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

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682 views

identify percentage of raster cells within a polygon

As per the title I want to determine the population inside multiple polygons according to different land use zoning (High Residential, Low Residential, National Parks etc) that's in raster format. ...
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244 views

Can't view PostGIS rasters after changing schemas

I have loaded a few rasters into the Public schema of a PostGIS 2.0 database. Using the db manager in QGIS 1.8.0 I can add the rasters to the map canvas. After moving the rasters to another schema in ...
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2answers
709 views

Can I prevent QGIS raster clipper from changing output cell/pixel size?

I have performed a DEM extraction using the clipper tool in QGIS 1.9.0 Master, using a mask layer, the original resolution of the DEM is 20x20 but in the resultant DEM the new resolution is 19.98x19....
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466 views

Qgis crash when I attempt to open ECW raster format.

I added Ubuntugis unstable repo and installed Qgis, libgdal-ecw-src, libecwj2-3.3 but still do not work. When I attempt to open an ecw file with Qgis it crash and tells me that there are problems ...
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669 views

Having issues removing white background from Raster images

I've got an issue with 4 raster layers that I have converted from kml files into layer files. It would only allow me to convert them if I used ground overlay and now the 4 raster images are ...
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230 views

Aggregating a raster to fit a polygon grid

I am working at the scale of 10 square km grid cells for the UK, and have a polygon layer of the Ordnance Survey 10k grid cells in ArcGIS. I have another layer of the human footprint index, also for ...
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312 views

What does “Computed -srcwin falls outside raster size” mean when clipping?

What does this mean, when I try to clip and save the result as a sqlite or other format please? "Computed -srcwin falls outside raster size of 7807x4771" cheers, Bruce
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327 views

How can I bring in grid files from Geographix into ArcGIS?

I have a set of grids of subsurface horizons, created from contours, that I have created in Geographix and am having trouble brining them into ArcGIS. Currently when I try to export the grid ...
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2answers
392 views

Some tiff not included on a vrt index

I have some tiff files and I'm trying to generate a vrt index with gdal tool, gdalbuildvrt. I run this command: gdalbuildvrt orto_index.vrt -srcnodata "0 0 0" -vrtnodata "0 0 0" *.tif and throws ...
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303 views

r raster package rasterize failing:no slots

I'm having trouble rasterizing a shapefile using the raster package in R. shp<-shapefile(ZoneShape); lcRas<-raster(lcRaster); r<-raster(ncol=ncol(lcRas), nrow=nrow(lcRas), crs=CRS); res(r)&...
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426 views

Layers and variables box does not exist in ArcGIS raster calculator window?

I have a problem with layers and variables box in raster calculator. The layers and variables box does not exist in the raster calculator window! So I cannot add any raster to the expression. I ...
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442 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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2answers
761 views

How to write raster field values into attribute table using ArcPy?

Is it possible to use ArcPy (10 or 10.1 )to write raster field types into a featureclass? either SDE or filegeodatabase?. I'm hoping to use arcpy as means of automating the process of adding rasters ...
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5answers
643 views

Create world file from kml

I have a KML file for a NASA image. I want to create a world file from it so I can use the image in say QGIS. Is it possible to extract the key info (bounding coordinates) from the KML? It seems to be ...
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1answer
1k views

How do I combine many ECW files in MapInfo?

I have MapInfo 11.5.0.16 (I don't have ArcGIS) and I am trying to combine (in some sense) a large collection of ECW files. I can load one ECW at a time in MapInfo but I have very many. MapInfo ...
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1answer
755 views

GetCapabilities Request for WMS

I'm trying to connect to a WebMapServer with the Geotools WMS classes. My problem is, that the resonse-object "capabilities" doesn't contain all layers. When I'm doing the request in a browser, I can ...
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405 views

Difference in raster size using raster2pgsql

I use the PostGIS-build-in raster2pgsql to load SAGA-raster into the db. I tried to grid them into 100x100-tiles, just as seen in the code: /usr/lib/postgresql/9.2/bin/raster2pgsql -s 32632 -a -F -...
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104 views

BIOMOD Error message: argument of length 0

I’m using the package BIOMOD in R to modelling habitat in rodent species. The data formatting works but I'm getting this error message when I run Modelling: ## Conputing the models ## ...
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1answer
234 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
767 views

What are Bands, Dimensions, and Histograms in QGIS?

First; I can see a band as synonymous with a channel in an image editing program like GIMP, is this correct? If so then bands play the role of color mixing and masking. Are there any other ...
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1answer
152 views

Problem loading raster to PostGIS using QGIS

I am having trouble loading a raster (.asc) file to PostGIS 2.0.1 using the plugin Database - PostGIS Raster - Load raster to postgis in QGIS 1.8.0 on Win Vista 64 bit. I get the following error ...
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277 views

Qgis - Raster clip Problem

I tried to use the Raster (Extration) tool "clipper" and I always get this error log: What is my problem? Fehler bei der Ausführung von Python-Code: Traceback (most recent call last): File "C:/...
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1answer
123 views

Sextante (SAGA) “Normalisation” problem

I don't understand the SAGA-module "NORMALISATION". In SAGA Gis I just can define one MIN and one MAX value. In QGis I have to define 2 of both. How to handle that exactly?
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2answers
271 views

Put color for raster data(aspect.tif) on QGIS1.8.0

I create aspect.tif from DEM file. I could put the values(0 to 360)from contrast enhancement. I could set color from color map(freakout or Pseudocolor). In here, the data is shown by only 4 colors. I ...
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382 views

How to add multiple rasters to a layer file?

I'm trying to make a .lyr file to bring into ArcMap with arcpy.mapping. I can bring a single raster into a .lyr with the script below. I'm unsure how to proceed to get multiple rasters from the same ...
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129 views

Set certain amount of pixels to 1 inside of a polygon (GRASS)

I have a rather coarse vector map with polygons and want to calculate a (sufficiently) finer raster map defined by spatial extension and resolution. Every polygon of the vector map has a value ...
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175 views

How to correlate raster map and elevation data?

I have been provided with a set of raster maps. Thanks to another helpful user here I have been able to acquire some elevation data for the same region from gis.utah.gov in asc format. Now I need to ...
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242 views

Why is transparancy of GRASS rasters missing when imported into QGIS?

I have a raster map in QGIS imported from a GRASS mapset with the QGIS GRASS plugin. The problem is that I have null() cells in the GRASS map that appear "colored" in QGIS. How can I set the ...
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1answer
81 views

How to conflate terrain data?

I have an 8 km by 8 km raster of 20 m/pixel terrain data. The georeference data has been lost. All I know is that it's within 100 km of Smithers, BC. I realize that this might involve some very heavy ...
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2k views

How to merge different classes/clusters in one single raster in arcgis 9.3?

I've created a signature file with 8 clusters and performed an unsupervised classification. Later I have grouped values (spatial) classes together to form 4 classes I needed (in symbology) but that ...
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185 views

gdal_rasterize -at function still won't capture covered pixels properly

I'm currently using the gdal_rasterize tool in bash. My code looks like this: gdal_rasterize -l $(basename $file .shp) -burn 1 -a_nodata 0 -te -180 -90 180 90 -tr 0.1 0.01 -at -ot Byte $file $OUTPUT/...
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2answers
273 views

Break between two raster layers (topographic maps)

I have the following problem [in QGIS]. In displaying two raster layers (topographic maps), a white area appears between the two. If I apply transparency to one of the layers, this white area still ...
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4answers
904 views

Determining gradient of road segment

I've a shapefile of roads data. It contains information about terrain of road segments, i.e., hilly, flat, undulating, etc. I want to determine gradient of every road segment. I know this might ...
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1answer
2k views

How do I add TIFF files to one layer/raster catalog?

We have several TIFF images (already tagged with position information) we want to load as a single layer into the map. It's the first time I dig into this raster/topology thing, but at least I managed ...
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410 views

Adding Field to Raster

Good day! I have a shapefile which contains X-specific field. I want to add this X-specific field (integer) to a raster dataset. I am using ArcGIS 10. How can I do this? Thanks.
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127 views

Can I avoid runtime raster interpolation by creating an image pyramid to match the zoom scales?

For image quality and performance reasons, it would be best to perform interpolation of my large TIFF image of the world (10GB) beforehand to all the zoom scales I need to display at so that MapGuide (...
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1answer
476 views

How to serve raster mosaic to AutoCad Map 3D from ArcGIS Server without its Image extension?

We are looking for a way to serve all the raster datasets we've collected over the years as a mosaic we have built in ArcGIS so that the AutoCAD department can simply import the mosaic and it will ...
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2answers
331 views

Configuring a WorldImage data store starting from a folder containing tif and tfw files

i have a folder of tif and tfw files and i'd like to show the raster in a map using geoserver. Even reading the geoserver tutorial for this kind of datastore (http://docs.geoserver.org/stable/en/user/...
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238 views

What are strengthes and flaws of using grid-cell analysis in GIS? [closed]

I'm going to use grid-cell analysis. What are the strengths and weaknesses?
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1answer
634 views

Preventing an Openlayers WMS layer from updating on zoom-change

I'm using openlayers to overlay a raster. When I zoom out, the overlaid layer expands to cover a larger area than was originally requested. I want the tile to be fixed to a particular boundary, and ...
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1answer
1k views

How to convert Geostatistical analyst (GA) file to Raster FAST?

I have been trying to convert a number of Geostatistical analyst files that i were created using Geostatistical wizard in ArcGIS 10. I want to save these files as Raster and use the File Am i ...
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3k views

How can I extract raster values around points?

I'm using ArcMap 10. I have a point dataset and a .flt raster. For each point I want the sum of the raster values that lie within a certain radius of each point. i.e. I want to extract values within a ...
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1answer
319 views

PostGIS Raster convolution filters

I've looked through the PostGIS raster documentation, but can't find an indication of how to apply a convolution filter to raster data. Does this capability even exist (yet?) There only appears to be ...
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575 views

OpenLayers ArcGIS Image Service Support

i have ArcGIS Image Server for publishing my raster data to my user. In traditionally way i have been tiling with gdal and it takes a long time besides this it requires more effort for getting true ...
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154 views

ESRI ISurface.GetElevation is extremely slow compared to GlobalMapper

I'm using ISurface.GetElevation on a Raster to get the elevation for a specific lat/lon. I have to do this for a huge set of datapoints. Currently i'm testing with a dataset of 10.000 items which ...
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1answer
137 views

Blank Vector Selection Dropdown in QGIS GRASS Plugin

I realise there are some issues which getting vectors into the GRASS module in QGIS, but is the behaviour i am getting expected? I have loaded the vector shapefile via GRASS, closed G and reopened ...
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1answer
308 views

How can GRASS export an .flt file?

I am using GRASS and connecting it to another application. The other application needs an FLT file of the raster map which I should export from GRASS. The other application only reads FLT files. Can ...
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147 views

Clip GAPAnalysis and save as a new file output strange looking colors

I download USGS GAP Analysis and use a polygon to clip raster from that GAP Analysis. I am wondering why there is a strange looking color when you clipped the raster. If you zoom in, you can see ...
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1answer
451 views

How to use r.patch with two maps having different colortables?

I am using r.patch to combine two raster maps in order to fill in the null values of the other. Is there a way to use r.patch but still maintaining the colortables of the separate raster maps? I do ...
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281 views

Creating color table file in PCI Geomatica

What is the simplest way to create a stand-alone color-table file in PCI Geomatica (PCT or STR)? I have some classified imagery with values ranging between 0-255 and I would like a way to ...