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

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Kriging with Raster Data in ArcGIS

I have MODIS satellite imagery that depicts a range of surface temperatures. However, many of the cells are missing values. I think I need to perform Kriging in order to obtain an average value for ...
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14 views

How to calculate percentage area cover using Focal Statistics

I am trying to produce raster outputs in ArcGIS for later use in MaxEnt to model species distributions, and want to produce variables with statistics on the percentage cover of different habitat ...
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14 views

Batch Conditional Test - For Loop with a Group of Rasters

How do I ask a “for loop” to operate on groups of three files folder (e.x. files A, B, C), then files B, C, D, and then files C, D, E, and so on? I have a folder full of rasters (.tif): RasterA.tif, ...
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Urban Heat Island USING ENVI

I have downloaded MODIS images for a specified area.. Its my first time that I am working on UHI (Urban Heat Island).. I need to know the methods to work on it.. I am using ENVI for this.
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35 views

Why does my clipped raster seem to be slightly moved?

I'm having some problems with clipping rasters. I started clipping my raster using extents, but I saw that the clipped raster is different from the original raster. I created a virtual raster to use ...
3
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229 views

Build Raster Attribute Table with GDAL Utilities

Is there a way to build a raster attribute table using one of the GDAL utilities? I know you can view it using gdalinfo and I have successfully created one using Python, but it would be so much ...
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14 views

Preserve polygon boundaries when vectorizing a raster according to a polygon vector

I have a raster which I clip by some polygons and then convert to polygon. I would like to obtain the same number of polygons in both my vector files. The problem is that some areas in the vector ...
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1answer
33 views

how to calculate area verses each NDVI value?

I created an NDVI map, I want to calculate area of vegetation verses the respective NDVI value of the given map. Which tools are used for this process and what steps are required?
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98 views

Analyse slope gradient from LiDAR .asc data

I'm new to using QGIS. I have purchased some LiDAR data which downloads as .asc format, is there a way to analyse the terrain slope angle from this data or does it need to be converted into DEM? ...
2
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1answer
20 views

Intersect shapefile with raster, then determine proportion of each raster value?

Using the arcpy module in Python, I want to find the proportion of each pixel value within the boundary of an overlaying polygon. (The polygon is in a shapefile.) For example, there are 10 possible ...
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13 views

TIMESAT input image requirement?

I tried to work on TIMESAT but always facing a problem. Here is the method I have used. Seems correct, but I get a warning at the end. I have created a NDVI file from ENVI 4.8 >> Transform >> NDVI ...
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125 views

Merging Raster: ImportError: No module named _gdal_array

When I try to merge rasters I got following error message: _gdal_array = swig_import_helper() File "C:\PROGRA~1\QGISDU~1\apps\Python27\lib\site-packages\osgeo\gdal_array.py", line 18, in ...
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33 views

What's the reason for this Invalid Layer “Cannot open GDAL dataset …” error

When adding a rasterfile with QGIS python console there appears an error when the first letter of a rasterfile to be added is not written in capital letters. Why this behaviour? Example case1: ...
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1answer
29 views

Is this a known issue in gaps between masked raster and spatial polygon in R with mask command?

This is my codes raster file: RAD polygon(shape): ws_sfc RAD.sub <- crop(RAD, extent(ws_sfc)) plot(RAD.sub) RAD.sub <- mask(RAD.sub, ws_sfc) plot(RAD.sub) plot(ws_sfc, add = TRUE) ...
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76 views

NAs not allowed error message in attempt to plot raster object in R

I have imported a clipped raster (performed in ArcGIS 10.1) from the National Landcover Dataset into R, but when I try to plot I get the following error message. Error in .readCellsGDAL(x, ...
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19 views

How to calculate a raster area with Grass - help for query by coordinates [on hold]

I'm working with Grass. I have a raster digital elevation model and I have analyzed the watershed flow. Now I have to: calculate the watershed area; find an identity in the digital elevation model ...
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1answer
24 views

removing spurious lines in raster before or after vector conversion?

I'm looking for a feature/function in either python opencv/ndimage/gdal/etc. or qgis/saga/grass that will help clean up a skeletonized image that I'd like to vectorize into a shapefile of ...
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20 views

Using ArcGIS Polygon to Raster tool does not divide resulting raster on cells?

I try to create raster composed of small (5x5 m) cells (pixels) from a polygon in ArcGIS-10. I created a polygon (as a single object), and use Feature to Raster Tool and Polygon to Raster tool (of ...
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2answers
230 views

Per-pixel (statistical) calculations on a raster stack using GDAL

In R, it's relatively trivial to perform per pixel calculations based on a raster stack (e.g., get std.dev for each pixel on a 12 layer GeoTIFF). Unfortunately, the speed is less than desirable when ...
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2answers
26 views

Aggregating rasters with GDAL

I have a set of files that have been mosaiced into a global VRT in a particular projection and resolution. However, I have a need to report statistics on a (say) one degree grid, where the reported ...
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1answer
458 views

Create raster distance around a single point feature class

Okay, so I'm relatively new to ArcMap and I'm trying to use the Fuzzy membership for suitability test. I have a single point feature class that I want to use for this analysis. I know that in order to ...
3
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1answer
127 views

Continuous color band for a raster legend in QGIS composer legend

I'm looking for a way to insert continuous colour legend for a raster layer. I managed to create discrete symbols with values along the bar, but I would like to have a continuous bar with some values ...
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21 views

How to calculate 90% confidence interval in a raster stack

I have a stack of grid files (23) in ASC format from a MODIS sensor and I need to calculate a 90% confidence interval, mean, min, etc, for each one in R, how can I do that? specially the interval. ...
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56 views

Classified Images of RandomForest-Classification look clustered

I performed a RF-classification. I have 6 bands, ~250 trainingpoints in a shapefile, OOB estimate of error rate: 1.56% Picture of take trainingpoints added. My code: ...
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1answer
39 views

Processing RGB+NIR raster into RBG?

I have a Geoeye 1 satellite photo that's a 4-band multispectral B,G,R,NIR, 11 bit raster. Ultimately I want to publish this raster as a web service (using Mapserver). I opened up the raster in Qgis ...
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Raster diff: how to check if images have identical values?

Is there a means to check to see if any 2 given raster layers have identical content? We have a problem on our corporate shared storage volume: it's now so big that it takes over 3 days to conduct a ...
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3answers
38 views

How to increase raster extent by filling extent with no data using ArcGIS Desktop without Spatial Analyst?

I am using feature to raster to rasterize water polygons. It only makes a raster the extent of the features in the polygons, whereas I would like it to be the extent of another existing .tif image. ...
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1answer
566 views

Problem in importing raster data from PostGIS to Geoserver

I am using Opengeo Suite 3.0.2, PostGIS 2.0.3 and PostgreSQl 9.2. I am trying to import raster data from PostGIS to Geoserver but facing an error. I follow this tutorial link to import the raster ...
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26 views

How to Interpolate very large datasets in QGIS

I am working with a very large set of point data, (XYAttribute) which I wish to display as a raster. I've been using Interpolate, this is successful but very slow. I have other programmes that simply ...
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49 views

Error: .asc is not a supported raster data source

I am new using QGIS and struggling with this error "...... .asc is not a supported raster data source" when trying to add a ."asc" file as a raster. I downloaded the files from ...
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31 views

Flow accumulation raster loading in QGIS 2.4.0 with null values (but flow direction loading ok!)

I have been tasked with creating an open-source hydrology dataset for a community group. To do this I have exported the flow direction and flow accumulation rasters from ArcMap as TIFF files and then ...
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419 views

Clip_management to raster extent outputs larger raster than raster extent

Using Python and ArcMap 10.0 SP5, I'm trying to reproject and clip a large input raster to exactly the same grid as a smaller target raster (same extent, pixel sizes and projection). The problem is ...
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65 views

Merging raster and vector not working

I have 1 vector layer (counties) and 1 raster layer (population density). I have tried merging these two, so that I can examine population density within a county, but I have had no luck. It just ...
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99 views

How can I see average of raster value over certain area, marked by mouse?

I have a raster in Quantum GIS and I am just exploring it. How can I see average of raster value over certain area, marked by mouse? In other words: How can I select particular area in QGIS? How can ...
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33 views

Using R to subtract the polygon area of one shp file from another

I'm looking to produce a map from two separate maps in R. My Maps files are as follows: ftp://ftp.cpc.ncep.noaa.gov/GIS/us_tempprcpfcst/610prcp_20140822.zip #Map1 ...
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22 views

Measure Displacement in ERDAS Imagine

How do I measure the displacement between two images in ERDAS Imagine. What tool do I use? I have looked in the ERDAS field guide.
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21 views

IMG and geoTIFF raster extraction

everyone. I'm very new to GIS technologies. Somehow, i need to extract raster(RGB data) data from geoTIFF and IMG files. What is the fastest way doing it?
3
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1answer
219 views

How do I write XML metadata with Python?

Some Python software I have written generates raster files via GDAL. I would like the software to create an XML metadata file for each raster so that I can include details about how the raster was ...
3
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1answer
42 views

How to model a geodesic grid in PostGIS?

Abstract I've decided to use PostGIS for a hobby game project. It requires a lot of units allocated on the surface of a planet. I'd like to model not only the units (simple points), but also their ...
3
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1answer
223 views

Can ArcGIS handle missing values to create a contour map?

I am trying to create a contour map for a waterbody. It turns out that in several locations there is no data. I just don't want to use the missing values as zero in ArcGIS because it would create ...
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433 views

What is the correct way to convert a USGS Orthoimage from WorldImage format to tiled GeoTiff for GeoServer?

USGS provides different resolution orthoimage quadrangles in the WorldImage format (*.tif with an accompanying *.tfw world file). Some of these quadrangles can be used by GeoServer (2.1.0 - 2.1.2) by ...
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37 views

How to produce “SpatialPixelsDataFrame” from stacked RasterLayer?

How to produce "SpatialPixelsDataFrame" from staccked RasterLayer ? I have a stacked rasterlayer and I want to convert them to SpatialPixelsDataFrame. RasterLayer information is > RAD.all[[1]] ...
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1answer
167 views

How to draw a custom map on top of base layer

I'm looking for the easiest way to draw a custom layer and export it as a tile cache. Basically what I would like to be able to do is load a base layer, and then draw objects and annotations on top ...
4
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3answers
492 views

Finding outliers with wrong Z values in LIDAR data

I have more than 2000 XYZ (only ground points) .txt files and I have to do Quality Control (QC). Let's say I have file, which I converted to multipoint (or even singlepart feature). I have mean Z ...
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24 views

Postgis Raster Unions Color Issues

Can someone explain to me what I am doing wrong here as I think I do not properly understand postgis raster bands. I have a set of geometries that I want to merge with a raster and created a raster ...
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2answers
94 views

Reprojecting Natural Earth raster into natearth projection with gdalwarp causing black squares?

I'm trying to reproject the Natural Earth 2 raster layer (http://www.naturalearthdata.com/downloads/10m-raster-data/10m-natural-earth-2/) into the natural earth projection ...
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85 views

Step-by-step: How do I extract Raster values from Polygon overlay with Q-GIS or R?

I am writing my master thesis at the moment and am having the exact same problem as user Curley in this question: I first need to overlay a Corine 2006 raster with a polygon layer (2638 polygons). ...
4
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1answer
198 views

How to change field name in raster file?

I´m having a bit of an understanding problem with a DEM TIF file. I have a DEM TIF file which is served with Geoserver. When I click on the layer the WMSGetFeatureInfo gives me the following output: ...
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2answers
66 views

How to access raster NoData value?

I am trying to programmatically access the NoData value in a raster dataset as shown in the screenshot. Two tools that come to mind to describe raster properties do not seem to be able to describe ...
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2answers
62 views

R -plot 12 images per plot or save 12 images per image file in R

Here is R script and my question is How can I plot 12 images per plot or save 12 images per image file because I have total 864 images. RAD1998 <- raster(paste(getwd(), "/1998bil ...