Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

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Add a raster specifying the projection in pyqgis

I would like add an raster but I want to specify the projection. If I do : qgis.utils.iface.addRasterLayer(url,layerName) QGIS ask me to specify the projection. I want to this with python. How I ...
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403 views

GIS beginner - interpolating contour lines from TIN-model vs. Grid in ArcGIS

I am a complete beginner in GIS and taking a class right now, and we are doing some assignments in ArcGIS - ArcMap. In one of them we were given a shapefile with heightpoints. These had been manually ...
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57 views

problem saving GRID to .img keeping original names (export by attributes)

I am really new in Python programming. I try to make a loop for Extract by Attributes tool in ArcGIS 10.1. I have a huge dataset of raster (760pc) and I want to extract a specific value. This part of ...
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1answer
208 views

Plot a Raster in R with white space for NA values

I want to produce a .png of a raster with background values plotted as white space. Below you can see the current state of the plot. As you can tell, the pixels which should contain NA values, ...
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198 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 ...
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292 views

References to code IDW algorithm

Hi I'm new to interpolations. I'm looking for documentation to understand how inverse distance algorithm works and how to code it. My intention is to code IDW algorithm in JavaScript to see if it is ...
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62 views

Define uphill side of roads and buildings

I have a big raster of a mountain region and I need to extract the uphill side of roads and buildings, from these elements to the pick of mountains. For a road I know the uphill side changes in ...
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1answer
399 views

R Raster package loop over pixels

I want to perform a trend analysis for each pixel over it's time dimension. Therefore I wrote a loop over each pixel doing the calculation but this is extremely slow. I am sure there must be a faster ...
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105 views

How to use USGS Bulk Download on EC2 linux Server?

I am interesting in downloading Landsat 8 rasters to an Amazon EC2 instance and would like to know how to do it. I already install USGS Bulk Download but I do not know how to use it in terminal mode ...
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61 views

write rasters from estudm2spixdf with significant digits

I have estimated my kernels using kernelUD from the adehabitatHS package which produces information from multiple animals as a class estUDm. I am trying to write out from R to get into ArcGIS the ...
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24 views

How do I randomly alter a raster with som correlation

I need to randomly alter an existing raster. The original raster is essentially a topography map that measures its values around a normal distribution ranging between 0.5 and 1.5 The new raster ...
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1answer
69 views

Cell Statistics in QGIS

Cell Statistics in ArcGIS will calculate the mean (or statistic of choice) among multiple rasters on a cell-by-call basis. Can QGIS do this? If so, how?
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785 views

Raster Multiplication - Can't Multiply Sequence by Non-Int of Type “Float”

I am trying to multiply a list of GRID raster datasets using a different value for each raster. The value is in the raster name. Some examples are [wse_1979_5,wse_1980_0,wse_1980_5], where 1979_5, ...
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243 views

Does QGIS support .sld style files for raster layers?

I'm currently looking at the documentation for geoserver, and I'm trying to load a raster and .sld file in QGIS to see if I can edit .sld files for raster layers. The .sld and raster are located here: ...
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2answers
69 views

Arcpy GetRasterProperties returns odd results

I have this simple piece of python code to test whether a raster has integer values or not: res = arcpy.GetRasterProperties_management(ws, 'VALUETYPE') res = res.getOutput(0) ...
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122 views

Convert raster_stats list output to array / csv file

I usually program in R, but recently I have started to use python for most of my spatial programming. My python skills are still limited, and please excuse the simplicity of the question. I am ...
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1answer
1k 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). ...
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1answer
241 views

Extract/Split raster dataset by attribute (OBJECTID)

I have a raster dataset with an attribute table generated from a series of image classification (unsupervised) and processing tools (majority filter + boundary clean). The attribute table shows pixels ...
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1answer
291 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 ...
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1answer
116 views

Why does a raster with resolution 5x5m not create a grid with these dimensions? [closed]

I created a 5m x 5m raster using ArcGIS 10.0 Spatial Analyst from a point file. As can be seen in the screenshots of the image and the table, the resulting grid has a higher resoluation than is ...
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2answers
204 views

How to show cell values of raster in ArcGIS

I would like to know if it is possible to display a raster cell value in the center of a cell with ArcGIS in the same way that SAGA-GIS does when you zoom in.
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99 views

Turn vector layer in raster layer based on cost

Hy, I am trying to rasterize some vector layers into raster layers and I know this is possible with QGIS by using the rasterize function in the raster menu but I don't know how to do the following ...
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85 views

Create custom raster pyramid using arcpy in ArcGIS 10.2

I have a arcpy script that runs the Point Density tool several times for the same extent, using the same number of neighborhood cells, but with cell size increasing at an multiple of 2 with each pass. ...
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1answer
79 views

GEOTIFF Binary File with Color Display Issues

I have a GEOTIFF in QGIS that shows values of 0 and 1 and I want the 0 values to have no fill so that background vector layers can show through and so I can easily overlay things in a print composer ...
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41 views

I want to reproject data from 0-360 to -180 - 180 [duplicate]

I've been downloading data from NOAA in a CRS that goes from 0-360. The rest of my data is in -180 to 180. What's the easiest way to reproject or shift the data in QGIS? It took 30 seconds in ArcMap, ...
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1answer
98 views

QGIS combine Vectorlayer and Rasterlayer to one shapefile

I have to create some Thematic Maps, especially Choropleth Maps on Matlab. Therefore i've found a shapefile which I can use, but need to draw some lines there. I've imported my shapefile as a Vector ...
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1k 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 ...
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1answer
156 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 ...
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1answer
664 views

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

ArcGIS Desktop 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 ...
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1answer
196 views

PostGIS: convert point data to raster

I have a table of points and I'm trying to visualize their distributions. Each point has a POINT geometry (WGS84) and some numeric attributes: a, b, c. | id | geom | a | b | c | ...
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283 views

Raster: mosaic first, or project first?

I have a thousand raster tiles in un-projected decimal degrees from which to build a seamless mosaic in a metres-based coordinate system. The final image will be about 70,000px by 50,000px. Which is ...
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461 views

How do I stop Kernel Density from cutting off symbology?

I need help configuring Kernel Density so that is does not cut off symbology on hot spots. (See pic below) I'm assuming it has something to do with the extent but I could not get it to display the way ...
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1answer
62 views

How to properly combine and export (as raster) vector lines on top of raster

I have a georeferenced TIFF with building plans on it. I then laid topo lines on top of it. it looks right in QGis. I now want to export this as an image (i.e. with the topo lines overlaid). How do I ...
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2answers
270 views

Handling hundreds of raster tiles in ArcGIS 10

I have 650 individual raster tiles (MrSID format) representing aerial imagery of a county. Each one is approx. 72 MB in size. As with a lot of aerial imagery, I use this as a base image for other ...
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1answer
45 views

Find Distance within each Raster contiguous cell block

I was asked to find for each Individual Contiguous Forest Block the distances INSIDE of each where it would be the farthest (aka the most isolated) from each forest cell block's respective edges. I ...
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Can I tell QGIS to load/show only a part of an image?

can I tell QGIS to load/show only a part of an image without to extract this region as an extra/ new image?
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1answer
116 views

Smooth out lines in QGIS

I have taken a raster image and coverted it to a vector file. It is an OS map which shows field boundaries etc. As the vector file has been created from the pixelated raster file the lines are ...
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3answers
342 views

Is there an iOS app to display several offline raster maps with transparency?

There are several iPhone apps displaying offline maps. Some of them can show custom maps, for instance loaded as MBTiles or sqlite files. Galileo-app does this pretty well. But it is only possible ...
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1answer
2k views

How to Calculate Area in Raster data in Arcgis 9.3

I run Supervised Classification on Spot image and now how to claculate The Area of different classes with out converting To shape file . because converting to polygon create too much polygon which is ...
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2answers
4k views

Convert MapInfo raster file (.tab) to use it in QGIS and/or ArcGIS

I am trying to convert raster files from MapInfo (.ecw, .jpg, .TAB) in order to use them with QGIS or ArcGIS. I have access to all 3 softwares. I have tried Data interoperability tools in ArcGIS but ...
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57 views

QGIS 2.01 - raster transparency not working properly

I have loaded a color raster image (aerial orthoimagery) into a QGIS project. The layer is visible but very transparent (in the enclosed image the vector polygons are below the imagery), but when I ...
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2answers
108 views

How to get information about only one data point?

I have a vector-point shapefile. The data are not dense (about 1 x 1 degree). Lets say that every point includes value of average wind speed. I would like to create a interactive web-map so that ...
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3answers
1k views

Creating DSM and DTM from a LAS using a freeware solution

Is it possible to export a surface and terrain model files from an aerial, LiDAR point cloud (LAS) set? I am using SAGA GIS for very basic operations, but I couldn't find this option (and I have a ...
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2answers
118 views

Copy Jp2000 from Mosiac Dataset turns white

I am trying to copy a raster to jp2000 from another File Geodatabase that I created as a Mosaic Dataset. It came out as a whiteout in the middle. I don't know what it cause this. See screenshot : ...
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1answer
106 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 ...
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1answer
59 views

How can I assign Raster2 pixel value to Raster1 where they overlay?

I want to assign Raster2 pixel value to Raster1(Bigger) where they overlay. Both of them have the same cell size. How can I accomplish this process in ArcGIS Desktop? (Like Raster Calculator ) ...
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1answer
187 views

Calculation amount or number of certain pixel-values in a raster

It seems pretty simple but until now I could not find a proper solution: In a given raster i want to know the number or ratio of e.g. red pixels. Edit: to be more precise: I have a number a arial ...
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78 views

Is there any GRASS command to measure the distance between a point in rastermap and another in vector map?

I have a question about WinGRASS 6.4.3. Is there any GRASS script command to measure the distance between a point in rastermap and another in vector map? I have a raster map and a vector map. Raster ...
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2answers
58 views

Polygon Data to Fit Raster

I'm working with an NHD Flowline of streams and rivers in NC, and I'm trying to only retain the ones in the raster. I tried to convert to the raster to a polygon and was going to clip them, but in the ...
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2answers
538 views

Polygon shapefile to Raster with Mask and Extent

I have a polygon shapefile (Vesijärvi lake). The lake has many islands, bays and inlets. When I look at the attribute table, there are actually two adjacent features: Northern lake and southern lake. ...