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

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3k 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). ...
2
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1answer
572 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 ...
6
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1answer
470 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
149 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
799 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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141 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 ...
2
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0answers
150 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
124 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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49 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
125 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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3answers
2k 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
194 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 ...
6
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1answer
2k 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 ...
5
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1answer
480 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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2answers
473 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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1answer
1k 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 ...
2
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1answer
100 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 ...
2
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2answers
529 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
65 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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0answers
33 views

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?
2
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1answer
171 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
621 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
5k 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
8k 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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0answers
75 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
127 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
2k 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
119 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 : ...
0
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1answer
153 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
77 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 ) Don'...
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1answer
310 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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137 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
76 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
923 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. ...
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1answer
662 views

Extracting data from a raster to a polyline based on start and end points?

I have a polyline shapefile with the attributes seen above. startx and starty represent the coordinates of the beginning of each segment of a polyline. endx and endy represent the coordinates of the ...
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1answer
355 views

How to perform a standard deviation stretch on a raster in QGIS

Is there a way to perform a (2) standard deviations stretch on a raster image in QGIS 2.2? I have found the raster styles menu, but the help says there is no help in my language (English) and whilst ...
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1answer
55 views

Is rid=2 significant in PostGIS raster structure?

It seems that in most, if not all, examples with raster appear to include the WHERE rid=2 statement in the query. http://postgis.net/docs/RT_ST_Value.html Is there something about the rast structure ...
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4answers
574 views

Best tutorials on raster data formats and raster manipulation [closed]

I am looking to improve my understanding of raster formats and how to manipulate them. I don´t really want to go into the mathematics of it, but really want to know the differences between the ...
3
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1answer
347 views

Combining Geological Grids and extruding between them?

I have a situation where I have 3 Geological grids, each showing a different horizon + the Seabed Grid. I need to extrude between these grids in order to make the 3D polygon for the geological ...
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2answers
630 views

QGIS Quickly switching overlapping raster images

I'm new to QGIS, and haven't used arcGIS in about 5 years, however I've just seen someone using arcGIS and was able to quickly switch between overlapping rasters when checking registration. The top ...
2
votes
1answer
511 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
359 views

Merging Raster: ImportError: No module named _gdal_array

When I try to merge rasters I got following error message: _gdal_array = swig_import_helper() File "C:\PROGRA~1\QGISDU~1\apps\Python27\lib\site-packages\osgeo\gdal_array.py", line 18, in ...
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1answer
746 views

Floating point calculations in QGIS

How do I manage floating point calculations in QGIS? I have carried out 3 consecutive calculations on landsat bands. I end up with 32 bit floating point rasters on which I can't carry out a 4th ...
2
votes
3answers
468 views

How to reclassify only a part of a raster but keep the rest unchanged (ArcGIS or R)

I'm trying to reclassify only a certain part of a raster...not the entire raster. Here's the problem. I have a LULC raster of the entire US. There are some issues with the raster that I want to fix,...
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1answer
80 views

What format to store/use four band Raster data

I have four band aerial photography - RGBI. I need to share it with my users, a mixture of MapInfo, QGIS, and ArcGIS. What format should I store/serve the data in? GeoTIFF isn't well suited to four ...
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2answers
2k views

Why am I getting 'Error 000732 Raster does not exist'?

I am trying to apply symbology to a raster layer via kernel density analysis. When I run the Python script below in ArcMap, I am get the error message below. I have searched and tried the common ...
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1answer
497 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 ...
3
votes
2answers
3k views

How do I open images georeferenced in ArcMap in QGIS? (.aux.xml)

We have several ArcMap georeferenced images (raster datasets) that we are attempting to open in QGIS without any luck. These are not inside of a geodatabase and are not Arcinfo Binary Grid format or ...
2
votes
0answers
214 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
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0answers
161 views

How to compute surface of raster or any point using ARCGIS?

I have a raster image whose values are a digital elevation model of terrain. I need to know the surface type (topographic characterization) of particular points along transects of this DEM. How to ...