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

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Per-pixel 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
47 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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2answers
259 views

Stuck in loading raster to PostGIS

I am running running Mac OS X (10.7.5), PostgreSQL (9.2) and PostGIS (2.0.2) (installed via Postgres.app). The PostGIS extension seems to work perfectly with vector and raster layers. Once I enable ...
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1answer
50 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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1answer
100 views

How to extracting raster data to multiple polygons?

I have a reclassified raster dataset (10 classes) and I want to find out the area of each class contained within multiple (hundreds-to-thousands) polygons. I have all the polygons in the same ...
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2answers
836 views

How to export a PostGIS raster to PNG?

I have a raster which is split into 30 tiles and I want to dump them all into PNGs. I've read the documentation http://postgis.net/docs/RT_ST_AsPNG.html but still don't know how to dump it well. If ...
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1answer
60 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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3answers
105 views

How to use the GeoServer REST api to get a PNG representation of a layer?

Does anybody know if I can retrieve by REST service in GeoServer an raster representation of layer? Just like in for ex. ArcGIS REST Api: When I send: ...
2
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1answer
31 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
168 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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2answers
228 views

Can Geoserver return the raster value of a lat/lon point

I have a GeoTIFF published by Geoserver 2.2 and being used by Leaflet via WMS. How can I get Geoserver to return the raster value at a lat/long point? I'm guessing it has to do with using WCS, but ...
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2answers
85 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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26 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?
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2answers
48 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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1answer
18 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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1answer
43 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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1answer
37 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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82 views

converting vectors to raster (burning streams)

I converted my stream vector to a raster file (using polyline to raster conversion tool). I anticipated that I would get a No Data row in the raster file attribute table, so that I could use a ...
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3answers
932 views

How to publish ECW images to ArcGIS Server?

When I am going to publish mxd (containging image.ecw) to ArcGIS Server, the following error appears: Confiquration image.ecw. MapServer can not be started. Server Object instance creation ...
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3answers
1k views

NoData values recognised in raster in ArcGIS but not following symbology rules

I have a GeoTIFF raster in ArcGIS, which can be downloaded from the following two links: http://www.rtwilson.com/downloads/MODIS_MOD04_16-06-2006_Subset.tfw ...
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1answer
109 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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2answers
189 views

How to create a raster (topo to raster) with non-rectangular shape?

I'm using Arcmap 10, I need to create a raster from contour lines. These contour lines were clipped out with a certain shape with the purpose to modify them only within that shape and then create the ...
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52 views

How to convert a shapefile to binary grid?

I have a polygon shapefile with a UTM projection which I read into MATLAB: % available from http://sharesend.com/zhqsdc9x s = 'C:\path\to\shapefile.shp' % Read the shapefile shp = shaperead(s); ...
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20 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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3answers
433 views

Suggestions for an efficient way to store raster files for lab use?

I'm trying to create a repository for our raster files from various sources and Im exploring the possibilities on how to store them and deliver them in our local intranet. I have come across rasdaman ...
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1answer
379 views

Output of QGIS raster clipper not as expected?

My goal is to clip a raster with a polygon in QGIS 1.8. Based on an article I read, this should be a pretty straightforward task. However, the output appears to be empty. The raster produced is the ...
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1answer
29 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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29 views

IDW Interpolation Raster clipping

I used the CLIPPER tool under the 'Raster' menu to clip my interpolation raster with a polygon. the resulting output is not displaying anything even though the process completes without any errors. ...
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1answer
24 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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2answers
43 views

how to specify -t critical dowloading raster with raster2pgsql

I'm trying to download a raster into postgres/postgis. So far I wrote: raster2pgsql -s 3006 -I -C -M -R filename.tif -F -t 463.313x463.313 schema.rastername | psql -h localhost -U postgres -d db ...
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60 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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1answer
153 views

how to create an outline polygon (footprint) from raster data with postgis?

how can I create a polygon, containing the actual outlines (aka footprint) of a raster file with postgis? I just need the outlines of the data containing parts of the raster. ST_PixelAsPolygon ...
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22 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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1answer
99 views

Export ArcGIS Model to Python - Iterate Rasters, Collect Values, Calculate Values

I want to batch process a large number of raster files, calculate some values and properties and export these to a .csv or .xls. I managed to get a good working model that does this perfectly. ...
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34 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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1answer
61 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 ...
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19 views

What information, Open Attribute table of stream segment shows?

I have delineated the watershed from DEM data. I have converted the stream segment(raster) to vector lines. In the attribute table of this vector lines, there are 3 columns, CAT, VALUE, LABEL, what ...
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62 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
38 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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4answers
89 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 ...
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1answer
103 views

Scanned Transparent Map Overlay

We have a flat file of 50 Geology maps that have a transparent overlay with faults and drill holes. I have them scanned and georeferenced as TIF images and they will be used in ArcGIS 10.0, 10.1 and ...
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1answer
16 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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1answer
53 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 ...
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1answer
47 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 ...
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1answer
39 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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3answers
79 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 ...
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1answer
56 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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0answers
31 views

How do I select specific colors within a raster to create polygons with in QGIS or ArcMap?

We have a few georeferenced zoning map rasters and would like to convert specific zones (colors) to polygons, sometimes multiple zones as different polygons. Our workflow has been in the past to ...
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2answers
100 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
67 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 ...