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Questions tagged [numpy]

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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Count number of pixels from .msk in Python to derive study area size

Apologies I am totally new to GIS in Python. I am trying to find out the total area of the Barents Sea mask the NSIDC use to calculate their products and therefore I need to know how many pixels the ...
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11 views

Reducing run time to extract cell values from multiband rasters? [migrated]

I have the following function and code snippet to extract cell values for multiple years, format it, and save to a list. Each raster has 365 bands -- one for each day. A separate operation is ...
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44 views

OpenCV Remap image from rectified image coordinates

I have orthorectified a drone image using ground control points. This results in a (4096 x 2160) array of recified X coordinates and a (4096 x 2160) array of Y coordinates. I want to remap the ...
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17 views

ArcGIS is importing orginal numpy while VirtualEnv is activated

I could activate ArcGIS's python command windows to use VirtualEnv by "execute execfile(r'C:\Users\jason\myenv\Scripts\activate_this.py', {'file': r'C:\Users\jason\myenv\Scripts\activate_this.py'})" ...
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24 views

PyQGIS Creating Numpy Array from QByteArray (QgsRasterBlock.data()) and vice versa (QGIS3) [closed]

I am looking for a way to convert the values contained in a QgsRasterLayer object to a numpy array and vice versa without using any GDAL methods. To obtain the numpy array I go through ...
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23 views

Compare Specific Points of Line Features in two Feature Classes using FeatureClassToNumPyArray

I am looking to compare the first and last point between features in two different feature classes. The features share a common ID. My thought was to create two arrays via FeatureClassToNumPyArray. ...
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29 views

Writing numpy arrays to irregularly shaped, multiband raster

I have the following numpy arrays: predictions; type is float32; shape: (94, 1461) lats; float32; shape: (94,); centroid of cell in vector layer, decimal degs. lons; float32; shape: (94,); centroid ...
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40 views

pyinstaller stops in the middle of process

I try to create a .exe from a .py script. I use Pyinstaller. The script runs fine with no errors in Pycharm. If I open the .exe my Tkinter opens I can choose the files etc.. And then in the middle of ...
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11 views

GDAL rastercalc giving unexpected results

I have a raster file containing the following values: data values from 0 to 8488 nodata values values equalling -3.40282347e+38 The values equalling -3.40282347e+38 are presumably supposed to be ...
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1answer
54 views

Open 4d NetCDF subdatasets with GDAL in Python

I have NetCDF files containing subdatasets with 4 dimensions: time, height, latitude, longitude. Here is an example of the output of GDAL GetSubDatasets(): ('NETCDF:"Martinique_ALT22.nc":height', '[...
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111 views

“No module named numpy” Python Error in ArcGIS Label Expression?

I have developed code to label points that pull formatting from a dictionary. I developed this code and it was working fine two weeks ago, today I try to open my map and I am now met with an error ...
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52 views

Broadcast Shapely Point on numpy array

I have some code that looks something like this: def get_objs(all_objs, line, my_distance): """ Gets all objs within my_distance of line. all_objs is a numpy array of shape (x, 4) ...
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24 views

Calculating Raster Percentile Values in ModelBuilder

I want to calculate the 75th percentile value of a raster dataset (floating, 32Bit) and use this value as an input to a set null expression. I have multiple rasters to perform this on so I need to ...
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1answer
67 views

NumPyArrayToFeatureClass gives RuntimeError: create table

I've tried to change polygon feautre to point by using tools: FeatureClassToNumPyArray NumPyArrayToFeatureClass. My code as below: import arcpy import numpy as np in_file='C:/ios/...
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1answer
47 views

Extracting values from array created with FeatureClassToNumPyArray and converted to DataFrame?

I cannot understand how to use the values in the arrays created with arcpy.FeaturesToNumPyArray. I want to create an array and then convert them to a pandas DataFrame. So I created an array from ...
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1answer
64 views

Array in python just full of zeros when opened using GDAL

I'm working on the below script. What I'm trying to do is create a stats.txt file output which has the Land Cover Class ID, Fractional Coverage (of that class) and the number of pixels (of that class) ...
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1answer
51 views

Classifying quantiles in raster dataset with ArcPy?

I am trying to write a Python script which uses the reclassify function in ArcPy to create 9 classes in a raster file. I want to use the quantile method to create the breaks, but so far, I can't seem ...
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122 views

Binary Raster (numpy array) to shapefile

i did a classification with a min/max threshold for stormdamaged areas. For that i calculated two indices (NSDVI) and (SAVI). I intersected two numpy arrays from those results. I recieve a binary ...
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56 views

Fill masked array values with reflect padding

I have a square matrix (image) with masked values in an area. The mask corresponds to missing values in areas close to the border (always). I want to create a new image where the masked values are ...
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1answer
166 views

How to create a GeoDataFrame points grid from a numpy.mgrid?

I'm trying to create a GeoDataFrame points grid from a numpy.mgrid. I already have created the numpy.mgrid with coordinates of future points. >>>arr = np.mgrid[-1827342.1753285176:-1827523....
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2answers
41 views

If field 1 > field 2 update field 3 in loop

I am trying to update the table above. What I want to do is if the values in the PMP fields are less than the Max fields update the check fields with PASS, if not FAIL. I started doing this trying ...
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1answer
142 views

NumPy array to Raster file (GeoTIFF)

I converted a raster file (one band grey scale) to an numpy array and set a range to it. I Did like that: import gdal import numpy ds = gdal.Open('H:/GDAL_docs/a.tif') myarray = numpy.array(ds....
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1answer
63 views

Get data from a raster using two coordinate arrays with Python

I'm trying to find a function in Python, that given two arrays with geographic coordinates, returns a list or array of raster values in those positions. that is to say: import numpy as np """geog ...
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1answer
69 views

Loading all rasters in a directory and naming the variables iteratively

Hi I'm working with prism data and I already have clipped (masked) rasters (*.bil files) of a specific area for each day of a year. I'd like to open all these rasters with rasterio, convert them into ...
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1answer
160 views

Comparing pixel values at a given point in two rasters

I have two raster images, one for land use and one for NDVI, i would like to calculate LAI based on land use. So i need to compare the pixel value in the NDVI raster and Land use raster then select ...
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59 views

Numpy import error in OSGeo4W Shell

I and my colleagues are running into a very frustrating Python import error while using the OSGeo4W Shell. Any time we attempt to use gdal_calc in a Python script, we get the following error message: ...
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1answer
151 views

Using rasterio and matplotlib how can I create a window for an NDVI image to fit into?

I am using Rasterio, Numpy, and Matplotlib. I created a window with the dimensions of 800x600 and plotted the band 5 for a Landsat 8 image, that worked just fine. I also have the nir image so then I ...
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1answer
206 views

Using Rasterio, Matplotlib, and Numpy trying to calculate and plot NDVI of a raster image getting error: IndexError: list index out of range?

First I create two variables and store my raster images in them and I use MatPlotLib to plot a subset of the original "nirband" raster image. That works fine. I am getting an IndexError: list index ...
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0answers
43 views

Using Null Values in Raster To NumPy?

I am trying a convert a raster dataset [a simple 4 x 4] into a numpy array using RasterToNumPyArray. Here is my sample raster dataset: RasterToNumPyArray however, returns zero for Null values: ...
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84 views

QGIS 3 - Save processing output to memory and turn into numpy array?

I'm currently developing a python plugin for QGIS 3. In short, the code conducts among others a viewshed algorithm, turns the output in a numpy array and calculates some spatial metrics the user can ...
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1answer
119 views

How to convert masks generated by rasterio to channel last mask

The problem is about using rasterio to generate mask from GeoJSON file which contains geographic coordinates. The function that I used is from: from rasterio.tools.mask import mask with rasterio....
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391 views

Writing numpy array to rasterio raster file generates empty file

I'm using Rasterio to read GeoTIFF from Sentinel 2 and calculating NDVI, but when I try to save as a new TIF file, the file turns to transparent and empty file. What am I missing? That's the code: ...
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112 views

numpy array coordinates to polyline in shapefile Python

I am calculating the shortest path in a numpy array which was converted from a raster (.tif). I have a list representing a path like [(1,3),(2,3)(3,3)]. How can I transform this into a polyline in ...
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1answer
120 views

Write array to CSV inside arc script tool (works in pycharm, doesn't work in arc)

I have an arcpy script in which I am writing an array to a CSV (for later use in the script to make a routeing layer). I've tried a couple iterations, and all work like a charm in PyCharm (can't ...
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0answers
235 views

Networkx shortest paths for two point layers

I have a task to know the best way from houses to subway station. There are three types of data on a picture below: orange dots are the entrances to subway stations violet dots are centerspoints of ...
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84 views

Point displacement between map (Cesium 3D) and raster (numpy array)

It is better to show than tell: On this image, the layer below the colorful shape is a trivial heat map in raster format. The colorful shape is the product of the skimage.graph.MCP_Geometric method. ...
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1answer
232 views

Writing a raster file from multi-dimension array using Python

I've been attempting to create a raster file that has multiple bands (10 or more) from a numpy array with multiple dimension(i.e. 10 or more). The script I'm currently using exports the TIFF file I ...
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1answer
210 views

Determine size of GeoTIFF header

Is there a way to find the size (in bytes) of the header information in a GeoTIFF file using Python? I am not trying to read the header (I know I can use gdalinfo for this) but rather to figure out ...
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1answer
627 views

Efficiently read large tif raster to a numpy array with GDAL?

I have been using the Python GDAL API to read tif raster files as NumPy arrays. Previously, I simply read the raster into an array directly with GDAL: ds = gdal.Open('example.tif') fullarray = np....
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1answer
229 views

Numpy array to raster with ArcPy [closed]

I have a Python script to download data in netCFD format. I have managed to extract the information I need in a masked array. This looks like: print(my_array.shape()) >> (700, 299, 217) As a ...
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360 views

Opening numpy array to rasterio?

I have numpy array that I know bbox for and can transform like this: import rasterio.plot from rasterio.transform import from_bounds t = from_bounds(minx, miny, maxx, maxy, sorted_np[3,:,:,7].shape[...
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0answers
28 views

Google Earth Engine Output - Returns Unexpected Values with np.sum()

I am exporting a CHIRPS precipitation raster from Google Earth Engine. This is part of a larger collection of data that I'll be exporting, but I'm just inspecting one image at the moment. I've ...
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2answers
580 views

NumPy memory error on large rasters

I have multiple large rasters. Their 5 percentile and 95 percentile are needed to be calculated. After loading the rasters to the ArcMap, I am using the following codes - import numpy import arcpy ...
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1answer
57 views

Raster representation in arcpy/numpy

I have a .tif raster file which contains integer values at 1, 2, 3, 4 and 5. Importing this file into ArcMap also shows a number of cells with Nodata value where the above classes are not present. I ...
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2answers
611 views

How to create a TIFF file using GDAL from a numpy array and specifying NoData value

I have some tiff files I obtained from splitting a bigger tiff file using gdal translate. The border tiff files have some nodata values, which I can see in numpy as number 15. I want to manipulate ...
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0answers
1k views

GDAL 2.3.1 is installed but the llinux terminal is using GDAL 2.2.2

I asked this question before realising this site existed: https://stackoverflow.com/questions/51476826/gdal-2-3-1-is-installed-but-the-llinux-terminal-is-using-gdal-2-2-2 I've installed GDAL 2.3.1 ...
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1answer
144 views

NumPyArrayToTable() RuntimeError: The value type is incompatible with the field type. [id]

# Create a dataframe from sorted JSON dictionary containing desired data df = pd.DataFrame(data, columns=['lat', 'lon', 'id']) # coerce dtype 'O' object values to np array native float64 type df['id']...
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1answer
652 views

Use Google Earth Engine to read MODIS NDVI into python

I'm trying to adapt this example for my needs: https://mygeoblog.com/2017/10/06/from-gee-to-numpy-to-geotiff/ The difference is that I'm using the MODIS NDVI image collection. # define the image img ...
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1answer
886 views

How to split multiband image into image tiles using Rasterio?

I have been using this answer on GIS SE to split 3-band (RGB) imagery into 256x256 3-band image tiles: import os, gdal in_path = '/path/to/indata/' input_filename = 'dtm_5.tif' out_path = '/path/to/...
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1answer
211 views

ArcGIS region group open source equivalent in numpy/python?

I am trying to get a unique ID for contiguous raster objects with the same value, like what the Region Group tool from ArcGIS does. However I need an open source solution using python/numpy/gdal/...