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

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2answers
38 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 ...
2
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1answer
19 views

Save raster from qgis using a compression

There is a method to save raster from qgis using a compression? For exemple from "Export map" in arcgis there are many options to compress the images depending on the file type (tiff, jpg...). I add ...
0
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1answer
10 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 ...
1
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0answers
16 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 ...
2
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1answer
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 ...
0
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2answers
12 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 ...
0
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0answers
25 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 ...
6
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2answers
54 views

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 ...
3
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1answer
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 ...
0
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2answers
35 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 ...
0
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0answers
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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0answers
48 views
+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 ...
0
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4answers
31 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 ...
0
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1answer
39 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 ...
1
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0answers
17 views

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 ...
1
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1answer
20 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 ...
1
vote
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). ...
0
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0answers
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 ...
0
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0answers
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.
1
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1answer
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 ...
0
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0answers
17 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 ...
2
votes
1answer
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.
2
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1answer
20 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 ...
1
vote
1answer
22 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 ...
4
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3answers
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 ...
1
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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 ...
0
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1answer
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). ...
1
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1answer
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, ...
1
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4answers
71 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 ...
1
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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 [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 ...
0
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2answers
22 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
27 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 ...
2
votes
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 ...
2
votes
1answer
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 ...
2
votes
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 ...
1
vote
3answers
54 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 ...
1
vote
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 ...
0
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0answers
43 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 ...
1
vote
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 ...
1
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0answers
47 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 ...
3
votes
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 ...
1
vote
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
votes
1answer
60 views

Fuzzy maps with QGIS/GRASSGIS

How to do fuzzy maps (FUZZY module in IDRISI) with QGIS/GRASSGIS?
0
votes
1answer
30 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 ...
2
votes
2answers
77 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
votes
3answers
59 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. ...
1
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1answer
27 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 ...
6
votes
1answer
57 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?