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

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118 views

Calculating road density in R using kernel density

I have a large (~70MB) shapefile of roads and want to convert this to a raster with road density in each cell. Ideally I'd like to do this in R along with GDAL command line tools if necessary. My ...
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2answers
25 views

Aspect Patch Count

I am using ArcMap to create aspect maps. I want to find the how many different directions the land faces (total aspect patch count) with continuous patches greater than three. So for example I want ...
1
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1answer
32 views

how can I make “weighted sum overlay analysis” in QGIS? Ordered Weighted Averaging manual may be useful

I have weighted raster data converted from polygons with different categories. I have ArcGIS with 3D Analyst extension, unfortunately do not have Spatial Analyst, and I would like to use QGIS to make ...
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0answers
30 views

Point to Raster Converting Result

I had a problem with Point to Raster converting result. I had an Excel file which contains x, y and z values. I wanted to create an individual raster data from classified z values so I planned to use ...
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2answers
118 views

Getting latitude and longitude raster from DEM

Could anyone please provide with a way to calculate latitude and longitude from DEM, for each raster cell? In previous posts about this, I have seen that some suggest calculating lat and long in ...
3
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1answer
72 views

Numbers containing e in ArcGIS?

In ArcGIS when I try to calculate some raster values or statistics, sometimes I get values that contain e, for example: 1.4e6. What does e mean, and how is it interpreted in ArcGIS?
2
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2answers
92 views

Multiply Rasters from two subfolders

I have two subfolders with Rasters named with the same parameters. I am trying to figure out a way to Loop a multiplication of each raster into a folder with its pair of the other subfolder. Looks ...
0
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2answers
46 views

Zonal histogram for each region (row) in a polygon (table) with python script

I have DEM.tif (symbology uses equale interval - 100m) and a polygon file (regions.shp) with many regions (names are defined in 'reg_name' column). I would like to use Zonal Histogram to produce ...
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2answers
112 views

How calculate pixel by pixel the mode (statistic) of multiple rasters (geotiff)?

I have 12 land cover maps, and I would like to calculate the mode to each pixel of the 12 maps (they have the same resolution and dimension). I mean, the final map would be the mode for each pixel of ...
2
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1answer
35 views

Create Raster Surface from Points and Equations in ArcGIS

I want to use point data to create a raster surface which distributes the values over space, as defined by an equation, and NOT by interpolating. I have an equation to describe how the characteristic ...
0
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0answers
25 views

How to avoid a problem of one pixel when doing non-linear regression?

I am ruining a non-linear regression using nlsLM from package:minpack.lm for multiple rasters (pixel by pixel). My initial values may be appropriate for some pixels but not for others.When I run the ...
3
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3answers
166 views

Assigning RGB values from Geotiff image to LiDAR data, using R

I have given a Geotiff image and its corresponding Lidar data (x,y,z) in UTM coordinates. I need to merge the Lidar data with the RGB values from the image. That means, at the end, I need to plot ...
2
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1answer
34 views

How do I count the number of cells which can see each cell in QGIS

For each cell in a DEM I'd like to count the number of cells which can see it (i.e. direct line of sight) - Can anyone explain how to do this in QGIS? Thanks,
3
votes
1answer
97 views

Unsupervised classification in QGIS

I was trying to learn unsupervised classification in QGIS 2.6 following the tutorial video: https://www.youtube.com/watch?v=mI80eENtWSE When trying myself, clicked Run during the process it shows the ...
0
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0answers
45 views

Can't import libraries to rsaga

I get this error when I'm trying to import a raster to RSAGA: > rsaga.import.gdal(paste(rast_name, ".tif", sep=""),"RASTER", env= my_env) Module 'GDAL: Import Raster' not found in SAGA library ...
6
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1answer
111 views

How to perform a non-linear regression pixel by pixel?

Using nlsLM from Package ‘minpack.lm’ is straightforward for a simple example like this: MODEL:y=(exp(a*x+b*z+c)+d)^f x=c(0.5,0.3,0.2,0.4) z=c(0.1,0.6,1,0.9) y=c(0.2,0.3,0.9,0.9) ...
3
votes
2answers
97 views

How to load projection along with raster in R?

Why the operation myraster = raster("test.asc") does not load the associated projection file test.prj located in the same directory as test.asc? Does raster() need a specific argument? It seems ...
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0answers
49 views

Add Rasters to a new GDB/Mosaic Dataset in ArcGIS ModelBuilder

I'm attempting to add rasters to a new mosaic dataset in a new file geodatabase, all in the same model. However, the Add Rasters To Mosaic Dataset tool does not recognize the NewMosaicDataset or the ...
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0answers
17 views

Creating a time series from multiple rasters in ArcGIS

I have 10 rasters (10 yearly averages of data) that I've uploaded into GIS. I would like to do two things: Create a time-series of the values of that raster at one specific point within it. Create a ...
1
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1answer
64 views

Cost Distance interpretation in ArcGIS 10.2

I am using the Cost Distance tool in ArcMap 10.2 to find the how far it is to walk to the closest area of green space along the road network in a town. I have a input raster of the location of the ...
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2answers
105 views

How to effectively merge SRTM 1 arc data?

We have around 1800 1 arc-second SRTM tiles (Geotiff). How to effectively merge all the tiles into one single file ? We are thinking about splitting 100 files per folder and merge them together using ...
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0answers
33 views

crop shp file leads to different results for same extent

I cropped a shapefile to a smaller extent (my AOI - area of interest) - to work with a reduced working directory. During my workflow I rasterize the shapefile. Here is my problem: I saved both of my ...
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0answers
59 views

Mosaic to New Raster: Problem with min and max values

I have to combine several DEM rasters into one from this source: http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp, so I use Mosaic to New Raster tool. I set up the tool: 1) I input the rasters (all ...
3
votes
1answer
92 views

Converting worldclim data to 30m resolution

I know that resampling from coarse resolution to fine resolution is bad. Effectively you are making up data. However, if the study area is small are there any other options? Worldclim comes at around ...
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0answers
74 views

QGIS 2.8 Raster Layers Moved [duplicate]

I recently downloaded QGIS 2.8 and opened an existing project in it to check how it handled it and make any changes required. This project includes several raster heatmap layers. My problem is that ...
1
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1answer
54 views

How to make a density map from polygons/rasters (ArcGIS)

I would like to make a density map of grasslands. I have a vector layer of habitat classifications, I would like to a density map of grasslands within a specified radius. My thoughts are to: ...
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51 views

Raster to polygon with RGB composite using Arcgis

I am trying to convert an RGB composite to a shapefile to use with. The raster to polygon function returns with three shapefiles with "grid_code" of the value of each of these three channels. I am ...
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0answers
82 views

ImportError: No module named gdal qgis2.8.1

i am using QGIS 2.8.1 (32 bit) in windows 7). I imported two DEMs and trying to merge (QGIS>Raster>Miscellaneous>Merge)them. Unfortunately it gives me import error as below. Traceback (most recent ...
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1answer
32 views

Add information from polygon to raster in R

I would like to add information from a spatial polygon to a new raster. r <- raster(nrow=10, ncol=10) r[] <- runif(ncell(r)) * 10 xym = matrix(c(0,0,0,45,45,45,45,0),4,2,byrow=T) ## create ...
1
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1answer
40 views

Raster display issue in ArcMap?

A client of ours is having trouble with some raster tiles in ArcMap. They gave me a sample, and I was able to get it looking right with the following workflow: All you have to do is go into each of ...
0
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1answer
35 views

Reduce raster resolution based on cell ratio

I have 2m impervious/non-impervious data. I would like to reduce the resolution to 30m and have the cell value for the 30m data be determined by the ratio or proportion of impervious / non-impervious ...
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28 views

Problem with conversion from raster to polyline (not a single curve)

I have raster file and I need to convert it to line. I used GIS tools Convert Raster to Polyline but the line segment is not straight and it is divided into no of segments, isn't it possible to get ...
1
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1answer
29 views

Performing raster calculation in ArcGIS Desktop?

I have a raster layer with values between 0 and 10. My second layer consists of 0's and 1's. What I need is my first layer, but with 0's or NoData values where my second layer has 1's?
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71 views

Apart from “in-memory” space and physical geodatabase, is there any other method to process raster data?

Using the centroid of the building footprints (tagged residential), I want a count of hydrants within 135m, and a count of hydrants within 270m of every residential footprint. This would be based on a ...
1
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1answer
37 views

Georeference multiple raster layers of same area at once or identically

I have many raster layers that I need to georeference to my existing vector layers. Data types vary between 8 bit unsigned, 32 bit float, and bit 64 float. All have the exact same extent, cell size, ...
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1answer
59 views

Tools for building and exporting high resolution geotiff

I'm having some really nice raster maps in geotiff format. I would like to add some features to these maps as well as then exporting them as tiles for serving the map from a web server. Preferably I ...
2
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1answer
38 views

Georeferencing uneven/irregularly gridded rasters

I'm trying to take a set of NetCDFs and turn them into georeferenced datasets using GDAL. However, the only Geospatial data is a set of 2-D lat/lon arrays. The projection type is not lat/lon. THe ...
2
votes
1answer
42 views

Is there a better way to convert Raster to Point data? Don't need one point for every cell

I need to convert raster data to point data so I can use the points for interpolation via kriging. My problem is that my resolution is 5 ft and I'm working on a whole city. The data I am converting ...
0
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1answer
28 views

QGIS extend raster layers extension

I want to extend a raster layer to another layer's extension (my input raster layer is smaller). The new raster cells should have 0 value. Is this possible in QGIS?
1
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1answer
23 views

Raster layer - changing values in raster cells

I have a lot of cells in a raster layer (GeoTIFF) with a -9999 value in it. I would like to update that values to 0. I mean, in vectorial layers would be something like: CASE WHEN band1=-9999 THEN 0 ...
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0answers
22 views

QGIS Rasters - Filling no data cells [duplicate]

When making a sum between two raster layers, for every cell, if one of the two cells have no data in that cell, the opeartion is not done in that cell, example: In QGIS raster calculator I do: ...
0
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1answer
26 views

White Pixel in Raster (CIR) arcmap 9.3

i have to analyse forest cir orthophotos. in high scale resolution, many white pixel appear instead of red ones. i work with arcmap 9.3, win7
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1answer
32 views

QGIS Raster Calculator, joining two raster

In QGIS raster calculator I do: Plus (+) And I get: The red circle in the middle is like cut in the result, QGIS it's not adding every pixel on each raster, it makes a kind of ...
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0answers
22 views

How do you symbolise a 32-bit raster in ArcObjects?

For rasters that are ABOVE 16-bit - you cannot apply a colormap - so what is happening when you symbolise in ArcMap a 32 bit raster, it's certainly possible. I'm trying to emulate this funcitonality ...
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1answer
32 views

Clipping a raster layer with a shapefile on mac

I am trying to clip a raster layer using the raster clipper function. However, for some reason this is not working for me and I haven't been able to find the answer anywhere. I choose my raster ...
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1answer
68 views

Use raster memory layer from QGIS processing result

I want to apply subsequent QGIS raster processing algorithms in a python script. I want to use memory layers for intermediate calculation results since I am only interested in the end result. As ...
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0answers
17 views

How to import Esri Raster to IDRISI with NoData value?

I made some point features in ArcGIS Desktop to build training samples to import to IDRISI. I had 7 classes and convert the feature to raster to build the signature in IDRISI. When I import the data ...
0
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1answer
88 views

Import GeoTIFF into MapInfo - why “control points”, and how to batch-create TAB files?

OK, so I am largely hostile to commercial software with 'proprietary' formats, but a colleague only knows MapInfo. I have a bunch of GeoTIFFs (produced by gdal-merge of JPG/JGW-filepair hi-res aerial ...
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19 views

Aligning to DEM after TIFF conversion to GRID?

I can convert a TIFF (NASS Cropscape) by using Create Raster in my .gdb or Export to other Format. However, all efforts to align the extent to an existing DEM have escaped me! I have tried Snap ...
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1answer
76 views

ArcGIS error: Unable to save edits. Raster dataset already exists

When I edit my attribute table then try to save edits an error message appears on my screen: "Unable to save edits. Raster dataset already exist." Why does this error message appear? My table of ...