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

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How to assign contour values directly from raster extracted tiff [on hold]

How to assign contour values automatically from contours extraced from classified rasters...thanks
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13 views

Error in merging two raster files (precipitation) in QGIS

The newly computed geotiff shows the extent of both raster layers, but only the data of one. If I use identify features tool it gives me only the values of the visible part not of the other part. I ...
1
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13 views

Change detection between two Landsat scenes? [duplicate]

I want to do time series analysis and find change in NDVI. I have rasters where each pixel is represented by some value at a time. Also I have same thing but represented by points. And I would like ...
1
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14 views

Raster images overlaying each other but shouldn't

When I open a new map document and drag different raster images into the map the images stack on one another rather than form the complete image of a country. When I try zooming in, the multiple ...
2
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2answers
45 views

Raster image thresholding using python

I would appreciate if someone could guide me for applying thresholding technique to input raster image using Python. I intend to extract impervious surfaces from a high resolution raster such as ...
0
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0answers
13 views

Maxent does not create the distribution map

I've been using Maxent to run a model, the program produces multiple output files except the html file, the map pictures and the distribution map or raster file (.asc). Does anyone know why this could ...
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1answer
19 views

Enabling: Raster and Topology

I'm new to GIS and tile servers. I've installed TinyOWS pretty successfully except for what looks like to be some dependency issues. I have installed PostGIS and also PostgreSQL. PostGIS is supposed ...
1
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0answers
9 views

Recentering a tiled raster table in PostGIS?

Does anyone know a nice and easy way to recenter a tiled raster table in PostGIS? By recentering I mean that I have a raster that is centered on the Pacific, but I need to recenter it on ...
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1answer
33 views

Interpolation extent

the following pics will hopefully explain my problem. After interpolation an clipping the grid I get the result you can see on the pic. Next to the boundaries there are a lot of gaps caused by the ...
2
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2answers
52 views

Problem when opening a raster layer

I am a news user with QGIS API C++. In order to feel good with it I try some little program to explore class. I have download the tutorial 4 of the QGIS and adapted it to the 2.8 version but when I ...
1
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2answers
29 views

How to use r.mapcalculator to change values within a raster cost map to negative

I have created a cost map in r.cost module in GRASS (through QGIS). This is actually a distance map from a protected area and distance from protected area has been calculated in both directions. How I ...
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2answers
30 views

add multiple rasters, each located a branch too deep in separate folders - ArcGIS

I have a year of daily raster datasets (365) that I would like to use the Cell Statistics tool on; however, each raster is located in a separate folder so I cannot add all of them at once. ie: ...
3
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1answer
70 views

R - How to “smooth” a raster map

I am trying to create a map from raster data. The file came from a crop model, with resolution of 0.5 degree. Even when I disaggregate it (i.e. increase spatial resolution), the map looks really ...
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30 views

NDVI from raster to vector isnt working

I have question...can I make from raster img. vector file via qgis? Because Ive tried it on NDVI image and Ive only got one file with atribut table full of #null. Image is from landsat7... ...
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27 views

Obtaining NDVI data from selected area

I need to analyse NDVI (-1/1) change between years (05-10y). But still only under selected shapefile. To analyse the extent of each NDVI category. Any tips? I have tried to make vector from the NDVI ...
2
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1answer
9 views

Extract maximum raster value within a set radius to a point

I have lines (rivers) that don't exactly match a raster grid (flow accumulation). If they were exact, I could just extract the raster values to points I put along those lines. However the raster ...
0
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1answer
23 views

How to input Shapefile point data into a raster and have the raster adjust to the new data?

I have a shapefile with elevation data at specific points. I also have a raster that has incorrect elevation values, but the transition between pixals is what I need. Is there a way to put the values ...
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0answers
15 views

Raster alignment terminology?

I identify two types of raster alignment (assuming SRS is the same), but I am unsure of the correct terminology for these (or whether there is even a 'standard')? First, there is 'pixel alignment'; ...
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3answers
30 views

Creating a new raster layer based on mean of other raster layers, ignoring NA values in R

I am trying to create a new raster layer that is made up of the mean values from 7 other raster layers. I get results using overlay function mean: mean <- overlay(2000, 2001, 2002, 2003, 2004, ...
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20 views

plot rasters with the same line diagram

I have 6 raster files with continuous values for an area with the same extent. I have created a raster stack and I want to plot one line for each cell in the raster stack of my six rasters (like the ...
2
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22 views

clipping raster changes raster values?

I am working with BIOCLIM temperature/precipitation layers and I have noticed that when I clip the global raster down to a specific region, something happens and the raster value at a specific point ...
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3answers
38 views

Make all pixel in raster have the same value

I have a raster file with two categories: category 12 (total count=350) and category 14 (total county = 500). The attribute table looks like this: rowid Value Count 0 12 350 1 14 ...
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1answer
31 views

Displaying raster tiles from OSM data stored in a postgis server

I have been recently tasked with setting up a raster tile server that serves tiles from data pulled from a postgis store. I have managed to get a vector tile server up and running but I'm stuck on ...
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48 views

ArcPy reading a raster in a moving window?

I typically read large raster data using gdal and setting up a moving window of 256*256 pixels (for example). I recently had to do some processing using arcpy, so I did the same thing, using ...
4
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2answers
159 views

Calculating Shannon's diversity using moving window in R

I have a raster where each pixel is a particular vegetation type. I'm interested in the diversity of vegetation types around each pixel. I'd like to assign a Shannon's diversity index value (see ...
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12 views

Dynamic polygons grid with specified area based on raster

I'm interested if anyone have idea how to automatically create (maybe in R?) dynamic grid of polygons with specified approx. area (for example around 20000 m2) based raster data or points with values ...
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20 views

Converting NAD 83 to WGS 84 in PostGIS

My question is about the best way to convert from NAD 83 to WGS 84 in PostGIS. I have a PostGIS DB containing National Elevation Data rasters. The rasters are in NAD 83 and I would like to convert ...
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2answers
44 views

How to clip several raster datasets with a mask?

I would like to clip many images (raster datasets, input) with a mask (shapefile), so I would concentrate only in the images I need for my study area. Is it possible to do with Arc GIS 10,3 ? I ...
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1answer
65 views

ArcGIS, How do I get smoother contours?

I am trying to get nice smooth contours using ArcGIS. I have already smoothed out the DEM using focal statistics, simplified and smoothed the contours. The current result looks like this, which is way ...
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1answer
37 views

Modelling soil texture using ArcGIS for Desktop?

I am doing a project for automated soil mapping using landsat TM imagery, I have 3 output rasters: one for sand percentage one for silt percentage and a third for clay percentage. How can I ...
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1answer
20 views

Mod function in GRASS GIS

What is the equal of ArcGIS Raster calculator "Mod" function (Finds the remainder of the first raster when divided by the second raster on a cell-by-cell basis.) in r. mapcalc in GRASS GIS?
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15 views

Substract 2 rasters with Raster Calculator in ArcObjects (VB.NET)

I'm having a hard time substracting 2 raster with ArcObjects sdk 10.1. I keep getting a nullreference exception at the gp.execute() method, but I can't figure out where the problem is, I recall ...
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24 views

Making virtual raster with average values [duplicate]

I'm working with many raster files. Is there a way to make virtual raster with average values in each pixel. (QGIS) It's for an NDVI index of summer months over 5 years.
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23 views

How to create ROI in Semi-Automatic Classification plugin QGIS

while trying to classify landsat images, I get the following problem: I click on the pixel I want to define a ROI, but the ROI polygon that the plugin creates appears in a different part of the image ...
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16 views

Raster data for maximum temperature

I am looking for raster data for maximum temperature, ideally on a state by state basis (US) to make the file sizes smaller. Data would need to be weekly or daily going back to at least 2010. I ...
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13 views

Using USGS Raster Split but getting errors

I am working on an issue where I am trying to split the 2011 nlcd .img file into counties. I am really just looking at the midwest, so I have state county shapefiles for IA, OH, MN, MO, IL, IN and WI. ...
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1answer
16 views

arcpy CSV file to raster attribute table?

Using TableToTable_conversion I can convert a CSV file to a table in a geodatabase, but how can make this table be the default attribute table for a raster in the geodatabase? I can't seem to find ...
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1answer
28 views

Align pixels from two rasters with different cell sizes

I have two rasters in a PostGIS database that I want to be able to compare. The first raster is at 5m pixel resolution and the second raster is at 30m pixel resolution and is on a different grid. How ...
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45 views

How to compute NDSI in ArcGIS for Desktop?

How do I compute a Normalized Difference Snow Index (NDSI) in ArcGIS's Raster Calculator? I have a Landsat 8 scene (hdf4 format) that contains derived surface reflectance band-by-band. Each band is a ...
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1answer
30 views

I need to create a function in R that processes rasters in esri grid format [duplicate]

I have loads of data (6500 files that I need to process and find yearly winter sums/averages/variance for. the format for my naming system is Syyyymmdd_rp. Each file is in the same file folder. I ...
0
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1answer
41 views

mosaic raster image non georeferenced

I have several jpeg2000 tiles non georeferenced and covering a certain area. I know in qgis you can mosaic image using the merge tool but I have done it only using georeferenced images, which is quite ...
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15 views

Creating ROIS in Semi Automatic Classification pluggin Qgis

I am trying to classify a Landsat 8 image using the semi-automatic classification plugin in QGIS 2.6. When trying to define ROIS, I select a pixel of of interest, but the polygon is created ...
0
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1answer
22 views

Compare two rasters in R with the cell value from one replacing the cell value from another

I am trying to create a single raster from two rasters. The first raster is made up of all 0 values and the second is made up of the current date value (formatted in days from 001 to 365). The problem ...
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1answer
50 views

How to calculate raster statistics for each band in qgis

i need to calculate raster statistics for RGBN (4 channels, multiband image) rasters in QGIS. In Arcgis if you use "calculate statistics" in Arcatalog, statistics are calculated for every image band. ...
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1answer
23 views

GlobCover 2009 dataset - importing legend and colormap values into R

Does anyone know how to import a legend for a raster layer (loaded as a .tif) into R such that it can be attached to the raster file itself and used in plotting? In this case, I am using the GLC2009 ...
0
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1answer
29 views

Compare two rasters with raster overlay and replace cell value with variable

I want to compare 2 rasters and when there is a change from 2 to 1 create a new raster that replaces the cell where the change has been detected with the change variable. ## Finds Cells that have ...
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1answer
35 views

Merging USGS DEM files in ArcMap?

I'm trying to merge my DEM files into 2 separate files, one will have 4 files and the other will have 3. I've been reading every post from when someone asked this before for over an hour and I'm still ...
0
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1answer
21 views

How does ST_SnapToGrid work using nearest neighbor interpolation?

I have rasters in a PostGIS database that are not necessarily aligned (some rasters offset from the grid). I want to use ST_SnapToGrid to align all rasters to the same grid but have some questions ...
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18 views

How does `ST_Union` treat NULL values in a raster?

My question is about how ST_Union of rasters containing NULL values are handled. For example suppose I have two rasters that intersect but the values of the intersection are NULL in one of the ...
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1answer
32 views

How to extend raster data for larger boundary?

I am working on serveral raster data, but some of them are not fill data exactly with intended boundary (as shown in the picture below). What i want to do is firstly extend the raster data to intended ...