NumPy is an extension to the Python programming language, adding support for large, multi-dimensional arrays and matrices, along with a large library of high-level mathematical functions to operate on these arrays.

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13
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5k views

Writing numpy array to raster file

I'm new to GIS, and I'm lost with something I feel ought to be relatively simple. I have some code that converts infrared images of Mars into thermal inertia maps, which are then stored as 2D numpy ...
13
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1answer
917 views

How can I utilize NumPy arrays to optimize big data geoprocessing?

I'm interested in learning how to utilize NumPy arrays to optimize geoprocessing. Much of my work involves "big data", where geoprocessing often takes days to accomplish certain tasks. Needless to ...
11
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3answers
536 views

How to convert LAS file to numpy array?

I have begun learning how to manipulate LAS data in python and wanted to see how others handle LAS files. I would like to read the points (I am using a numpy array), and filter out classes 1 and 2 ...
10
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3answers
2k 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, ...
8
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3answers
5k views

How to fully load a raster into a numpy array?

I have been trying to check my filters on DEM raster for pattern recognition and it is always resulting in missing last rows and columns(like..20). I have tried with PIL library, image load. Then with ...
7
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2answers
1k views

How to keep spatial reference using arcpy.RasterToNumPyArray?

I am using ArcGIS 10.1, and want to create a new raster based on two preexisting rasters. The RasterToNumPyArray has a good example which I want to adapt. import arcpy import numpy myArray = ...
7
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1answer
238 views

Why is matplotlib installed with ArcGIS?

Today I upgraded to ArcGIS Desktop 10.2.2 as well as the 64-bit background processing tool and noticed that both numpy and matplotlib were installed with Python. In fact, in the "What's New?" section ...
6
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1answer
726 views

Subsetting GeoTIFF with Python

I'm sub-setting a GeoTIFF with the GDAL Python binding and numpy. Essentially, I am providing a central location (coordinates of a flux tower) from which I produce a subsetted image. I then want to ...
6
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1answer
485 views

ArcGIS Desktop 10.1 SP1: how to install/use additional Python modules?

I'm currently working on a project where I have to identify geomorphological features in a digital elevation model. Since the aim is to have a single ArcGIS Toolbox integrating all processing steps in ...
5
votes
2answers
477 views

Adding noise to a raster

I want to add some fine-grained noise to a raster in an automated python process (i.e. I do not want to use Photoshop or GIMP). I looked at PIL, but unless I'm mistaken, it doesn't seem to have any ...
5
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2answers
360 views

Creating numpy.array with variable number of fields to test arcpy.da.ExtendTable performance?

There was an ArcPy Café blog posting entitled Adding Fields: Performance Tips which advocated: Two approaches to help increase performance when adding numerous fields to a table or feature ...
5
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1answer
103 views

PySAL natural breaks from Numpy array

I am attempting to extract natural break values from a raster using Python. The intended process goes: Arcpy raster object to NumPy Array (using RasterToNumPyArray) to natural break values (using ...
5
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2answers
705 views

Does anyone use both ArcGIS and Python(x,y)?

I'm trying to get ArcGIS 10.1 and Python(x,y) to peacefully co-exist with a unified installation of Python. Surely someone else is using both these tools... right? Pointers would be much appreciated. ...
5
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0answers
217 views

Save fails on raster object created from NumpyArrayToRaster [closed]

I am trying to save an ESRI grid built from a numpy array and am getting an error I've never seen before: Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly ...
4
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2answers
629 views

Obtain coordinates and corresponding pixel values from GeoTiff using python gdal and save them as numpy array

How to obtain projected coordinates as well as the actual pixel values at those coordinates from GeoTiff file and then save them into a numpy array? I have arsenci020l.tif file, and its coordinates ...
4
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1answer
316 views

XYZ Clustering in Python and numpy arrays

I am looking for a method of clustering XYZ data in Python that works on numpy arrays. I know of a few sources, such as clusterpy and Pysal but have had little success with them as they seem to still ...
4
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1answer
552 views

raster algebra in python with rasters of different extents

I am trying to find out how to use GDAL & numpy modules to average a set of rasters....which are Sigma0 values from satellite passes at different times within a year. Each raster has been ...
3
votes
1answer
434 views

How to change value of an individual pixel using arcpy?

I want to change the value of an individual pixel in a raster using arcpy. The code I wrote for changing the value is below, but it changes all of pixels in my raster. How can I set an individual ...
3
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2answers
194 views

Downloading raster data into python from postgis using psycopg2

I have raster data in a postgres table that I want to get into python as a numpy array. I am using psycopg2 to connect to the db. I am able to download the data but it comes back as a string (probably ...
3
votes
2answers
214 views

Memory and Processing Efficient Approach to Read a Timeseries in Python

I am trying to store a timeseries of high resolution raster images containing NDVI values into a dictionary for calculations. I am curious as to which approach may the most efficient when loading ...
3
votes
1answer
1k views

Iterating through an numpy array and index to a value in another numpy array

I am struggling to get this code to work I want to iterate through an numpy array and based on the result, index to a value in another numpy array and then save that in a new position based on that ...
3
votes
2answers
227 views

How to publish GP Service with importing of numpy in ArcGIS for Server 10.1?

I use a lot of scripts as GP Service almost all use the arcpy functions but one (and very important) of my scripts needs a gdal/ogr and numpy imports. I can run this script in PyScripter or as a tool ...
3
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1answer
351 views

Selecting raster values at random locations in a raster in python/arcgis

I have a large dataset of integer rasters, and was hoping to find a way to generate a "random" selection of pixels for four of the rasters, while making sure all 5 classes, which I've specified based ...
3
votes
2answers
587 views

PostGIS + pgRouting: Adding dummy links to a road network and performing routing analysis

I'm a beginner when it comes to postgis and pgrouting development. For a project I'm working on and a bit of the algorithm: I have a polygon layer that represents zones I have a line layer that ...
3
votes
0answers
116 views

Tabulate Area using GDAL and Numpy

How could I perform a Tabulate Area using GDAL and Numpy? I am trying to summarize how many pixels of each class in a Landcover raster are within each polygon of a Census Blocks shapefile. I've ...
3
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0answers
308 views

Buffering a Raster with GDAL and Numpy

I am using GDAL to convert a raster dataset into a numpy.array and then using numpy to buffer the data in the raster. For example, I need to know all the regions within 100ft of a school point ...
2
votes
1answer
489 views

Calculating beta-diversity w raster data [renamed]

Using ArcGIS 10, it is not possible to generate a raster attribute table for 32-bit float values. Instead, I have tried the RasterToNumPyArray method, which crashes since the file input raster is so ...
2
votes
2answers
172 views

How to calculate monthly maximum values from daily data in a 365 band grd?

I have a MINT2005.grd file which has 365 bands representing days of year from 2005. Each band is a 32x35 matrix representing the temperature at different latitude and longitude pair. How do I ...
2
votes
1answer
41 views

Replicating result of gdalwarp using gdal Python bindings

I am trying to re-project/resample with the GDAL python bindings, but am getting slightly different results compared to those from the command line utility gdalwarp. See update below for shorter ...
2
votes
1answer
86 views

arcpy array: trouble with reassigning inf to 0

I've converted rasters to arrays via arcpy.RasterToNumPyArray() then divided them by 1. Some resulting values are zero and I need to reassign them after the division to zero. The array types are ...
2
votes
1answer
132 views

Loading features attributes into numpy array

I am currently working on an add-on that relies on the user choosing fields of tables (that can be from shapefiles, csv or dbf) that are open in QGIS and then making computations with such data. ...
2
votes
0answers
126 views

How to get QGIS to play with pandas (Windows)?

has anybody been successful getting pandas to work with QGIS's Python installation, on Windows? I've used the OSGeo4W installer to install QGIS2.2, which comes with Python 2.7 and Numpy 1.5.1. Any ...
2
votes
0answers
308 views

Finding coordinates from a nested grid as a numpy array

So this is a pretty basic question, but I'm trying to figure it out. I've written a script that allows a user to read in a raster and provide a cell resolution, and outputs the amount of cells ...
2
votes
0answers
302 views

How do I use scipy.ndimage.gaussian_filter1d on an arbitrary axis?

I have a GDAL raster that looks like this: And I would really like to blur this raster along an arbitrary transect. I see that scipy.ndimage has a gaussian filter that allows me to blur the raster ...
1
vote
3answers
1k views

Is it possible to open rasters as array in NumPy without using another library?

I know that it is possible to open a raster as an array in NumPy using GDAL, but I want to skip GDAL and use NumPy only, as it is cooler handling rasters with NumPy as matrices. There is a similar ...
1
vote
1answer
443 views

Installing pandas with Esri's python?

Trying to get pandas to import, but I'm getting what looks like an error caused by a failed dependency of the version of my Esri-provided numpy's compile, based on this stackoverflow posting. Here's ...
1
vote
1answer
187 views

Problem with calculating the total cell values

aa= arcpy.RasterToNumPyArray("water_depth") sum = numpy.sum(aa) print sum -2933737 Why I am getting negative values ? In my raster there is no any negative ...
1
vote
2answers
896 views

Error "unsupported operand type(s) for +: 'int' and 'NoneType' for variance in python

I recently came up with an error in a script I am working with in Python for ArcGIS 10.1. The strange thing about it is that this script works for some files and not for others. Any ideas as to why ...
1
vote
1answer
129 views

keeping the coordinate system of raster files in the resulting raster file after operation with numpy

I'm trying to read as array two raster files using ReadAsArray in GDAL/python, perform some map algebra operation on it using numpy and then write the resulting raster file in GTiff format using ...
1
vote
1answer
123 views

errors after installing 64 bit background geoprocessing on ArcGIS desktop 10.2.2

I installed 64 bit background geoprocessing on my ArcGIS 10.2.2 and then changed my pythonpath to "C:\Python27\ArcGISx6410.2" so that my code can benefit from the 64bit. then I had to install a 64b ...
1
vote
1answer
293 views

Raster calculation in for loop returning exit code -1

I've put together a python script that does some calculations on rasters by converting them to NumPy arrays, doing the math, then converting them back to Raster and applying all the same spatial ...
1
vote
1answer
43 views

Trouble importing NumPy in GRASS. Architecture

I can't get GRASS to work on my system, and after doing some digging I think it is related to me using 64-bit python. I'm not really sure. I get this message... This module requires the ...
1
vote
1answer
50 views

Multiply raster by Numpy derived float value

So I have a python script that uses numpy to calculate the mean of a field, then I try to use that mean value in a raster multiplication as follows: na = ...
1
vote
1answer
131 views

Migrating data from Python to PostGIS

I have pandas DataFrame with these columns: point datetime value 1 Point(-24.6064453125 26.3683280945) 2014-09-11 19:00:00 24.885258 2 ...
1
vote
1answer
239 views

Convert WKT (or geojson) geometry to numpy array of coordinates

I am looking for the fastest way to convert WKT or geojson geometry from string to numpy array of coordinates. Is it possible to do it strictly in Python and without creating geometry object such ...
1
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0answers
20 views

Raster Vector stack

I want clipped image of NDVI for a particular area. I did raster calculation for getting the image with NDVI values. After that I tried extraction function clipper. In this function we have to use two ...
1
vote
1answer
52 views

Wrong coordinates after Usage of NumPyArrayToRaster(…)

My Project I am currently working at should enable cellvalue manipulation on raster files using ArcPy. My Script works fine except I am not getting the right Y-Values (northing values) for the ...
1
vote
1answer
94 views

gdal_proximity distance to meters

I followed the answer given in this topic for searching the distance to the nearest coastline given a lat/lon coordinate. The distance output obtained is in degree (I think) but I need the distance ...
1
vote
1answer
620 views

Convert polygons in shape file to a numpy array?

I have a shape file containing a number of polygons and all attributes being text. I'm trying to import the polygons into numpy as an array where each polygon is represented as unique values. I ...
1
vote
0answers
125 views

Efficient computation of path profile with Numpy and GDAL

I have numpy array with SRTM elevation data and I need calculate path profiles - vectors with elevation data from one point (transmitter) to every points of my map. Here's my current solution: def ...