GDAL tool for convert color map to grayscale?
I need command line tool (I prefer from gdal tools) that convert color map to grayscale Several algorithms are possible – see Three algorithms for converting color to grayscale blog posting by John D....
View Articleconvert GTiff to AAIGrid results in cell size switch
I don’t have a clue why the conversion of a tif to an asc has that kind of behavior: original tif metadata Size is 466, 427 Coordinate System is: PROJCS["ETRS89_UTM_zone_32N", ... Origin =...
View ArticleGDAL, Georeferencing
I have been trying to use GDAL library to add geoinformation to an image. From the documentation from GDAL web page I could find that I could use GDAlSetGeotransform(), for that I need a six parameters...
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getting strange “grid” artifacts when creating hillshades using gdaldem
I’m trying to create hillshades from Czech elevation data (Fundamental Base of Geographic Data of the Czech Republic (ZABAGED®) – altimetry – grid 10×10 m) – a demo files is available here:...
View ArticleHow to Read&Write .tiff images in java using GDAL library
I searched many sites to learn about this but I didn’t find anything. I need step by step process for reading .tiff monochromatic image in java using Gdal library.
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Reprojecting from Lambert Conformal Conic into EPSG:3857?
I’m trying to reproject a plain png image file into EPSG:3857 for use in an OpenLayers application. I’m pulling the image from the NWS site at:...
View ArticleOgr2ogr trying to import and convert shapefile to EPSG:3857
I’m attempting to import a shapefile (along with .prj file) to MySQL using Ogr2ogr and using the t_srs option set to EPSG:3857 (the default for Leaflet and Google Maps) but I’m getting odd results, eg:...
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Can't import libraries to rsaga
I get this error when I’m trying to import a raster to RSAGA: > rsaga.import.gdal(paste(rast_name, ".tif", sep=""),"RASTER", env= my_env) Module 'GDAL: Import Raster' not found in SAGA library...
View ArticleArcMap: Unknown Spatial Reference fix with GDAL/Python
I have a .tif file that I created with Python and when I open it in ArcMap it says it doesn’t have spatial reference information. Is there a way to set the spatial reference with GDAL if I have a .prj...
View ArticlewriteOGR alters MultiPolygon holes
I’having trouble using writeOGR to write GeoJSON files, when there are MultiPolygon objects. Here is an example: I’m creating a SpatialPolygonsDataFrame object from GeoJSON, with a single feature made...
View ArticleCalculating NDVI with Rasterio
I’m using Rasterio to read GeoTIFF files from Landsat 8 and calculate NDVI into a new GeoTIFF file. My code looks like this: import numpy import rasterio import subprocess with...
View Articledissolve polygons of GeoJSON with gdal/ogr
I have a GeoJSON with only polygons in it. I have to dissolve (merge) the polygons with the same “DN”-value. I found out that you can do it with shapefiles like this: ogr2ogr outputfile.shp...
View Articleuse gdal python bindings from the QGIS folder in a custom script
I have QGIS installed (on Windows) and can import this line from the QGIS Python console: from osgeo import gdal When I try the import in a python file it doesn’t work Traceback (most recent call...
View Articlechange projection in an ascii (x,y,z) file
I am having an ASCII file (lat,long,depth) in the Mars projection. I need this file to be converted into WGS-84 projection. How can I do the conversion for the ASCII files.
View ArticleInterpolation using GDAL
I am looking for some hints here. There is a shape file with point data of rainfall sampled at a regular grid, and there is a shape file with point data of soil attributes sampled at a regular grip but...
View ArticleHow do I access GeoTransform array from gdal on the command line?
I’m using the gdal library via OSGeo for windows, and I was just wondering how to access the geotransform array for a .ecw file.
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Read HDF4 data using python
I am now working with VIIRS/NPP Active Fires by using python gdal. But I cannot read the data inside the files. Filename = “NPP_AVAF_L2.A2012019.0600.P1_03110.2014057125956.hdf” Here is some...
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read tiff to bmp in c# got only white image
i want to convert a tif image to bmp i was following tutorial in https://trac.osgeo.org/gdal/wiki/GdalOgrCsharpRaster but i dont get an image i want to see the code is : // Creating a Bitmap to store...
View Articleconnect gdal-java with tomcat
I am trying to run: SpatialReference poSourceSRS = new SpatialReference(); poSourceSRS.ImportFromEPSG(4326); String unit = poSourceSRS.GetAttrValue("UNIT"); System.out.println("unit: " + unit); on a...
View ArticleERROR 6: The PNG driver does not support update access to existing datasets
I was trying to overlay a shapefile to some raster images from a directory using gdal_rasterize. But then encountered this error ERROR 6: The PNG driver does not support update access to existing...
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