Tagged Questions

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

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5 views

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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7 views

Creating a Raster of Road Distance to Point

I'm trying to create a raster of distance to a certain point on a road; preferably using the Road Graph package or something similar in QGIS (using v2.6). I was wondering if I could create this ...
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16 views

Raster legend visualisation problem

With the new 2.6 QGIS version I often have problems with raster colors. Is there a problem I could solve by myself?
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1answer
24 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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13 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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1answer
19 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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13 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
18 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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3answers
223 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
48 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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1answer
26 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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1answer
21 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
54 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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1answer
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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0answers
22 views

Raster overview hierarchy in WMS

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
21 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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0answers
25 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
34 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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1answer
29 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
37 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
49 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
29 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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0answers
37 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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0answers
39 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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1answer
40 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
25 views

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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0answers
17 views

“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 ...
2
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1answer
53 views

Fuzzy maps with QGIS/GRASSGIS

How to do fuzzy maps (FUZZY module in IDRISI) with QGIS/GRASSGIS?
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1answer
28 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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2answers
74 views

Where to store Raster data?

I will soon have to plan where and how our raster data will be stored as we will be upgrading from ArcGIS 10.0 to ArcGIS 10.2. The following questions first need to be addressed before I can make any ...
3
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3answers
56 views

Which raster resolution (DEM) can I get out of lidar data with variable grid width?

I have ASCII files in *.xyz format and want to generate a DEM out of it. According to the information about the data the *.xyz files are containing variable grid widths - from 1 meter to 4 meter. ...
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1answer
23 views

How to make raster DEM from SHP with FME?

I have a Point Featureclass in an ESRI FGDB with 22 Million points. The points have a distance of 10m from each other.I would like to create a raster DEM using SAFE FME 2014. Looking at the ...
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1answer
51 views

What resampling technique should be used to reproject an altitude raster?

Does anyone know whether I should choose: nearest, bilinear, cubic or majority when projecting the WorldClim altitude raster layer?
2
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1answer
50 views

Reclass in QGIS?

I'm new in QGIS and I'm trying to reclass a raster with reclassify grid values. I want to reclassify by table, however fixed table has only 3 rows and I need some more, but button to add is not ...
2
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1answer
23 views

Raster origin is incorrect, does not properly overlay with vector in same CRS

Two layers, both allegedly WGS84, one vector layer of the Midwestern US, one raster layer with coverage of the entire US. The vector layer renders correctly (coordinates are correct), but the raster ...
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0answers
16 views

How to create contour lines from 4 hgt files? [duplicate]

Is it possible to draw contour line for 4 different .hgt raster in one operation ? If I load them to cover a large region, do I need to extract-> contour for each of them or is there a tool opposite ...
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0answers
30 views

Creating New Field in Raster Attribute Table with Corresponding Values from another Raster

I have a raster layer that represents surface temperature for the State of Arizona. I also created a raster using the interpolation function to represent air temperature for the State of Arizona. I'm ...
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1answer
19 views

Accessibility indication from points

I will simplify my question to be better understood. Let's suppose my study area is consisted by settlements A and B. They both have the same population (1000 people each). Each settlement was ...
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0answers
8 views

Change “World Size” with gdal2tiles.py

When I use the flag "-p 'geodetic'", the output is a world that is 512x256px at zoom level 0. In order for it to overlay with other datasets, I need it to be 640x320px at zoom level 0. I am looking ...
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0answers
30 views

How to batch classify a multi-temporal raster image stack?

I am using dense time stacks of remotely sensed imagery to analyse vegetation change in the Arctic from 1984-2010 for one scene. I will be needing to classify each image, likely using the Maximum ...
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0answers
19 views

Best Management - Building, Site and Development Plans

We have thousands of scanned plans sets for various buildings, sites and developments that have been acquired over the years. The plan sheets are saved as tiff files and the entire plan set is saved ...
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1answer
11 views

How to reproduce contour-style labeling with rasterVis::contourplot?

I am currently working with a digital elevation model (DEM) of Mt. Kilimanjaro, Tanzania. The referring raster grid can be downloaded from DIVA-GIS (Country: Tanzania; Subject: Elevation). After ...
4
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1answer
64 views

How do I combine bands in a tiff then convert to grayscale?

I have a large mosaic of tiffs in which I need to do the following: -Combine bands 4,3,2, for an infrared image then convert the image to grayscale without producing another dataset -This is easy on ...
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0answers
14 views

How to set m parameter of clusterR function in R?

I want to manage a clustered computation on raster and thus use the "clusterR" function in R (package 'raster'). However, there's a tuning m parameter to set, but the only explanation about this ...
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0answers
23 views

different data range of raster file in mapserver and qgis

a NetCDF file with only one band with a data range from [0,1.1]. IDV & QGIS identifies it correctly, however gdalinfo finds the data range [1,26505]. Or could it be possible that gdalinfo is right ...
0
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1answer
28 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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2answers
38 views

Running Point To Raster has output coordinate system different from input?

I need to transform a DEM from a Point-Feature-Class (Shape) to raster (GRID). For that I'm using the tool 'point to raster' and it works perfectly. The only problem is that it seems to change the ...
3
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2answers
70 views

How can I determine which raster attribute covers the highest area of a polygon?

I'm relatively new to GIS and QGIS but I have a problem that I'm not certain how to solve. I searched here for relevant information but found none. (Or, I used incorrect search terms.) My problem ...
2
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0answers
23 views

How to calculate the slope with isolines/raster?

I'm trying to calculate the slope (in %) in ArcGis 9.3, but don't remember how it works. I already did it some time ago, but this time it doesn't work... I used a shapefile with Isolines (see ...