NumPy is a Python module, 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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15 views

How to use gdal_calc.py for multi-band images?

My problem is that I have multi-band images (8 bands) in GEOTIFF format and I tried to use gdal_calc.py to calculate a conditional expression between those bands. However, I could not make it because ...
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1answer
277 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 ...
4
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1answer
211 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 ...
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0answers
25 views

Calculate exact percentile for each rastercell and create new raster with percentile values [on hold]

I need to calculate the exact percentile value of each raster cell in a raster layer, in order to create a new raster layer with this exact (decimal) percentiles. (In excel this function would be "...
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0answers
37 views

Classifying data as Natural Breaks using ArcPy?

Is there any chance I can create a simple python script to classify my data as Natural Breaks? I have only created a script for quantile classification, but it is not enough for my work. arrp = ...
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1answer
485 views

Convert Raster to Numpy Array with only Arcpy and Numpy

All the articles I'm finding including GDAL or PIL(?) which I cannot use. So I am trying to convert a raster I have to a Numpy Array with Arcpy and Numpy and then calculate some statistics on it but ...
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626 views

How does gdal_calc numpy operators work?

Gdal_calc manual Gdal_calc is introduced as : gdal_calc.py - Command line raster calculator with numpy syntax gdal_calc.py [-A <filename>] [--A_band] [-B...-Z filename] [other_options] OPTIONS:...
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0answers
21 views

How to create raster layer directly from numpy array in QGIS, without saving to file?

I have managed to create a numpy array from a raster file using commands from the gdal library, and now I would like to load that raster as a layer without saving it first. It seems like there should ...
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0answers
22 views

Scanning a raster by moving windows. Output rasters off by a cell. ArcGIS, python

I'm working in extracting smaller rasters from a bigger one (yellow). I'm using only python, some numpy maybe. I succesfully extracted a patch from a big raster, secuentially, by moving windows. So I ...
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1answer
30 views

Numpy raster reclassify outputs only 2 out of 6 classes

I have a raster (.tif) which I want to classify (6 classes) using gdal, python and numpy. The cell values range from: MIN = -30.9847 to MAX = 7.3505. From the first two answers in this question, I've ...
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1answer
45 views

Extracting small numpy array from a bigger raster, by moving windows. Memory issues. ArcGIS

I'm trying to extract a small raster from a bigger one, just using python and numpy (I'm not allow to use any other software). This code just reads a from a big raster, extracts an smaller window, ...
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1answer
55 views

NumPy to GeoTiff for use with Gdal

I have a few NumPy arrays: lat, lon, and 6 data bands. I'd like to convert these to GeoTiff and then apply the gdalwarp function, based on a specific projection, to each band. Is there a standard way ...
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0answers
145 views

Accelerating python looping process for A-star path finding on DEM surface?

I try to make an A-star Path Finding program base on tile-graph (image raster data as graph) where each pixel values represent as cost and elevation.. In my case, DEM raster data was called by using ...
5
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2answers
207 views

Optimizing Python GDAL ReadAsArray

I am using the GDAL ReadAsArray method to work with raster data using numpy (specifically reclassification). As my rasters are large, I process the arrays in blocks, iterating though each block and ...
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0answers
35 views

I can't import arcpy to python in arcgis. What do I do?

I'm running ArcGIS 10.3 on Windows 10. I get an error message when I try to import arcpy. I'll include the error message that I print screened. Should I just un-install ArcGIS and reinstall it? or ...
2
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0answers
33 views

QGIS segmentation fault related to numpy on Ubuntu

I'm running QGIS 2.14 on Ubuntu 14.04 and everything's been working just fine until I upgraded a few Python packages via pip this afternoon. Since doing that, QGIS crashes with a segmentation fault ...
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0answers
20 views

Why can't get correct RGB img of Landsat 8 using np.dstack

I use np.dstack to stack Band4, Band3, and Band2 of Landsat8 data to get ture color image,I use code from Milos Miljkovic, but the result looks incorrect. import numpy as np from matplotlib import ...
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1answer
40 views

Statistical properties of raster image

I want to calculate mean and standard deviation of a raster image. In QGIS zonal statistics, we can calculate it within a polygon or a vector. But I want to calculate for whole image. In Python I'm ...
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1answer
62 views

Calculating distances with SciPy and subsequently join identifiers

I have lots of start points and a handful of destination points. Using 'Point Distance' from the toolbox takes ages to calculate and write the results. Hence, I was looking for alternatives and went ...
2
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1answer
21 views

Numpy TypeError when turning ndarray into structured array [closed]

I want to turn my ndarray(670911L, 39L) into a structured array using a view: c = arr.view(dtype=[(n, ‘float64’) for n in names]).reshape(len(arr)) where names is a list of 39 strings. But I am ...
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0answers
27 views

Create Diference TIFF image from two TIFFs

I am trying to use gdal_calc to calculate the differences between two almost identical images. The problem is that the images are tiffs with three bands (RGB) and the result is difficult to interpret. ...
2
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1answer
40 views

How to get value of uvIndex for a particular latitude and longitude from a grib2 file?

I'm trying to find out the uvIndex of a particular set of lat,lng. I'm getting the data file from this link. I'm using pygrib to read the file. import pygrib grbs = pygrib.open('uv.t12z.grbf01.grib2'...
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1answer
94 views

numpy.unique: ValueError: all the input arrays must have same number of dimensions

I'm trying to get the unique values of an array but am getting an error that doesn't make any sense. Here is my pseudo code: import numpy as np import gdal # I have a .tif file, call it inputRaster:...
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4answers
602 views

Raster reclassify using python, gdal and numpy

I would like to reclassify a raster file from a raster with 10 classes to a raster with 8 classes using pyhton, gdal and/or numpy. The classes are represented as integers. I have tried following the ...
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0answers
98 views

GDAL RasterIO performance in C++ vs ReadAsArray in python/numpy

I'm currently writing optimisations for a raster viewer program which uses gdal as it's base. It's currently written purely in python, and has some major speed issues which cause problems when we are ...
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0answers
30 views

How to get 4 values for different Indexes and names of rasters for set of points? [closed]

I am trying to get 4 values for different Indexes and names of rasters for set of points, but get problem with defining function def extractIndex(raster, pathName). #List of Folders 4 Folders ...
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1answer
96 views

NumPy Array to Feature Class: NameError from Inner Loop Variables

I have a NumPy Array to FC script that parses a JSON web-service. The outer loop writes to my FC correctly, however my inner loop variables come back as not defined when appending the items. The ...
3
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1answer
120 views

Memory error in python when reclassifying array

I have a .tif that I read into an array (call it tifArray), and I would like to classify the array based on set of conditions: Where 1200 <= tifArray <= 4000, outputArray = 1 Where tifArray &...
5
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1answer
75 views

Getting pixel values at single point using rasterio

To get a single pixel value at a point in a raster using rasterio, there is an example here: https://github.com/mapbox/rasterio/pull/275 However, is there a direct API within rasterio (and not the ...
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0answers
43 views

Arcpy cannot find shapefile attribute [closed]

I want arcpy to perform the following: load a shapefile, prepare to edit it, open its attribute table, perform a numpy.digitize using the values of a certain attribute and some bins provided ...
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0answers
56 views

Create raster with decibel value from Geotiff Intensity using QGIS GDAL python

I have raster with intensity values and I want to create raster with decibel values, I work with QGIS GDAL, I use gdal_calc I do this from the terminal: gdal_calc.py -A input_image.tif --calc="10*...
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0answers
169 views

Python with ArcGIS: import scikit-learn fails (bad numpy.dtype)

I am trying to install scikit-learn 0.17.1 (current) into my Python 2.7.3 that accompanies my ArcGIS 10.2. The installation through easy_install goes through smoothly, but I get the following error on ...
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1answer
1k views

How to place an numpy array into GeoTIFF image using python-gdal

I am attempting to export data of varying scales into GeoTIFF images...a new method for me. The problem I'm running into is when using the GDT_Byte pixel type, data values < 0 and > 256 are not ...
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0answers
38 views

Possible to resample tifs in numpy array? [closed]

I need to resample a large number of tif files. Is it possible to put the list of rasters in a numpy array and resample the array? I'm thinking this would be faster than looping through the list, but ...
1
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1answer
116 views

Modify 3D numpy array using interpolation

I have a 3D array that I want to interpolate the np.nan values along the z dimension, and I just want the changes to modify my existing array. However, the changes seems not to be working. I have a ...
5
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2answers
1k views

Installing both ArcGIS for Desktop and Python(x,y) on same machine?

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? Here's where I've gotten to: ...
9
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1answer
254 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 ...
3
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0answers
89 views

Select shape file by their coordinates behavior [closed]

I want to filter shapefiles by their latitude behaviour: If the latitudes of edges A and B are constantly decreasing or increasing then this class marked as correct, otherwise are incorrect. For ...
5
votes
2answers
370 views

What's the most efficient way to load feature attributes into a 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
1answer
351 views

Plotting “large” image with points with matplotlib - MemoryError

I want to plot an image of 3193 x 3293 pixels with 1502 points. When running in a smaller image and less points (934,722 pixels and 60 points), everything runs perfectly. I wrote like this: # I am ...
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0answers
133 views

Write stacks of GeoTIFF image to NetCDF by chunk size

I converted GeoTIFF image stacks to NetCDF file with writing data by Index order (layer by layer) (this was a main solution). The problem is, it writes slowly (for 25 images - 1Gb takes 90 seconds). ...
0
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0answers
28 views

Using numpy.dstack() for merging two 3D arrays but losing spatial reference.

The code is as following: >>> temp = numpy.dstack((spi_negative,spi_positive)) >>> >>> temp.shape (16, 126, 294) >>> out_ras = arcpy.NumPyArrayToRaster(temp,pnt,...
1
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1answer
97 views

Anaconda and ArcGIS 10.1

I am having problems installing Anaconda with ArcGIS 10.1. My problem is specifically with pandas. ArcGIS python is my default python version. I installed python 0.16.2 in this version, which ...
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2answers
59 views

applying equation on numpy array [closed]

I have a 3d array: >>> print arr_u_num [[[ nan -3.90149352 -1.21931281 -1.08366785] [ nan -2.07270503 -1.27621887 -0.89320389] [ nan -2.69618795 -1.98927089 -1....
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1answer
65 views

how to save a raster after converted from numpy array?

I'm trying to save a raster after calculation in numpy array. Here is what I wrote: rasterSM = arcpy.NumPyArrayToRaster(SM, lowerLeft, cellSize, value_to_nodata=nodata) rasterSM2 = arcpy....
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2answers
41 views

Trying to maintain spatial reference on newly created numpy array

I am trying to copy the values from raster into newly created array and then trying to save the array with same spatial reference as raster file inRas = arcpy.GetParameterAsText(0) double_layer = ...
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0answers
46 views

return _NumPyArrayToRaster(*args, **kwargs) ValueError

I am trying to make an array to raster from the defined array below. However, I keep getting this error: return _NumPyArrayToRaster(*args, **kwargs)ValueError: Argument in_array: A two or three ...
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0answers
129 views

TypeError: unsupported operand type(s) for *: 'numpy.ndarray' and 'numpy.ndarray'

I am trying to insert a value for different group of percentile eg (0- 10 percentitle) value = 1. I saw an example over here and went to try it out How do I Calculate Grouped Percentiles or Batch ...
4
votes
2answers
382 views

Reconstructing MODIS time-series applying Savitzky-Golay Filter with Python/Numpy

I want to apply the 'Savitzky-Golay' (savgol) filter to my time series, MODIS dataset, to remove noise (i.e., cloud pixels, etc.) in my data. MODIS have quality flags that indicates the reliability of ...
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1answer
11k views

Avoiding ImportError: No module named numpy?

When I try to import numpy, I get the following message. >>> import numpy Runtime error Traceback (most recent call last): File "<string>", line 1, in <module> File "c:\...