with transparent background but i use gdal_translate - background is with.
1
vote
1answer
51 views
How to set a spatial filter with Python/GDAL?
Is there a way with GDAL (Python) to set a spatial filter (bounding-box) on a raster before I process it? I want to read it as an array.
BandReadAsArray(band, xoff=0, yoff=0, win_xsize=None, ...
5
votes
1answer
134 views
Python - OGR: Transform coordinates from meter to decimal degrees
I have a point in a shapefile. The shapefile is in a WGS_1984_Web_Mercator Projected Coordinate System. I want to get the coordinates of that point in decimal degrees with GDAL/OGR in Python.
I am ...
1
vote
1answer
54 views
Python GDAL: find out spikes and pits in DEM
I'm working with on a DEM (Geotiff) in Python GDAL, and I'd like to find out the spikes or pits in my terrain.
I have no idea how to proceed, does anyone have good algorithm to help me out?
Thanks,
eo
...
0
votes
0answers
33 views
Python GDAL/OGR: check lines geometries connectivity
I'm working with shapefiles representing roads, so basically it's stored as (poly)lines.
I need to perform a road connectivity checking. In other words, I want to ensure that roads meant to ...
2
votes
1answer
77 views
GDAL/Python: How do I get coordinate system name from SpatialReference?
In Python, using GDAL, I've extracted a raster's projection as a WKT string as follows:
wkt = dataset.GetProjection()
# wkt is ...
1
vote
1answer
26 views
python gdal_polygonize error
I am trying to use gdal_polygonize to create a polygon from a binary raster.
My code is:
os.system('gdal_polygonize.py ' + filename + ' -f ESRI Shapefile ' + shapefile)
where filename is a string ...
1
vote
1answer
28 views
OGR UnionCascaded gives strange lines (flat polygons)
I'm using OGR to perform a union using UnionCascaded. All my polygons have been created by GDAL polygonize which ensures that all polygons follow pixel edges and should therefore align nicely. But I ...
1
vote
1answer
91 views
GDAL bindings problem with ArcMap 10.1 Python tool
I'm really getting mad with this. ArcGIS sometimes can be so just...irritating!
Forgive me if this question is by any means duplicating this one or similar ones, but I really can't find my way out of ...
0
votes
1answer
84 views
Is it possible to use GDAL to combine (rather than mosaic) rasters
Is there a GDAL command which can combine multiple rasters so that a unique output value is assigned to each unique combination of input values, like the combine command in ArcGIS?
gdal_merge seems ...
2
votes
3answers
103 views
How to test if geometry is inside another?
I need to tell whether geometries from a shapefile are inside other geometries or not.
For example, I want to test if there are trees (represented as points in trees.shp) inside the urban areas ...
0
votes
1answer
32 views
Local variance image in python using gdal and a running window approach
I want a local variance image with a 3x3 of a geospatial raster image using python. My approach so far was to read in the raster band as an array, then using matrix notation to run a moving window and ...
1
vote
1answer
99 views
Python GDAL: Save array as raster with projection from other file
I have an array of data, and for each datapoint I know the latitude and longitude. I'd like to save it as a GTiff with the same projection as other rasters I have. This is what I've tried so far, but ...
2
votes
1answer
93 views
OGR - Weird GeomType -2147483645 on polygon shapefile
I am trying to import a shapefile (multipolygon) in an app with ogr but I got an error about invalid geom type. If I inspect the data with ogr like this:
datasource = ogr.Open("c:\\temp\\data.shp")
...
1
vote
4answers
103 views
Get vector features inside a specific extent
The problem:
I have a very large vector layer with many features and a much smaller raster layer in a defined region. I want to get only those vector features which are within the raster layers ...
6
votes
1answer
181 views
How to get raster corner coordinates using Python GDAL bindings?
Is there a way to get the corner coordinates (in degrees lat/long) from a raster file using gdal's Python bindings?
A few searches online have convinced me that there is not, so I have developed a ...
0
votes
1answer
52 views
How to save image to disk with with gdal_translate?
I do:
import os
from gdal import *
filename = 'c:/rast.jpg'
outputTif = 'c:/rastOut.tif'
os.system('gdal_translate filename outputTif')
but it returns "1".
gdal_translate doesn't save the image ...
1
vote
1answer
79 views
Python GDAL: Write new raster using projection from old
If I read in a raster image as an array, then make some changes to the values in the array, how do I then save the array as a raster with the same projection information as the original array?
In ...
1
vote
2answers
185 views
Merging many rasters using Python
I have a list of many many rasters. I want to have a simple and easy to understand script that takes this and merges it into one big mosaic. I found a similar question but the accepted answer adivises ...
0
votes
1answer
126 views
How to clip raster by multiple polygons in multi rasters?
Using QGIS, I want to clip a raster by multiple polygons contained in a single shapefile. I read that gdalwarp can clip my raster by multiple polygons BUT the output is a single merged clipped raster. ...
1
vote
1answer
54 views
GeoDjango - Use GDAL python binding in the shell
I would like to use the GDAL python binding in my GeoDjango site. The aim of this is to use ogr2ogr capabilities in a script. I am on windows 7 so I have installed GDAL-1.9.2.win32-py2.7 downloaded ...
2
votes
1answer
242 views
GDAL_translate: converting ESRI GRID to Geotiff in batch
The Challenge:
To batch convert 1000 rasters in ESRI Grid binary to Geotiff using either using a batch file or Python 2.7 without ArcGIS/Arcpy module.
The Tools:
Win7Pro, GDAL 1.9.2 (via OSGeo4W), ...
0
votes
1answer
127 views
How do i use gdal2tiles for creating tilecache?
I want to create tiled cache from raster file, so i downloaded gdal2tiles.py.
Now i don't get what (and how) i must do with that python script file.
3
votes
1answer
64 views
Setting Band Statistics on Raster Image (GeoTIFF)
After doing calculations on a raster and saving it, the image statistics are wrong and need updating.
I find examples saying that this should do the job, like in this example:
...
2
votes
1answer
51 views
OGR CreateLayer returns TypeError
I'm trying to create a shapefile layer based on the spatial projection of an already existing raster. (Ultimately, this will be used in gdal.Polygonize to get a shape from my raster data.) However, I ...
4
votes
1answer
89 views
Programmatic raster-vector calculation
I currently use GRASS' r.mapcalc to find the difference between vector and raster data using a loop and temporary files and layers.
Is it possible to do the core calculation between raster with a ...
2
votes
2answers
163 views
What's the best projection for rasterization of random latitude and longitude data in the northern Atlantic?
I have a dataset in the WGS84 geographic coordinate system that I would like to interpolate along a grid using Python.
It appears gdal_grid is not available through the Python bindings, so I plan to ...
1
vote
1answer
101 views
calculating terrain elevation line
I found too many hits on the web to even see the right direction to go.
I have to provide a small proxy server serving requests for a line
of terrain elevation data between two coordinates.
It is a ...
0
votes
0answers
106 views
How to re-project the EASE (Equal Area Scalable Earth) grid with a ~25 km cylindrical projection to WGS84 0.25 degree?
I have nc files ,here is one file https://echange-fichiers.inra.fr/get?k=LUfqiyO1Dl7az5bihnS. from the metadata ,the projection is cylindrical and the resolution is 25 km:
...
1
vote
1answer
213 views
Slow tiles generation for leaflet js
I am currently trying to use leaflet to display images (jpeg or png) instead of maps, I have followed the instructions on this blog post to create the tiles using gdal2tiles.py here is the code we ...
0
votes
0answers
84 views
Regional statistics from a dataset (point inside a polygon aka region)
I am relatively new to GIS and I am trying to do some geographical analysis on same data I've collected. The dataset I have consists essentially in a file with the following format:
...
10
votes
1answer
664 views
How do I get the pixel value of a GDAL raster under an OGR point without NumPy?
I am working on a computational model of the abundance of wild pollinators across a landscape. The model itself is complete, and I am now struggling with a post-processing step.
I have my GDAL ...
4
votes
2answers
190 views
Create subsetted multiband image from multiple files using gdal or python?
Given a time series of an area (single band), how you subset them and combine the subsets into a single multiband file (eg. vrt) using gdal or gdals' bindings for python?
5
votes
1answer
96 views
GDAL/OGR Determine if dataset is raster or vector
I am writing a script using the GDAL/OGR Python bindings and it is possible that the user may provide a raster dataset or a vector dataset as input. If the user provides a vector dataset, the script ...
2
votes
0answers
274 views
gdal ImportError in python on Windows
Trying to import gdal for Python 2.7.3 on Windows XP:
>>> import gdal
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File ...
9
votes
2answers
417 views
Gdal Dataset.ReadAsArray() crashes Python
I am using Python 2.6.5 (32bit) with Numpy 1.3 and Gdal 1.9.1 installed on Windows 7 64bit. I am trying to read an 800 MB Imagine (.img) raster dataset into a Numpy array to do some raster algebra, ...
3
votes
1answer
160 views
Python equivalent of gdalbuildvrt
Is there a way to perform the same task as the gdalbuildvrt utility using GDAL Python bindings? So far I have not found any way to do this other than creating a vrt of a single dataset and manually ...
5
votes
0answers
100 views
How to detect a GDAL/OGR 'Warning'?
When I run a batch script using a GDAL/OGR program, I can detect if an error occured by checking ERRORLEVEL for the value 1.
When using GDAL/OGR in python or .NET, I get an exception when an error ...
3
votes
2answers
144 views
How to call gdal_retile from Python code?
I am trying to call gdal_retile from my Python code like this:
import gdal_retile
and in main:
gdal_retile.main("-v -r bilinear -levels 4 -ps 2048 2048 -co \"tiled=YES\" -targetDir pyramid ...
7
votes
3answers
546 views
GDAL and Python: How to get coordinates for all cells having a specific value?
I've got an Arc/Info Binary Grid---specifically, an ArcGIS flow accumulation raster---and I'd like to identify all cells having a specific value (or in a range of values). Ultimately, I'd like a ...
9
votes
2answers
793 views
How to call gdal_translate from Python code?
Is it possible to use some gdal API to call gdal_translate from Python code? I do not mean simply executing the gdal_translate.py from the file system, but rather call it somehow in code so I do not ...
2
votes
0answers
90 views
projection discrepancy with gdal (1.9) and proj4
I boiled the problem down to that python example:
import sys
try:
from osgeo import gdal
from osgeo import osr
except:
import gdal
import osr
if __name__ == '__main__':
version_num = ...
2
votes
1answer
134 views
gdal.py as part of bat script in windows 7
I need to run the following bat file from a MS4W shell which has gdal_retile.py as the final option. I have added C:\ms4w\python\gdal to my pythonpath but within a pyscripter shell I can not import ...
