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

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Different obs. when I extract raster values from polygons in R

I have two raster layers with the same projection, extent and resolution: r1: class : RasterLayer dimensions : 33434, 89431, 2990036054 (nrow, ncol, ncell) resolution : 0.001447053, ...
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43 views

Large Rasters in ArcGIS & MapInfo

My geoscientists like to work with MapInfo and ArcGIS. I require a common 1 band raster format that can hold obscene amounts of data without damaging the data (compression). I have tried .tif and ...
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17 views

Extract value from Raster data by elevation

I have one raster data (AVHRR NDVI value) and one dtm data (elevation value). Is there anyway to know the NDVI value by 50m interval elevation? For example, I wanna know what is the NDVI value for ...
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1answer
35 views

Resolution problem in QGIS raster

I have a raster file I need to clip. I created a virtual raster which I used to "copy" the extent from in QGIS raster calculator. As a result, I get the raster with the extent I need, but pixel size ...
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15 views

Raster to point: 10 rows in the attribute table per 1 point

I have just made Raster to Point operation. In the output, if I select a point on the map, in the attribute table appear I have just selected 10 rows. How is it possible? Where, in the Raster to Point ...
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1answer
43 views

How to change no data value from -32768 to -3.40282e+38 in raster in QGIS?

I am trying to change the null values of a raster from -32768 to -3.40282e+38 in QGIS. I tried using warp tool setting the no data values to my desired number but it did not change it. Then I used ...
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9 views

PostGis - ST_AsRaster returning raster smaller than reference raster

I am trying to convert a point geometry to a raster using a reference raster: SELECT ST_AsRaster(my_points, ref_raster) FROM my_table This works fine except it is only returning a subset of the ...
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17 views

R raster package split image into multiples [on hold]

I have an image as below. It is 2579*2388 pixels. Lets assume that it's bottom left corner is at 0,0. From that image I want to create multiple images as follows and save them in the working folder. ...
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10 views

Raster Copy: Output bit size does not match specified value

Using ArcGIS (Map/Catalog) 10.0. I have a raster file (kdens) developed from point data using the kernel density tool. It is 32-bit float file format. I need this file converted to a polygon ...
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3 views

Use of OTB BandmathX

I have a couple of three-band satellite images that I want to apply an expression to and get a three-band output. The expression is of a simple form: output_pixel= (input_pixel*d^2)/cos e After ...
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2answers
24 views

Include non-raster object in overlay function in R

I have two raster objects and I would like to calculate values of the first conditional on values in the second. I am currently using the overlay function, but unfortunately I can't seem to pass non ...
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1answer
21 views

Combining continuous raster and point in ArcGIS for Desktop?

I have a layer that's a topographic map of a mountain range, represented by a continuous raster. I have another layer that is just points, representing where the summits are. How can I use the ...
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1answer
20 views

Python error in polygon to raster conversion

I want to convert polygon to raster. I converted the dbf file ( "cntymam") to table view to make use in the conversion. I am getting a error that the parameters are not called and also with the grid ...
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41 views

How to set raster projection in R

I am new to R and grib files. library(raster) I have a "grd" file in and I am trying to set the coordinates to polar stereographic projection r <- raster("p190001.grd") # class : ...
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25 views

ArcGIS 10 restricted WEIGHTED Flow Accumulation

I have a question very similar to one asked by wxfox4god on 12th June 2013 ("Arcmap 10 restrict Flow Accumulation") that was answered by whuber. (I have had to post it as a new question as I do not ...
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26 views

How to create an attribute table from a Euclidean Distance Raster?

I am trying to create an attribute table from an Euclidean Distance Raster. I get the following error: "error 000423: Only single band integer dataset is a valid input". The ED Raster has actually the ...
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31 views

How to resample a raster by defined value?

I have got an Euclidean Distance Raster and I need to resample it. I work for a security company and I need a map with the camera resolution (pix/m) in every point of the map covered by a camera. What ...
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2answers
75 views

Calculating average raster to point distances within census tracts

I have some experience using ArcGIS, but mostly with the field calculator in the attribute table/spatial joins, so I apologize if I say something that doesn't make sense. To provide a bit of ...
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1answer
39 views

Performing unweighted overlay on multiple raster layers

Is there a simple process in ArcMap v10.2 that will allow me to overlay three raster images, whereby any obscured pixels will be deleted in the output file? I do not want to retain the values of any ...
2
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28 views

How to create raster from table containing cell values in PostGIS?

I am having a table with integer values. These values are in between 0 and 2. I want to create a raster out of that table with integers as cell values. Or else how to create polygons out of that table ...
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1answer
20 views

QGIS clipper problem when mask used

I have encountered a problem with the raster>extraction>clipper function in QGIS when a mask layer is used. In the image below the diagram on the left shows part of the original raster. The diagram ...
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1answer
21 views

QGIS: Delete information from rasters and shapes that are out of country borders [duplicate]

I am trying to make topographic maps for some countries and show only those countries. I already created reliefs from SRTM-data and imported lake and river data from Natural Earth. Now I want to ...
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12 views

Panel plotting of raster images

I have never used panel plotting for raster images in TIFF format. Any ideas what would be a better module/library to panel plot raster images with examples?
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2answers
27 views

Combine multiple binary rasters to a single raster

I have 5 different species richness maps which I am trying to join in order to show one cohesive map. Each species raster layer has values of 1 and 0; 1 if the species lives there and 0 if the species ...
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1answer
33 views

Rasterize gives weird image

ro<-readShapeSpatial("roads") ra<-readShapeSpatial("railways") co<-readShapeSpatial("LIE_adm0") u<-union(union(extent(ro),extent(ra)),extent(co)) rast<-raster(u,res=1) ...
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26 views

Landsat Data to Map Slums in India

I am working on a project to answer the following geographic question: How much have slum areas increased in Mumbai, India, since the 1970's (or earliest data). I have downloaded LandSat imagery and ...
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1answer
35 views

Determine value nearest to given coordinates [duplicate]

I'm new to GIS and have a very simple question. I have a raster that specifies the geographical distribution of temperature. I would like to find the temperature that is closest to a particular set of ...
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2answers
40 views

Mosaic to new raster: same number of bands issue

I am trying to mosaic 32 raster files (min value 0, max value 13) into one raster file so that I can later use this new raster to extract multiple values to points. However, when I try and mosaic the ...
2
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2answers
48 views

QGIS error when importing .asc LIDAR data

First let me say that I am novice in GIS department. As archaeologist I had only some courses 8 years back when i was still studying. Now, the problem: When I try to import .asc as raster layer I ...
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2answers
41 views

Can the maximum and minimum values of raster display be changed automatically when changing the data frame extents?

I have a raster layer in arcgis which covers a large surface area. I would like to be able to zoom into specific areas of this raster and have it display only the range of values in the area I have ...
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46 views

How to avoid “Unable to compute a transformation between pixel/line”?

I am trying to re-project from Equi-rectangular to the NASA global EASE grid (Equal Area Scalable Earth) grid 1383 586 with a ~25 km cylindrical projection (ESPG=3410). The file is provided as HDF5. ...
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1answer
42 views

creating a random gdal raster with random predefined values

So far I have developed the below code but for some reason it only works for say one class of landuse instead of two. Would you please tell me where I have gone wrong? Thanks so much import os, ...
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1answer
25 views

Clipping rasters

We are clipping one raster to another and our teacher gave us this hint for the 2nd parameter "Remember that the Describe function returns an object. The Clip tool will need the string representation ...
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21 views

Where to find QGIS geoprocessing results?

Is there a way to access in QGIS 2.6.1 something like the Geoprocessing Results window found in ArcGIS? The History and Log window in QGIS appears to show the geoprocessing results from SAGA, OTB ...
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16 views

QGIS - r.* commands not found

I'm very new to GIS and have recently installed QGIS on my mac desktop computer, running Yosemite 10.10. I'm working with DEM data for stream network extraction, but the majority of grass raster ...
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1answer
19 views

Querying Raster Dataset by Location to Study Area

I have downloaded a very handy raster dataset generated by the Nature Conservancy for identifying terrestrial habitat cover types in the north east. Link to the project info and a link containing a ...
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2answers
48 views

How to compute layer by layer after stack?

I have some rasters that I want to compute the moving average and then rewrite the rasters again. r1 <- r2 <- r3 <- r4 <- r5 <- r6 <- raster(nrows=10, ncols=10); r1 <- ...
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28 views

multiply a rang of values in a floating raster to a constant

I have a floating raster layer. I want to multiply a rang of its values to a constant. So, I used the "Con" tool in map algebra with the following script. Con(("Extract_rast1" >= 0) & ...
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29 views

How to re-grid a raster using area-overlap weighted averaging?

I have two rasters r and r2 with different resolutions. I want to re-sample (re-grid) r2 to be the same as r using area-overlap weighted averaging:If an r grid cell is covered by more than 1 ...
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28 views

How to OCR topographic maps

I have old topographic maps that i have scanned and converted into pdf in Actobat XI 11. I need this pdf to be text-searchable (not mere image). To do this i tried text recognition in acrobat but it ...
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30 views

Importing raster from ArcMap to Adobe?

I am currently working with 3 data frames in ArcMap. I exported them to pdf then Adobe Illustrator. I noticed that 2 of the data frames that include rasters come up with striped layers on them (while ...
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1answer
45 views

Extract values from raster by using polygons

I am working with multiple raster files that cover all of united states. The file format of the rasters - GeoTIFF. I have around 100 geotiffs that I need to process. Then I have another shapefile with ...
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35 views

Clipping raster out of polygon using ArcGIS Desktop?

I'm kind of a noob to the GIS programs, and I'm trying to create a map in ArcMap 10. I have a polygon which I manually created in Google Earth and then imported to ArcMap with the KML-Layer tool). I ...
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23 views

How to add a plot with a different x axis to an existing plot?

I am plotting a raster but I want combine to things in the same plot but in two different axis. library (raster) r <- raster(nrows=10, ncols=10);r <- setValues(r, 1:ncell(r)) extent(r) = ...
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18 views

Questions on raster math using ArcObjects

BACKGROUND INFORMATION: I'm using the 10.2 .NET API and what we are doing is this: I have a boat moving on the water at a cruising speed of 30 nm/hr. (and we don't care about currents affecting the ...
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Python Script to iterate numerous, single-band rasters for arcpy.CompositeBands

I have a large collection of single-band geotiffs (NIR, Green, and Red) that I would like to composite using a Python script. The goal is to iterate through multiple folders in a main directory, ...
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10 views

merge rasters using mosaic to new raster - wrong output

I am attempting to merge two raster datasets into one output dataset. I am using the Mosaic to New Raster tool. Unfortunately, the output does not display the same categories as the original input ...
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36 views

QGIS - quickly style categorical map

Example situation: a raster map that denotes various provinces in a country, each indicated with a unique value. Goal/question: quickly (for 'preview' purposes, not making a publishable map) assign ...
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19 views

Calculating Autocorrelation in Different Zones

I'm an intermediate-ish user of ArcGIS 10.2 (win7 pro, hardware robust enough to handle very large datasets and computationally intensive analysis) with perhaps a simple problem that's evading me ...
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3answers
35 views

Counting number of Raster Cells satisfying a criteria within a Polygon

I have a USA raster dataset, which assigns to each cell a value from 0-100. I also happen to have a USA county shapefile. I simply want a count of the number of pixels/cells in the raster data with ...