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

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How to extracting values of 40 plots from different bands of raster image in R?

I have 40 plots(samples) and I want to extract corresponding values from different bands of RapidEye image. So at the end I want to have totally 200 values of 5 bands in the format of txt. Till now I ...
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116 views

Find which latitude and longitude values are falling in which raster cells

I am an absolute beginner in analyzing geographic data with R. I have a database with longitude and latitude of around a million buildings in a country. I would like to find the average density of ...
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Setting NoData for a multiband raster?

I have an RGB orthoimage that has black area instead of NoData, as pictured here: When I use the SetNull tool, it does remove the black area, however it then turns it into a grayscale orthoimage, ...
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67 views

R raster stack 4 dimensions

I am trying to create a raster stack / brick from a list of ncdf files with the dimensions 160x160x24x1). r = stack(files) This gives me a raster stack but without the 4th dimensions which is ...
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61 views

How can I stop my map algebra being limited to the size of my smallest raster?

I have five input rasters and I'm using map algebra to find areas where all of them have a value over 75, areas where all of them are over 25, and areas where one or more are under 25. I can do this ...
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What Open Source (command line/API) method is there to orthorectify and georeference an aerial image given telemetry data?

How can I take an image and orthorectify it automatically with open source software? The information associated with each image is: camera specs latitude, longitude, elevation of the camera ...
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2k views

Speed of various raster data formats

I'm having trouble locating any discussion or comparative benchmarking of different raster file formats (e.g., for use in data analysis in R). Does anybody have any insight into why particular formats ...
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183 views

Problem using raster2pgsql to upload a raster to PostGIS

I am trying to upload a large number of 3 band rasters to a PostGIS database using raster2pgsql on the command line in Windows 7. Here is my command: raster2pgsql -I -C -s 27700 -F -t 100x100 -M F:\...
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68 views

Creating Polygon from a Raster

I have a Raster representing climate data. I converted the raster to vector using the tool raster to vector (Arc Map) and i got something like below: Can somebody help me out by guiding me in actual ...
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63 views

Why does gdalwarp's cubicspline method expand into nodata areas?

The image below shows part of a peninsula on the Australian island of Tasmania. The black pixels are 9" climate data with GDA94 (EPSG:4283) SRS, projected by QGIS on the fly to Australian Albers (EPSG:...
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4k views

How to import QGIS Raster into PostGIS

I have created a IDW heatmap using QGIS 1.8.0 and need to import the raster into PostGIS 2.0.1. QGIS saves the raster layer as a .asc file. How do you import the raster into PostGIS as a Raster? What ...
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38 views

use zonal statistics for only some part of input shapefile

I have a district shape file (districts have different size) and a raster file of precipitation (18 km grid square resolution). I want to calculate precipitation for each district which I did using ...
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319 views

QGIS: How to remove small areas from a raster layer?

I have a raster with the extent of some sinks. Now I need to delete the sinks smaller than 10 squaremetres, because they are not important for my project. How could I accomplish that? (It's ...
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1answer
139 views

How to merge vector buildings height layer with raster DEM to get solar maps in r.sun in Grass GIS?

Welcome, this is my first post. I have vector layer with buildings heights and vector/raster DEM file. I need to create solar maps with sun radiance values on the roof (and on surface, ofc). I am ...
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116 views

Is QGIS Server working like this?

On CentOS 7 I have QGIS Server and QGIS Desktop installed. In QGIS Desktop I created a project with raster and vector data and saved it in a ".qgs" file. Then I copied the file in "/var/www/html/cgi-...
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44 views

Visible altitude across a raster from a point

I have a raster surface model and I'm trying to determine the height an object would need to be at to be visible from an arbitrary point at an arbitrary altitude. I am currently using Grass and have ...
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75 views

Raster Image Importation

I am trying to open a raster image file in Arcmap 10.3 . I have the AUX File, a JGW file , 2 XML Document files ,and a RRD file. It imports into Arcmap 9. However, Arcmap 10.3 does not import the ...
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300 views

How to Convert from Point to Continuous Raster in ArcGIS 10.1?

I have a vector point dataset that I would like to convert to raster. The point-to-raster conversion tool creates a raster grid with spaces between each grid cell. I want to create a 'continuous' ...
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2answers
433 views

How to change the raster NoData value with ArcObjects?

I am trying to change the a raster's NoData value with ArcObjects and keep coming up short. Here is the code that I thought would work: IRasterDataset _dataset = ...get the dataset... object[] ...
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1answer
268 views

Create web map tiles from large images

I have 70Gb of raster data from drone photography that I need to serve via Openlayers. The data is currently provided as georeferenced jpegs each is 175Mgb in size. What is the best strategy to cut ...
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48 views

Segmentation and Classification in ERDAS

I have segmented an image inn erdas and will want to use it in a classification exercise, how do i proceed? My image is a low resolution 30m alos.
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79 views

gdallocationinfo used in javascript with node-gdal?

I've been scratching my head for a white trying to figure it out if it's possible to get pixel information from my rasters using gdallocationinfo in javascript. I found node-gdal, but after reading ...
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73 views

More than one dataset per year in ArcGIS Time Slider?

Using a Derived/Master Mosaic dataset as a container for source raster mosaics, I have successfully enabled the Time Slider feature in ArcGIS 10.1. The imagery on display was acquired most years ...
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2answers
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Applying stretch in ArcGIS Image Analysis Window?

I need to apply stretch to ArcGIS 10.1 exported raster. The best way to accomplish this task: Image Analysis Window, because there are fine tools to equalize raster data. 1 - This is my IRS-P6 24m ...
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27 views

Common methods of area comparison?

I have a set of raster area results, that represent a prediction for a specific loccation. I would like to measure accuracy of two methods, given the actual values, estimate-A method values and ...
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67 views

Why is QGIS only one label rendering at a time?

I'm new to QGIS, but I'm experiencing what I think is a bug. When I load the qgis_sample_data landcover raster and lakes vector layers, then enable labels for NAMES on that layer, I can only ever ...
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28 views

How to select a subset of rasters layers among thousands using QGIS?

I have thousands of rasters each one represents presence or absence of one species (0 absence and 1 presence). Some of them are completely absent in the landscape which I am working on. In other words,...
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How do you decide what interpolation method to use for resampling raster data?

The question pretty much says it all; are there hard and fast rules about which interpolation methods are suited to each kind of raster data? Any Golden rules, rules of thumb? Good books or articles ...
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118 views

GRASS 7.0 fill.dir crash

I am working on a 13407 lines * 11050 columns raster file (SRTM DEM, 30m) with a script that calls a series of hydrological modules in GRASS 7.0. The system I am using is a Windows server 2012 R2, 64 ...
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59 views

Stream to Feature, creating continuous streams

I have derived a stream network form a DEM through flowdirection and flowaccumulation in Arc 10.2 Hydrology toolbox. Have grids of stream order and stream link. Need to convert stream order grid, ...
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40 views

Rasters with duplicated data

I am working with a number of raster files that suddenly appear to have duplicated records. For example, I have a raster that classifies my study area into aquatic (value = 1) and terrestrial (value = ...
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86 views

Clip an interpolated raster using points or create an extent polygon from points using ArcGIS for Desktop

I have a point feature class that I have imported from lat longs in an Excel spreadsheet. I have created a raster image from these points however areas outside of the point set extent are interpolated....
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how to add vectorlayer in a mapcanvas with a raster

I am working in c++/qt4.8.5 with qgis api 2.8.2 For my application I had to load a raster in a mapcanvas, then with different action I had to add pint , line or polygon Is there a simply way to do ...
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230 views

Deciding variables for unsupervised image classification?

The results of an unsupervised image classification may vary A LOT depending on the variables you use from the beginning. These are the variables for the tool in ArcGIS:number of classes, minimum ...
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2answers
98 views

Change detection between binary rasters in QGis

I have two binary rasters, raster1 and raster2, which represent the distribution of grassland habitats inside an area in two different moments in time (raster1 = older, raster2 = recent). In both ...
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52 views

ArcGIS: Produce a raster mosaic dataset using a spatial query on another mosaic

Using ArcGIS 10.1 (Build 3143) I would like to create a relatively small raster mosaic dataset (the size of a city) based on a larger, existing one (the size of a state) using a single feature class ...
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2k views

Splitting raster into smaller chunks using GDAL?

I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS ...
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Is there a Raster Equivalent of the Split tool?

I have the DEM of a State in ERDAS Imagine (.img) format. I have a shapefile containing the counties of that state. I want to split the whole raster into DEMs of the individual counties. The counties ...
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224 views

How to remove nodata values from XYZ output with GDAL?

I have a buffered line route that is overlayed on a DEM: I've clipped the DEM to the buffered line, and exported it as an ADF ESRI grid file. I then used gdal_translate to convert it from the Arc/...
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Lat/Long grid array 360x720 for ArcMap raster layer?

I have two files (global temperature and precipitation), both in a 360x720 grid array (latxlong) in a csv file. I'm trying to add this to ArcMap 10.1 so I can use it in raster format. I've added the ...
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151 views

Debugging Flow Accumulation ERROR 999999 Error executing function The table was not found?

I have been trying run flow accumulation from the spatial analyst extension in Arc 10.3. I'm using a raster DEM from downloaded from the National Map. I used the fill and flow direction functions ...
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1answer
424 views

Converting large rasters to NumPy

I have a geodatabase that contains a large number of raster datasets - there are two rasters for each country in the world, and they are very large, in some cases up to 3GB per raster dataset. I ...
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36 views

How to generate map tiles including world files in QGIS?

Is there any way to export bitmap tiles including world files from a QGIS project? I've tried QTiles but it seems not to support world files.
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46 views

Opening .dir ASCII files [on hold]

I'm working on some ecological models and one of the datasets I'd love to utilize is that of ECOCLIMAP, its files consist of a hdr metadata file and a dir ASCII file, which I believe is built for the ...
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33 views

how to creat a histogram from two raster layer?

I have two raster layer ( raster layer 1 and raster layer 2) that was made by kernel density. now, i want to create a graph that vertical axis shows the density of each cell in raster layer 1 and ...
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Changing datasource of a .lyr file results in empty layer with empty symbology (ArcObjects VB.NET)

I'm having a hard time adding my grid to the map and changing its symbology with an existing lyr file. I have found a great post by Neil Clemmons that explains this, but it doesn't work for me. I ...
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why ENVI displays colormap classified image as a RGB image

I want to do accuracy assessment in ENVI. My ground through image has 19 classes (Unsigned 16bit) when I opened it ERDAS and ARCGIS. But when I opened it in ENVI, ENVI displays these image as a RGB ...
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26 views

Raster ordination

I have 4 raster layers from one Landsat image. One is NDVI and others are layers which shows different soil units (Sabin's color composite). My NDVI shows different class of vegetation (grassland, ...
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1answer
68 views

write python ndarray to raster

I think I understood the steps to write an array to a raster file using python. however it doesn't work in my case and I don't know why. I have an array that I want to write to a Geotiff with Swiss ...
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1answer
62 views

Change number of cells in raster using GDAL?

i have 5 raster files and i want to merge them to one file with exact 50x50 cells because i have an R script to process it later. I tried the ArcGIS function "mosaic to raster" but it delivers a ...