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

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3answers
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Reproduce raster with same extent, and same number of columns and rows?

I have two raster A and B. A and B have the same grid size but different extent. How can I make A have the same number of columns and rows, as well as the spatial extent of B?
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1answer
149 views

How can I create an animation with raster data in qgis?

I have 4 raster images showing different coniditions of air flow distribution at different times. I'd like to create an animation to show the change from image 1 to image 4. How can I do this? I tried ...
1
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1answer
748 views

ArcMap 10.1 - Tabulate Area tool “doubling up” for Overlapping Buffer Zones

This question is related to a previous question I asked: Raster Version of Spatial Join (one to many) I used the Tabulate Area tool to crosstabulate values between an overlapping "buffrast" raster ...
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1answer
26 views

Output Raster r.cost.full values

I am having troubles interpretating the output of r.cost.full. Currently i am working on a project comparing some arcgis tools with qgis tools (workflow and output). One of my examples is to make a ...
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0answers
33 views

Why does @data@values slot for RasterLayer only contain logical(0) and not the actual values?

Trying to get to the bottom of why, when I read in a raster of NDVI, the @data@values slot does not contain the actual values until I set them manually. For example: NDVI <- ...
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8answers
19k views

Get boundary of raster image as polygon in ArcGIS Desktop?

I have a rectangular raster image in ArcGIS. My question is: how can I produce a polygon which is just the extent of the raster image? That is, I want to have a polygon layer with a single ...
4
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1answer
170 views

How to stack rasters for ecological analysis?

The attached image shows two different forest openings. Each opening has the following layers associated with it: Point shapefile 1 = A red X which represent a large "legacy" tree in the gap Point ...
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1answer
598 views

Managing sizes of input rasters for raster calculation in ArcGIS Desktop?

To calculate any formula (conditional statements/relational operation etc) in the raster calculator in ArcGIS using two different sources of raster images, I'd like to know input rasters must be the ...
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0answers
45 views

Reduce population density grid from 10km to 1km [on hold]

I've a 10km cattle density grid, the units are head/sq. km. I would like to convert the grid to 1km and maintain the units.
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1answer
23 views

Workflow for updating raster using polygons of different attributes

I require a specific output but it is proving difficult for me to work out a workflow. I have: 1) polygons of new housing developments (356, non overlapping) 2) a 25m raster of land cover I want ...
0
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1answer
31 views

Properly placing my raster over a shapefile on my map

I have an ASCII file that I converted to a raster. My heading on the ASCII file is: NCOLS 156 NROWS 720 XLLCORNER -170989.3011812 m YLLCORNER 1417628.464462 m CELLSIZE 1 ...
0
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1answer
330 views

How to build an attribute table in a 3-band raster?

I have a 3-band (RGB) raster file from CORINE and the attribute table hasn't been built. When I try to execute the command BuildRasterAttributeTable I get an error that only single band rasters are ...
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0answers
31 views

Raster (Tiff) to KML for Google Earth Overlay - QGIS

I am trying to convert some raster files to KML in QGIS for overlay in Google Earth. They are really huge Tiff files as I processed them from 3 meter DEM datasets. I have been searching the web and ...
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0answers
26 views

Zonal Statistics for multiple rasters

I'm trying to create a timeseries of raster data (one layer per year) by polygon (Administrative regions). Is there any way in QGIS to perform Zonal Statistics for multiple years (without having to ...
2
votes
1answer
22 views

Mosaic rasterstacks based on minimum of certain layer?

I am trying to mosaic 42 remote sensing rasterstacks (with 250 bands) based on the criterion that in overlapping areas, the pixel should be taken that has the most nadir viewing angle Beside my ...
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2answers
19 views

Unable to set raster surface resolution in ArcScene?

I have a 3-band subset of a Landsat image which I want to display in ArcScene (of ArcGIS version 10.2.1). The image is 30 meter resolution and I am draping it on a 25m resolution Aster DEM. But have ...
3
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1answer
707 views

Why is Orthorectify button not active in Image Analysis Windows in ArcGIS10?

I wanted to Ortho rectify GeoEye HR imagery using existing RPC and IFSAR DTM in Image Analysis. According to ArcGIS Resource center ...
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0answers
26 views

Draw gridded lines inside a feature and generate random points

I have several vectors containing features that originated from a 30 x 30 m raster. I want to generate a grid of lines (fishnet) in all of the features that are more than 30 x 30m. As shown in the ...
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2answers
40 views

ArcGIS 10.3 Build Raster Attribute Table fails for large rasters

I am looking at forest loss in Central and South America within protected and unprotected areas. So I have a binary raster (0 or 1) for forest in 2000 and another raster for forest in 2013. I want to ...
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4answers
88 views

Unable to read raster into R: 'TIFFReadDirectory:Failed to read directory at offset'

I'm getting a weird error when trying to read a raster into R. >r <- raster('myraster.tif') Error in .local(.Object, ...) : TIFFReadDirectory:Failed to read directory at offset 2606110 ...
0
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1answer
29 views

Combining multiple overlapping rasters - retain maximum value?

I have 40 overlapping raster grids (derived from flood modelling software) that I want to combine in such a way so as to retain only the maximum value in any of the given rasters at each grid ...
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2answers
40 views

It's possible to use gdal_calc.py with an entire path of rasters?

I try to use gdal_calc.py to scale and transform a time-series of MODIS images. I've done that when i worked with a single image in the -A variable and a mask in -B, but i need to work with a ...
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1answer
477 views

Building attribute table from raster in ArcMap 10.1

I have a NetCDF file containing the latitude, longitude and porosity for the entire US. I am trying to add another value (wilting point) which depends on the porosity. I wanted to extract the netcdf ...
0
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1answer
56 views

Combine several rasters in QGIS

I have a problem combining several rasters into one big raster. Particular annoying is, that I had this problem once before and solved it, but I can't remember how. Unfortunately the other ...
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0answers
17 views

Selecting all pixels above a given value in a raster in PostGIS

I have a raster with one band whose value represents the date of the occurrence (a sequential integer). This raster file gets updated regularly, and each time that happens, I need to run a process ...
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1answer
34 views

How to clip a raster by extent using Processing from the Python console?

I want to clip a raster by extent in QGIS with the python console. Here is the description given in the documentation. You have to use the following input parameter: Input layer Nodata value ...
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1answer
196 views

Topo To Raster executing but not creating the raster

I am using Topo to Raster by File (ArcGIS version 10.1) via arcpy on a large stream and point dataset. Arcpy runs fine and executes without issuing any error message, however it does not create the ...
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1answer
161 views

error invalid output extend in zonal statistic

i have a problem with arcmap10.2...i have a dtm(that now has dimension of the pixel 1000) and another raster whit the same resolution with the code of a specific area..what i want to do is calculate ...
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0answers
26 views

'combine' more than 20 raster bands

I have overlapping polygon data that I would like to 'combine' in ArcGIS and I'm running up against the 20 band maximum for rasters. I'm interested in solutions using this basic method with Arc or ...
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0answers
24 views

Merging DEM files using PostGIS

I have several DEM files and I want to merge them to create a mosaic. I found the St_Union(raster) or St_MemUnion(raster) functions but I don't know how to use them. Are there any other solutions?
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votes
3answers
465 views

Raster map in different zone () than region ()

I am new to QGIS (just installed QGIS 2.0.1) and am having problems running any spatial analysis tools. I followed the instructions on how to call GRASS tools into QGIS, but when I try to run the ...
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1answer
55 views

Clipping a tiff image using another tiff image using python

I am working on a code to clip a raster with another raster. I have a forestcover.tiff image and i want to clip it by using other image clip.tiff which extend lies within it. I dont want to use arcpy ...
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0answers
16 views

polygonize some raster pixels based on their value in PostGIS

I need to extract and polygonize only those pixels of a raster that have a value (e.g.) greather than 2000.0 The reason is that I wish to do an operation like the following one (which is done only on ...
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1answer
42 views

Combining four shaded relief images into one single image using GIS overlay technique? [closed]

I have prepared four shaded relief images (hillshade) with four contrasting illumination directions 0°, 45°, 90° and 135°. I would like to combine four shaded relief images to produce one shaded ...
0
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1answer
212 views

problem to open a netCDF and create a raster file

I want to open a netCDF file and create a raster with ArcMap 10.2. The file contains the mean monthly temperature for Switzerland. I found it in meteoswiss web site. I tried to open it with the ...
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0answers
45 views

SRTM DEM and satellite DEM fusion

I have a SRTM DEM and a DEM derived from satellite (Cartosat). Both the DEMs are registered perfectly. Now I want to carry out a DEM 'fusion' process to derive a higher quality output DEM. I am not ...
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0answers
37 views

When subtracting two raster with different cell sizes using raster math, what value is used for smaller cells?

After reading the answer to a similar question (What will happen if we subtract two raster with different cell size using Raster Calculator?), I am still left with a question. When the raster with ...
4
votes
1answer
237 views

How to change field name in raster file?

I´m having a bit of an understanding problem with a DEM TIF file. I have a DEM TIF file which is served with Geoserver. When I click on the layer the WMSGetFeatureInfo gives me the following output: ...
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2answers
42 views

Averaging a big number of pixels within a several km radius

I work with ArcMap software and now I have the aim to average individual pixels within a several km radius from daily data for at least 1 month. So I made the grid with 4 km step (the step size is not ...
8
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2answers
585 views

How to create a solar intensity map for a garden plot?

I'm interested in creating a raster surface that depicts the average solar intensity per unit area for a small garden plot. I imagine the inputs into the model would be the following: Plot ...
0
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0answers
33 views

Calculating where the Z values of two rasters intersect

I have several raster layers which are depth horizons, one of these horizons cross cuts the others and I would like to calculate the line along which this occurs. i.e. the line along which the Z value ...
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0answers
23 views

Merge raster tiles in PostGIS

I have several raster tiles that are adjacent and non-overlapping, so they form a mosaic. I am trying to merge two adjacent rasters using PostGIS but am getting an error that they do not have the same ...
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1answer
53 views

how to produce a RASTER representing X coordinates [duplicate]

In a journal article I have read that two rasters, representing X and Y coordinates respectively (see attached figure), have been entered as predictors in a GIS-based Logistic Regression for a given ...
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0answers
24 views

Zonal statistics as table failed

I'm using ArcGIS 10 to perform "Zonal statistics as table" for my raster data (temperature). I would like to know that for each 50m level (for example, 0-50m), what is the average temperature. ...
1
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1answer
42 views

Raster appears like polygon in Arcmap

I copied rasters across into my geodatabase for a client but when they open the raster dataset in ArcMap they appear in tiles as shown in the image below. When I drag and drop individual rasters over ...
4
votes
1answer
51 views

Automate Exporting of Rasters Using Renderer in ArcGIS

It is possible to export rasters in ArcMap by right clicking the layer-> Data-> Export: You can then click 'Use Renderer' check box to ensure the image you export uses the current ...
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4answers
812 views

Australian Topo Map GeoTIFFs

Does anyone know if Australian topo map GeoTIFFs are made available anywhere (preferably for free)? LINZ makes them available in New Zealand - http://www.linz.govt.nz/topography/topo-maps/index.aspx ...
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2answers
118 views

Does a SRTM DEM image show details such as fields?

I'm working through the QGIS Training Manual where I have a step to get ... ... raster images (SRTM DEM) which cover the region you have selected for your course. SRTM DEM can be ...
2
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3answers
431 views

How to increase raster extent by filling extent with no data using ArcGIS Desktop without Spatial Analyst?

I am using feature to raster to rasterize water polygons. It only makes a raster the extent of the features in the polygons, whereas I would like it to be the extent of another existing .tif image. ...
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0answers
129 views

Importing GPS coordinates to extract multiple DN values in ERDAS

I have a set of GPS points (stored as a csv for now) and would like to import these points to ERDAS to find the DN values associated with each location. I am able to import a SHP to ERDAS but the ...