2
votes
1answer
29 views

Is this a known issue in gaps between masked raster and spatial polygon in R with mask command?

This is my codes raster file: RAD polygon(shape): ws_sfc RAD.sub <- crop(RAD, extent(ws_sfc)) plot(RAD.sub) RAD.sub <- mask(RAD.sub, ws_sfc) plot(RAD.sub) plot(ws_sfc, add = TRUE) ...
0
votes
1answer
23 views

removing spurious lines in raster before or after vector conversion?

I'm looking for a feature/function in either python opencv/ndimage/gdal/etc. or qgis/saga/grass that will help clean up a skeletonized image that I'd like to vectorize into a shapefile of ...
0
votes
2answers
25 views

Aggregating rasters with GDAL

I have a set of files that have been mosaiced into a global VRT in a particular projection and resolution. However, I have a need to report statistics on a (say) one degree grid, where the reported ...
1
vote
0answers
30 views

GDAL WMS in QGIS 2.4

I'm trying to add in QGIS a layer shown here : propluvia When I watch in my console I see this request corresponding to the layer I need. The server is not able to respond to a getCapabilities ...
2
votes
0answers
33 views

Error in polygonising raster data with QGIS on Mac

I'm using QGis Chugiak on a Mac and I'm trying to converting a raster layer in a vector data by: Raster/Conversion/Polygonize. So, I select the layer needed from the drop-down menu, I give a name to ...
3
votes
2answers
54 views

GDAL (Python) Aggregate Raster Into Lower Resolution

I have a (continent-scale) raster with 30m resolution in an Albers equal area projection. Each 30m cell has a value 1-34. I would like to aggregate information from this raster into a 1km grid such ...
1
vote
2answers
35 views

Is there any efficient way to create a raster with pixel value representing a unique id calculated based on pixel lat/lon?

I have 10m raster for each state in US. Current pixel value represents something. I want to have 'same' raster but pixel size representing a unique id calculated based on pixel lat and lon. I am ...
2
votes
0answers
36 views

(How) can I write string data to a raster with Python/GDAL?

In Python, I have a NumPy array of string values (categories of some variable) that I'd like to write to a raster file (.tif or .img) using GDAL. The impression I get is that it's not possible to ...
2
votes
1answer
27 views

Error reading large virtual raster with rasterio: “Cannot invert degenerate transform”

I've created a virtual raster using gdalbuildvrt, which covers a large extent (England) at a high resolution. The data is fairly sparse, focused around the coastlines with no files covering inland ...
1
vote
1answer
59 views

how to use gdal_rasterize? how to know which attribute to burn with ogrinfo?

I have a vector layer I need to rasterize. I guess this is a basic operation, but I haven't found the information I need yet. First, I have reprojected the vector shapefile: ogr2ogr -s_srs ...
0
votes
0answers
31 views

Merge/mosaic categorical rasters in QGIS/GDAL

I am attempting to make yearly bins of some monthly MODIS data for all of the US. The cells of the raster are defined with Julian dates indicating the date at which a burn event took place. After ...
2
votes
3answers
54 views

Use GDAL command line to copy projections

I have two images, a georeferenced Tiff and a second Tiff without a reference. The second image is a copy of the first, but it lost its reference. Now, I want to copy the reference from the first Tiff ...
0
votes
2answers
65 views

gdal2Tiles output differs from MapTiler

I'm in need to process a large batch of Landsat images with MapTiler and since the version I'm using (1.0 Beta 2) does not support multiple input files, I created a simple python script that calls ...
0
votes
0answers
35 views

Polygonize only pixel values of 1 from a raster

I have a raster mask that I have created in QGIS (2.2.0) that consist of 0, 1 and nodata values. I would like to end up with a polygon dataset that consist of only the value of one pixels from this ...
3
votes
1answer
60 views

Projection mismatch when plotting precipitation with ggplot

I'm trying to plot accumulated precipitation in Brazil for a given period, see code below: Load packages library(raincpc) library(SDMTools) library(raster) library(ggplot2) library(rgdal) ...
0
votes
0answers
38 views

Combine overlapping rasters in gdal_calc.py, taking the maximum value from each pixel?

I want to combine 3 overlapping rasters to create 1 raster. Each have the same dimensions, resolution and CRS. I want to populate the new raster with the maximum value from each of the layers. ...
0
votes
1answer
23 views

gdal_rasterize : getting area not in or touching polygon (options -at and -i)

I would like to capture the area that is not in a polygon (option -i) and that doesn't touch that polygon. gdal_rasterize -at will return the polygon + edges, but gdal_rasterize -at -i will not ...
4
votes
1answer
83 views

Why the result of a merge of multiple raster is so big?

I try to merge 14 geotiff like this : Each geotiff is about 50Mb. I need a geotiff at the output My workflow : gdalbuildvrt -input_file_list list.txt test.vrt (where my list contains the name ...
0
votes
1answer
29 views

QGIS processing does not support jpg

I would like to work with the gdal functions provided in the processing toolbox. It is easy to call: import processing processing.alglist() ...
1
vote
0answers
45 views

How do I convert a .bil (and associated .clr, .blw, .hdr, and .stx) files into georeferenced rasters in R? OR to geotiffs using gdal_translate?

The title says it all. I've got a bunch of .bil files, which I can open in R using the raster command pointed to the path to the .bil file. But I don't know how to efficiently incorporate the ...
3
votes
2answers
73 views

“Levelling” elevation data coinciding with polygon?

I have a shapefile containing building geometries (polygons) and a elevation dataset. The elevation data doesn't perfectly match the buildings. I want to "flatten" the elevation data so that ...
1
vote
1answer
98 views

Rasterizing polyline data with QGIS/GDAL: custom line width

I need to make a raster from a polyline shapefile. However, when I use gdal_rasterize (either directly or through QGIS), all my lines are drawn one pixel wide, while I need them to be drawn with the ...
0
votes
2answers
67 views

From RGB raster to grayscale

I have been searching for a way to rasterize shp files (Unexpected output when using gdal_rasterize) and it worked with a little help. Now, my code is first rasterizing the largest sip file and than ...
1
vote
1answer
65 views

Unexpected output when using gdal_rasterize

Ok, I used the following code for converting my layer into raster format but I get a tif file that is completely black or white... from osgeo import gdal, ogr # Define pixel_size and NoData value ...
0
votes
3answers
54 views

Colorizing raster in QGIS 2.2 without using OSGeo4W command line?

Total beginner in QGIS. Following this guide right now: https://www.e-education.psu.edu/geog585/node/695 At step 4 I created the simple txt file which I now need to use to colorize the raster ...
3
votes
3answers
75 views

QGIS Mosaicing with null values in images

I have a set of landuse landcover data which needs to be mosaiced. Whenever i try using QGIS Raster>miscellenous>merge tool. giving no datavalue as '0', it returns either (A) ' Traceback (most ...
1
vote
0answers
78 views

Problem with polygon overlay in raster stats using gdal

I am using the raster_stats module in python to calculate the mean carbon value for different sets of polygons. Here is the code that I am using: africa_sat = ...
0
votes
2answers
311 views

using Python to calculate NDVI, output as a Geotiff

I need a script that can calculate NDVI from two separate input Geotiff files, then output the results as a Geotiff. I wrote following script, most of which is borrowed from various on-line sources ...
3
votes
1answer
237 views

Re-project raster image from Mercator to Equirectangular

I have a raster image of the world map in Mercator projection, square 1:1 format. I want transform the image into an Equirectangular projection accurately. I assumed from my research that GDAL would ...
0
votes
0answers
86 views

Make a raster with pixel scale 100 by 100 meter with gdal_rasterize

I'm asking here, because, I've got great results last time. Here it is the next of my adventure with gdal_rasterize, I want to make a raster picture where each pixel correspond to a square of 100 by ...
1
vote
2answers
183 views

Conversion of point grid to a raster with open source tools (Gdal, QGIS …)

I'm looking to do something which seem simple to me, but I haven't found a solution since 2 days I looked for. I've got a Postgis DB with lot of points (WGS84) spaced of 100 meters which cover a ...
0
votes
1answer
109 views

Gdal creating raster rotated wrong way

I have been trying to read in a stack of images for a timeseries and created an output raster that contains the max pixel values of the timeseries. The arrays were created using numpy img_stack = ...
1
vote
1answer
200 views

QGIS DEM (Terrain models) Mode Slope creates wrong data [duplicate]

I have a DEM raster file downloaded from the USGS site. The file can be downloaded here. I am trying to create a slope raster in percent with the DEM tool in QGIS. The GDAL command is the following: ...
4
votes
2answers
135 views

Converting shapefile to raster: Character attributes

I've got a shapefile that I would like to convert into a raster, but the trick is that the attribute I want a raster version of is character data. I'm familiar with geoprocessing using GDAL (in the ...
1
vote
3answers
350 views

Topography: How to get the x,y,z coordinates of highest or lowest point/pixel of a raster GIS?

Given a .tiff topographic raster image with mountains and deep sea, I am looking for the x,y,z specifics of the highest or lowest point. The x,y,z values being: altitude (z-coordinate) latitude ...
2
votes
2answers
96 views

Gdal: highest and lowest point/pixel, how to get their altitudes?

Given a .tiff topographic raster image. How to get the altitudes of the highest and lowest point/pixel ?
1
vote
2answers
146 views

Mask image based on no-data pixels in another image with different projection - GDAL or Python

I've got a land cover image which covers the whole globe, and a satellite image which covers a very small part of the globe. These two images have different projections, co-ordinate systems and pixel ...
1
vote
0answers
134 views

Workflow with raster in Qgis 2.2

I'm trying to build a workflow with the Qgis 2.2 processing toolbox. I want to clip a raster layer with a vector layer using the GDAL tool "clip with a layer mask". But it doesn't work. The error ...
2
votes
1answer
376 views

Georeferencing an image with GDAL, based on QGIS Georeferencer Plugin

I would like to georeference an image with GDAL. The image already has a spatial reference set (EPSG:31276). For the georeferencing, I have a list of 4 ground control points (also in EPSG:31276). ...
6
votes
1answer
153 views

GDAL equivalent of ArcGIS Mosaic

The word 'mosaic' is often used for quite different things within the worlds of ArcGIS and GDAL. With GDAL and it's downstream applications like Qgis it is common to see mosaic used in the context ...
3
votes
2answers
225 views

Per-pixel (statistical) calculations on a raster stack using GDAL

In R, it's relatively trivial to perform per pixel calculations based on a raster stack (e.g., get std.dev for each pixel on a 12 layer GeoTIFF). Unfortunately, the speed is less than desirable when ...
0
votes
1answer
89 views

gdal's polygonize function (via qgis) is not turning monochrome rasters into readable shapefiles regardless of inversion of color scale

I've tried polygonizing this monochrome bitmap as this: and this: and either way it ends up looking like this when (zoomed in) after gdal's polygonize operation: Is there any way I can tell ...
3
votes
1answer
213 views

ArcGIS Raster Mosaic Dataset and GDAL VRT, when to use?

ArcGIS has a the Raster Mosaic Dataset, QGIS and friends have Virtual Raster Tables. A skim of the documentation reveals much similarity. They both create or enable an alternate representation of ...
0
votes
1answer
63 views

Cannot display Oracle raster images using QGis

I am dealing with QGIS 2.2 and the plug-in Oracle spatial georaster. Apparently the connection to the database can be made, as the raster images are listed once you press 'Connect', but when try to ...
0
votes
1answer
88 views

Convert a KML ImageOverlay to World Files with GDAL

I have many raster outputs from an Open Source radio transmission topographic path tool called SPLAT, georeferenced in KML image overlay format. I have figured out an easy way to use tools to ...
0
votes
1answer
150 views

Create Tiles for a raster(georeferenced) to use in leaflet

I have raster, with each pixel containing some data. What i want is to split a large image with each pixel's color is determined by its value, to show on leaflet layer.How to go about this ? raster ...
1
vote
0answers
65 views

Extra row and column in a raster after GDAL grid import

I'm exporting an ESRI grid to TIFF format and after that I'm reading this exported raster file into SAGA GIS. However when Saga reads this file in there appears to be an additional row and column in ...
3
votes
3answers
147 views

how to digitize areas of a raster and snap to the raster cells?

I need to digitize the extent of an ecw raster image where the RGB value is not black.(see attatchment)ie. not the envelope, just the area where the image is shown without the border areas. The black ...
1
vote
1answer
573 views

Clip raster layer with *raster* mask layer in QGIS

Given two input layers 1. The clip layer - an arbitrary layer (though in my case it's a float 1 band geotiff) 2. The mask layer - a paletted raster in which every pixel is either NO DATA or a single ...
0
votes
0answers
60 views

Update a NetCDF file using GDAL

I have to edit a NetCDF file using GDAL in C++ code. When I try to update a subset I have this error message: ERROR 6: The NETCDF driver does not support update access to existing datasets. How can ...