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

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Converting a table to a raster for clipping

I have a series of tables (TAB files) that represent the calculated values for a corresponding .tif image. These tab files have the same number of rows and columns as pixels in the tif images. The ...
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Has anyone success using subset an image such as NAIP?

Has anyone any luck subsetting a small part out from NAIP? I'd like to hear your feedback on pros or cons on how to subset an image from NAIP despite they are in mrsid and their uncompressed file size ...
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QGIS Raster moving when Majority filter

I'm running QGIS 2.01 Dufour on Linux Mint. Data & project are WGS84. I'm trying to smooth a grid & following other posts here I've used the Majority filter. This is looking helpful, but the ...
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20 views

In qgis using python, how can I get multiple pixels from a raster based on a vector point file

I just started working with qgis, and for the life of me I cannot figure out how to solve this problem: I have several points of interest, these are stored in a shape file (just simple points). I ...
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40 views

How to calculate percentage of selected area from DEM?

I am working with elevation data and performed a local operation to convert it from meters to feet. I am interested in finding the area (expressed in percentage) that is above 4000 ft, but I have ...
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34 views

Save map in raster format from QGIS using compression

Is there a method to save a map in raster format from QGIS using compression? For exemple from "Export map" in ArcGIS there are many options to compress the images depending on the file type (tiff, ...
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15 views

Remove sections, defined by a line or polygon, from a raster in QGIS

(QGIS 2.6.0 on Windows.) I have created a raster layer of heights using the TIN interpolate function. I also have another raster layer with more accurate information on the height of particular areas ...
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23 views

Raster: how to locate cells having nodata

I am new to oracle spatial. I am using SDO_GEOR package's getNoData prcedure. the results are populated in following format. MDSYS.SDO_RANGE(MDSYS.SDO_RANGE(-32768,null)) My questions are: Is ...
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23 views

fit point with raster data figure out those points belong to, and add column and row to represent it in ArcGIS 10.2.2

I have an X-Y point data file, with which has latitude and longitude. I'd like to be fit it with the raster data, then add column and row data on the X-Y point data file. first i created the attribute ...
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13 views

Creating new raster based on spatial extent and classes of one raster and average of another using ArcMap?

I have a raster that is split into classes and I wanted to make a new raster with this raster's spatial extent and classes but displaying the average values from a different raster. I am not really ...
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30 views

QGIS 2.4.0 Setting raster layer to singlebandpseudocolor using minimum and maximum raster values

I am using QGIS Chugiak 2.4.0, and I have some code in which I want to: Add raster layer to map canvas Look for the minimum and maximum raster value Apply singleband pseudocolor render type for the ...
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How to decide how to “stretch” raster imagery?

I have to symbolize a digital elevation model. ArcMap offers many different setting for stretching the symbology which all give widely different results. Some stretch methods symbolize the data so ...
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60 views

What effect does standard deviation have on the display of DEM rasters?

I need to explain why ArcGIS offers the function "standard deviation" when symbolizing rasters with the Stretch method. The Standard Deviation is a measure of how spread out numbers are and is ...
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2answers
39 views

Using raster to clip vector data

I have high res raster data covering 2million km sq, with a field where each cell has a value from 0 to 100. I need to create a "mask" using the cells with a value over 12 in that field. I then need ...
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28 views

raster and vector misalignment

my vector and raster datasets align perfectly fine in Arcmap but not in QGIS, any suggestion on solving this dilemma is very much appreciated.
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+50

merging raster aerials in QGIS issue

I follow the instructions here very closely and yet every time QGIS gets caught in a loop. It takes a few small rasters totally less than 100mb and creates HUGE gb files and will not stop until ...
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4answers
32 views

How can I join all data of two raster datasets in ArcMap 10.2?

I have two raster datasets in ArcMap10.2. One is displaying rails and one that is displaying a 100m Buffer to both sides of it. My cellsize is 100x100m. What I want is to combine the rails AND the ...
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42 views

Modifying raster values in a zone with a math expression

I'm currently doing an SIG project with the goal of calculating groundwater volumes in chalk and silex residuals aquifers. I have point data of underground water, chalk roof, and floor elevations, as ...
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Web Server/Technology to work with Raster-Imagery Data

I am in the process of designing a web application which will allow the end users to load raster imagery data (size range from 300 MB to 500 MB) as a back ground map and a corresponding OLD JPEG image ...
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26 views

Arcpy reclassify all values to same number

Using ArcGIS 10.1 and arcpy, is there a way to reclassify all values of a raster file to the same value (leaving NoData Values as "NoData")? Lets assume that I have no way of knowing what the actual ...
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3answers
28 views

How to narrow raster features to single cell width?

Are there any tools or existing workflow which convert raster features (such as roads, rivers, electric lines etc.) which are (or can be) multiple cells wide to a single cell widht (i.e, center line). ...
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29 views

Creating a Raster of Road Distance to Point

I am using QGIS 2.6. This question is in two related parts: I'm trying to create a raster of travel time from one point to another point travelling via the road system. Each raster pixel will roughly ...
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45 views

QGIS raster symbology problem in 2.6

With the new 2.6 QGIS version I often have problems with raster colors. For some reason certain pixels do not display initially, but if I move the raster a little spatially they show up.
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28 views

Defining polygons based on thickness maps using ArcGIS for Desktop?

I want to find and create polygons that demarcates three different inflection points in a thickness raster: where the thickness start to increase, where the thickness is at its max and where it starts ...
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18 views

Adding Raster Layer in C++ application always result in layer invalid

I am trying to add a raster layer in c++ application with QtCreator and QGIS 2.6.0. My code is as follows: QgsRasterLayer * layer = new ...
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24 views

area elevation distribution with QGIS

I have a raster DEM and a polygon covering a part of it. I need an area-elevation distribution (i.e. how many m2 are in which elevation interval). 20m intervals will be fine. I cant figure it out.
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21 views

Percentage of a polygon at, or less than, a specific height (supplied by a raster)

I am using QGIS to process some LIDAR data. I need to be able to define the area of a pond with respect to its depth (i.e it is 100m^2 at 32mAOD and 500m^2 at 33mAOD). Is there a way of finding the ...
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1answer
24 views

Prepare raster data for wms using geoserver!

I have some orthophoto of different resolution (urban 8cm pixel, hill 20cm pixel, mountain 35 cm pixel) which cover an area of 28000 km2. Those are in jpg format, already georeferenced. I need to ...
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239 views

Is there a standard for the coordinates of pixels in georeferenced rasters ?

We are working with different raster datasets, and the pixel coordinates are either stored at the center of the pixel or at one corner. The information is usually provided in the metadata, but ...
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1answer
52 views

Do rasters other than “north up” exist in the wild?

"North-up" (as I understand it) refers to raster images stored with the northerly direction at top, and each subsequent line of pixels is a bit farther southward. Rasters' georeferencing metadata ...
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31 views

Will Processing without a Spatial Reference cause Issues?

I was given a bunch of ASCII files that I needed to convert to raster and then create maps from. For some maps I had to do a simple difference calculation between two rasters (did this in ArcMap). ...
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23 views

Only run r.neighbors if cell meets criteria

This is my first time using GRASS to work with Rasters, so please excuse my lack of knowledge on the subject. I want to run the GRASS r.neighbors function on cells that meet a specific criteria, ...
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4answers
74 views

Apply Symbology to Rasters using Arcpy Script

I have an ArcPy script to apply the symbology of one raster layer to all of the raster layers in the table of contents. I have used this script before with feature layers instead of raster layers, and ...
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20 views

Adding images to raster field in batch

So I've got about 300 records in an attribute table that each need an image to go with them. I've created a raster field on the table, and I've got all the needed images as rasters in the same GDB. ...
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22 views

Raster overview hierarchy in WMS [duplicate]

I have rasters with low resolution which covers the whole area, and in certain spots i have some rasters with higher resolution which covers small parts of the same are covered by the lower raster ...
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2answers
23 views

Extract/copy a subset of rasters from a mosaic dataset

I have a mosaic dataset of 421 images and I want to extract just a few of them to give to a client. Rather than click through the folder selecting the files (because they are not contiguous) I want to ...
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29 views

How to convert a 3-band image to a color-mapped one-band 8-bit image with ArcGIS or FME?

I have a 3 band image which needs to be converted to a 1 band image with colour-map so that I can assign different colours to the values. How can I first create a 1 band image out of RGB images with ...
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1answer
37 views

Export band names with NetCDF file in R

I am using R to work with multiband raster files and am running into a problem. I have named the bands, but when I export in netcdf format, the band names are being stripped. Anyone know how to ...
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31 views

average certain raster cells in R

If I have two rasters, let's say x1 and x2, that are the same dimensions, how can I take the average of the two but only where both have data to have a third raster x3 that is a composite of the first ...
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1answer
40 views

Determine spatial average of several tiff files

I am relatively new to GIS. I have a set of tiff files containing a raster each. I would like to average them, though their extents are slightly different. They each have their geospatial data ...
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3answers
55 views

Creating buffer around particular raster cells using ArcGIS for Desktop?

I would like to draw 100m buffers around particular raster cells (artificial surfaces) in my LandCover raster layer in ArcMap10.2. The Buffer tool only works with polygon and the Expand tool always ...
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2answers
30 views

Line density to polygon

I have performed Line Density and the results is a Raster...I want to make polygons from this Raster, but I cannot do it... It shows me when I put this raster as Input raster: "One or more Dropped ...
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44 views

Reclassify raster value

I'm curious if anyone has been able to change one individual value in a raster file? I'm using Arc 10.2 and trying to change the value 99 to -2 for 144 files using model builder. So far, I've only ...
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1answer
12 views

Original Size from Tiled PostGIS Raster

Does anybody know of a quick and easy get the original height and width (rows and columns) of a tiled raster in PostGIS? Using a combination of items I know this can be calculated so just wondering ...
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48 views

Permission denied when clipping raster

Trying to use raster extraction clipper to prepare a selected area of the map for generating contours - keep getting the error message: ERROR 1: TIFFOpen:everest_gmted30.tif: Permission denied ...
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42 views

Extracting raster data outside of clip

I'm trying to extract Sea Surface Temp raster (floating integer) that includes both sea temp and land surface temp. I want the data outside of a clip. I've clipped the coastline with a polygon in ...
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2answers
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arcpy.Raster.save(*.jpg) - format unknown

The following Python script returns the error on the final line, "RuntimeError: ERROR 010093: Output raster format UNKNOWN is unsupported.": import arcpy inRaster = ...
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“Points To Raster Tool”- Output pixel values differ from original point values

I am trying to convert an evenly spaced set of points to a raster using the "Points To Raster" tool in 10.1. Problem: Generally, the raster makes sense, but in some areas the cell values differ quite ...
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61 views

Fuzzy maps with QGIS/GRASSGIS

How to do fuzzy maps (FUZZY module in IDRISI) with QGIS/GRASSGIS?
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31 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 ...