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

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191 views

Reprojecting a raster image using gdalwarp

I am trying to reproject an ECW Orthophoto from 25830 to 23030 srid. I tried the following but I am getting an error: C:\Program Files (x86)\FWTools2.4.7>gdalwarp -s_srs 25830 -t_srs 23030 ...
3
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1answer
86 views

What is the replacement for 'setColorShadingAlgorithm' in QGIS 2.6?

I have been struggling with setting the colorshadingalgorithm for a raster layer in QGIS with no success for the past few days. The QGIS cookbook seems to be pretty outdated. Anyways, the code that I ...
3
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2answers
261 views

Display two-dimensional color gradient for two different quantities

I have two overlapping raster layers. One contains quantity A from 0 to 100, and the other contains quantity B from 0 to 100. I'd like to create a map displaying both sets of data at once based on a ...
3
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0answers
146 views

How to compute surface of raster or any point using ARCGIS?

I have a raster image whose values are a digital elevation model of terrain. I need to know the surface type (topographic characterization) of particular points along transects of this DEM. How to ...
3
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4answers
2k views

Clip a raster using a shapefile into multiple rasters?

I have a raster file representing a large area and a shapefile of 30 polygons representing watersheds. I would like to clip the raster with the shapefile to create 30 rasters representing each ...
3
votes
1answer
528 views

NOAA Nautical Charts .bsb format

Is it possible to load a nautical chart from NOAA into QGIS that has the .bsb format? Didn't have much luck with mrSID format. using QGIS(dev) on ubuntu 13.04
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2answers
939 views

Round Raster to next higher or lower int

I am using ArcGIS 10.1. I am searching for a solution to calculate a raster. The values are like: 0.2 0.6 5.3 i.e. How can I now get 0.2 as 0 and 0.6 to 1 and 5.3 to 5? In the end integer numbers. ...
3
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1answer
59 views

How to always see all band values with Identify Features of QGIS?

Does anyone know if it is possible to get the Identify Features tool in QGIS to show the band values for all the layers shown in the results window? To clarify, whilst I have several bands "showing" ...
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2answers
5k views

How to export a raster layer for external processing?

Is there a way to export all values from a raster to for example a cvs or other textfile or dbf or xls and later import (changed) values from that file back into the raster? For vector-files this is ...
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5answers
3k views

Adding Raster Layer without lyr file using ArcPy?

i wonder how i can add a raster layer to a remote (not the current) mxd file with arcpy. I need to not use a lyr file for that. For vector Layer i have the following lines working fine : mxdPath = ...
3
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2answers
787 views

Overlaying GPX data on rasters in QGIS

I have a series of raster map images that I would like to use in QGIS and overlay some simple GPX routes over the top to produce a custom map image. This is all quite new to me so please bare with ...
3
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1answer
527 views

How to get the Flow or directional raster map using GRASS?

Aside from using r.fill.dir in GRASS, is this the script to produce the Flow or directional raster map? Is this the output for the script ...
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1answer
141 views

Is it possible to read raster files by block with rasterio?

I find rasterio much easier to use that plain ogr/gdal, so I'd prefer using it. However, I need to process large rasters, so reading rasters by block as explained in the Python GDAL course is ...
2
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1answer
137 views

Build raster with multiple attributes based on 3 input rasters

I am trying to make a new raster based on three input rasters which have the same cell size and the grids align perfectly. I now want to construct a new raster, which for each cell, has three ...
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3answers
408 views

Rasterize line shapefile

I'm trying to convert a line shapefile to a raster image at QGis, but my attempts have been unsuccessful. I've tried to use Raster/Conversion/Rasterize and SAGA/Grid - gridding/Shapes to grid, but to ...
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2answers
515 views

Automating the production of GPS-compatible map tiles from georeferenced raster maps

I have a set of TIFF maps that I want to load onto Garmin GPS 62s units. The maximum size for each tile on the GPS is 3Mb and less than 1 million pixels. I manually produced one tile, following this ...
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3answers
494 views

Raster map in different zone () than region ()

I am new to QGIS (just installed QGIS 2.0.1) and am having problems running any spatial analysis tools. I followed the instructions on how to call GRASS tools into QGIS, but when I try to run the ...
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2answers
1k views

Arcmap 10 restrict Flow Accumulation

I am working with the Flow Accumulation tool in ArcMap 10's spatial analyst hydrology tools. This tool calculates the total number of raster cells that flow into a given cell. However, for my ...
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2answers
1k views

How to calculate volume from a raster file?

I have a raster file containing the depth of water. I need to find the volume of water using that raster file. I need to find the area of each cell and multiply with the depth. How can I do it in ...
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1answer
1k views

Filtering a raster by pixel value ? (Qgis)

I have downloaded Globcover data in GeoTIFF format. I want to create a new grid which only has values where the Globcover data (the only band in the TIF file) has one certain value (==190). Can I do ...
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2answers
43 views

Create a raster with ranges from another raster

I have a raster that contains values ranging from 1-180. I am looking for a way to create a new raster where if the values of a cell in the original raster is between 1-10 the new raster cell gets the ...
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2answers
222 views

Prepare raster data for wms using geoserver!

I have some orthophoto of different resolution (urban 8cm pixel, hill 20cm pixel, mountain 35 cm pixel) which cover an area of 28000 km2. Those are in jpg format, already georeferenced. I need to ...
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1answer
159 views

GeoTIFF created using ArcGIS for Desktop not displaying in Google Earth or Photoshop?

I originally had an IMAGINE Land Cover raster file that I opened in ArcMap. I used the Extract Feature from Raster to extract only the Developed class and saved it (still IMAGINE). Then I used the ...
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3answers
221 views

What is the math behind rasterization?

I'm taking the first steps in QGIS (version 2.2 Valmiera) and I am having some difficulties in knowing what mathematical criterion that QGIS uses when converting polygons (shapefile) to raster. I'm ...
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2answers
976 views

How to clip an Openlayers OSM Background to a Vector Boundary?

I'm new to QGIS. In my project i have two layers: one is my vector (city boundaries) and the other is the OSM (obtained with the plugin). How can I cut the OSM along the edges of the vector? I want to ...
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3answers
3k views

QGIS Raster Calculater Syntax

I am trying to use the raster calculator in QGIS to combine a number of rasters. I want to calculate a mean, this is easy: (raster_1@1 + raster_2@1 + raster_3@1) / 3 I then want to create a max. ...
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2answers
5k views

How to visualize grd files in QGIS?

How to visualize grd files in the software QGIS?
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1answer
798 views

1-band raster colour table workaround in QGIS

Does anyone know what the workarounds are for the 1-band raster colour table plugin in QGIS? Currently I find it will run once, then crash on the second iteration. The workaround I use is to delete ...
0
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1answer
54 views

How to rasterize a vector dataset in R?

I would like to compare vector vs raster data. So i try to fix a problem using both ways. I made it in vector first : coastline<-readShapeSpatial("shp") wets<-readShapeSpatial("shp") ...
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2answers
57 views

Hosting Rasters as a Tile Server

I am currently trying to serve a Raster Datasheet made from several Geo(TIFF) files but I am unsure about how to go about it as I'm quite new to GIS! I need to host it online so that clients can ...
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2answers
144 views

After turning census block data into a raster, how do I redistribute the density to reflect land cover types

I plan on rasterizing (terminology?) census block data relating to density to a regular 30 m by 30 m grid for use with NLCD data. I then hope to distribute the density of the original census block ...
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2answers
282 views

Getting latitude and longitude raster from DEM using ArcGIS for Desktop?

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 ...
0
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1answer
71 views

How to import Ordnance Survery raster layer to ArcGIS Desktop?

I have downloaded raster map data from ONS, the data has come in the form of two files... one is full of .tlw files and the other is full of .tab files... How do I import it into a raster layer to ...
0
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1answer
39 views

Got different cell sizes from a rasterised data

I'm trying to rasterize the Land cover data of Nigeria which was obtained from FAO database. During the process of rasterizing the land cover data, I used the following information which gave ...
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0answers
53 views

Publish rasters stored in PostGreSQL with GeoServer [duplicate]

we are trying to publish some raster images stored in our Postgres database. First, they were generated from satellite images (spectral indexes). Then we uploaded them with raster2psql as tables. So ...
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2answers
250 views

How can I fix a geoTiff with an incorrect CRS?

Trying to load and plot a raster (it's a DEM) in R, but having problems. Using R I read in a raster file: library(raster) dem <- raster("DEM_Victoria.tif") # >70 MB print(dem) class ...
11
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1answer
7k views

Raster legend in R: how to colour specific values?

I have an elevation model plotted in R r <- raster("example.dem") plot(r, col = topo.colors(20)) Some of the values are below sea level (0), and I'd like to have those display in red. How can ...
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8answers
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What raster-based GIS systems really work?

Raster GISes like GRASS, ArcGIS/Spatial Analyst, and Idrisi can perform a rich set of data processing and analytical procedures loosely known as "map algebra." In today's computing environment it is ...
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6answers
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How do I iterate through every cell in a continuous raster?

See this link for more details. The Problem: I want to loop through a continuous raster (one that has no attribute table), cell by cell, and get the value of the cell. I want to take those values ...
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5answers
2k views

Multicriteria Analysis : how to?

I have to do a multi-criteria analysis to answer the question : "which is the best lot to develop". A few of the criterias are : distance of the nearest bus stop (point layer with bus stops) ...
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2answers
1k views

Resample binary raster to give *proportion* within new cell window

I would like to go from a binary raster of forest/non-forest at 30m resolution to a raster at 240m resolution with the value of each cell being the proportion of that cell forested - i.e. the data ...
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3answers
842 views

How to extract breaklines from a given DEM?

Breaklines are very useful for describing a terrain - for example to build an exact TIN. My question is, how to extract these breaklines from a given DEM? I calculated the curvature (vertical) - ...
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2answers
1k views

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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3answers
3k views

How to efficiently read and reclassify many rasters in R

I've been tasked to create a suitability analysis of wave conditions in the Gulf of Mexico. I have 2 thousand or so raster files that are about 8 MB each (2438 columns, 1749 rows, 1km cell size). ...
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2answers
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Good practice for generating contours from a DEM

We have just received a large set of DEMs at work and I would like to generate contours from them. The DEMs have a resolution of 1m and a size of 1kmx1km. Output from gdalinfo: Driver: ...
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4answers
1k views

Problems with NA values when reading .DEM file with R 'raster' package in Windows

I am trying to read a raster file in a .DEM format on windows using the 'raster' package in R. I get problems with NA values, when loading the data into R in Windows 7, but I do not have the problem ...
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1answer
4k views

ArcMap 10 - Extract raster cells from imagery based on RGB value

I've got some aerial photography (format: IMAGINE Image) which is detailed enough to see to fire hydrants and a shapefile of fire hydrants which was digitized based on some CAD data. My project is to ...
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4answers
2k views

Where can I find examples of fuzzy logic applications in ArcGIS?

The last ArcGIS version (10) includes two arctoolbox tools for fuzzy logic (Fuzzy Membership, and Fuzzy Overlay). Does anyone know where can I find some examples showing how they can be applied? ...
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4answers
9k views

Loading a raster into a PostGIS 2.0 database on Windows

I'm trying to figure out how to load a raster into a PostGIS2.0 database (I have asked previous questions on this topic here and here). I am trying to use the raster2pgsql.exe program provided with ...
10
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2answers
291 views

Count raster value in a bounding box (spatial extent)

I have simple question: given a bounding box, how can I count the number of specific values (say, I am interested in the number of value == 1 ) in a raster in 1) arcpy, or 2) raster package in R?