# Tagged Questions

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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### 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 "...
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 ...
21 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 ...
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 ...
44 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, ...
36 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 = ...
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 ...
32 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 ...
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 ...
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 ...
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 ...
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 ...
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. ...
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 ...
39 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'...
95 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 ...
118 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 &...
93 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:...
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 ...
73 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 ...
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 ...
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*...
164 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 ...
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 ...
115 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 ...
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 ...
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). ...
27 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,...
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### 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 ...
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....
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....
40 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 = ...
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 ...
128 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 ...
377 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 ...
204 views

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 ...
44 views

### Read latitude/longitude to create new point grid at higher resolution

New to SE, needed to reformat my other question. Basically I'm looking at reading a CSV with longitude and latitude points (in this case housing exposure, simplified below): HUC4,Longitude,Latitude ...
32 views

### More pythonic approach to resolution increase of point locations

Excuse my first question being slightly more Numpy and less actual GIS, but it relates to latitude / longitude so I thought I'd give it a shot. Problem: I have a flat file with latitude and ...
113 views

### Numpy error when computing scores based on percentiles

I want to calculate scores in one field based on the percentile (in steps of 10) the row falls into in another field. I found a solution here (Calculating Percentiles in ArcMap?) that I tried out, ...
72 views

### Determining proportion of raster cells containing each value from list for many rasters in raster stack?

I wrote a function to determine the proportion of raster pixels that contain each of a list of values that I would be interested in. I then wrote a function to apply the previous function to a 3d ...
481 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 ...
193 views

### Total count of values at each pixel in a raster stack/ 3d array

If you have an array with x, y and z dimensions, how can I create an array of x, y dimensions that holds a count of how many z values at each location (x,y) are noData? I would prefer to use numpy ...
1k views

### Reading, modifying and writing a geotiff with GDAL in python

I'm trying the learn the ropes of Remote Sensing image processing using Python GDAL bindings and numpy. As a first attempt, I'm reading a Landsat8 geotiff file, do a simple manipulation and write the ...
421 views

### Reclassify a raster value to -9999 and set it to the nodata value using python and or gdal

I modified a script which reclassifies a raster. It is based on the script by Roger in his blog (the second script) and it works pretty well.The problem I am facing is as follows: I would like to ...
203 views

### stack raster using GDAL and numpy dstack

I am testing Savitzky-Golay filter with my MODIS dataset. Currently I am testing for 10 rasters (but later on will use my whole dataset) only just to test how should I create my script. So my initial ...
599 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 ...
179 views

### NumPy is missing, but fixing the environment variable removed my printer settings?

I recently installed regular Python on my workstation in addition to ArcGIS 10.2. Based on various things I found online, it seemed like the consensus was to install the full Python, because there are ...
114 views

### How to calculate the raster statistics with polygon layer using numpy and scipy in python?

I have used zonal statistics from processing to calculate the raster statastics with polygon layer. processing.runalg('qgis:zonalstatistics', rlayersource, 1, vlayer, None, True, Path) But this is ...