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

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Replacing raster values in one raster with another raster in QGIS … how to?

I have a raster (DEM) and want to replace a few cell's values with the values from another raster in QGIS. I would have done this with the "over" tool in the raster calculator in ArcGIS. Specifics: ...
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2answers
714 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
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Creating spatially projected polygon grid with ArcMap

i need to create a grid with 1x1 square kilometres cells in ArcMap. The operation located in Data Management Tools -> Feature Class -> Create Net is almost what i need but in the parameters, i can't ...
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1answer
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How to create attribute table for raster data?

I have raster dataset for rainfall but its not having attribute table. How can I create tabular data using the same raster file? How to join it back again to it? Software used is ArcMap 10.1.
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2answers
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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
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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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2answers
7k views

How to visualize grd files in QGIS?

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

Writing Python script tool to enable ModelBuilder to skip over rasters without data?

This modelbuilder works well until the raster to polygon step. At that step, rasters without features cause an error(error 010151). I would like to put in a step before raster to polygon that causes ...
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2answers
59 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
515 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
298 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
300 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
453 views

Read layer symbology class color with ArcPy

I am using ArcPy within ArcGIS 10.1 and attempting to read symbology from a *.lyr file created by a raster dataset within ArcMap. My goal is to be able read out the RGB (color) values assigned to the ...
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3answers
2k views

How to make polygon from cells of a raster?

I have 100 rasters, each raster has the same cell size and extent and i want to make a polygon of each cell. Can anyone help me doing this?
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1answer
878 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 ...
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1answer
36 views

Intersection of a raster and polygon in ArcGIS 10.3

I have two data sets one raster and one polygon. I am interested to see learning the area where the two overlap. I was thinking that I could use the intersect function, but since one of the layers are ...
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2answers
66 views

ArcGIS Multiband Raster

I know this has been asked and answered here but since I don't have enough rep to ask a clarifying question to the person who answered it I am having to post a completely different question. I am ...
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1answer
84 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
138 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
547 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 ...
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1answer
141 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 ...
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1answer
53 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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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
389 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 ...
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1answer
269 views

Clipping Rasters with a mask layer error

I've got a NDVI layer that I'm trying to clip with a vector file but when I try and use GDAL Tools clipper I get an error. That shows up like this: What am I doing wrong? This is before I even pick ...
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2answers
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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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1answer
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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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3answers
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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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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
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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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1answer
222 views

Displaying numbers of single band raster layer in QGIS without additional vector layer?

I wonder if there is a raster symbolizer in QGIS with a label option, that renders the cell values as labels of single band raster layer, a scalar field. The standard raster symbolizer dialog in ...
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2answers
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Generating contours from DEM using GDAL?

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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3answers
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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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4answers
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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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4answers
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Looking for a fast, open-source raster cost-distance function to use in code

I've been scouring the internet for a fast, open-source cost-distance function that I can embed inside my code. The functionality should basically work like the ArcGIS implementation where I can ...
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1answer
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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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3answers
4k 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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4answers
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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
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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 ...
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3answers
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How to speed up queries for raster databases?

I have a raster database in postgresql/postgis with these columns: (ID, rast, data_of_data). 'rast' is the column that has raster files in WKT format. An example query to find the DN value of a ...
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2answers
334 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?
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4answers
500 views

How to compare areas in scanned historical land use maps

I am a relative beginner to using GIS, and am running QGIS 2.0.1 in Linux. I have two historical maps which I want to analyze, that show land use patterns in the same area at two different moments in ...
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7answers
3k views

how to overlay shapefile and raster?

I have a shapefile with polygons. And I have a global raster file. I want to overlay the shapefile's polygons onto the raster grid and calculate the mean raster value for each polygon. How can I do ...
9
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3answers
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Make the nodata area of a resampled orthophoto overview white?

I have a set of orthophoto images which are each fully filled with data, but when placed together the coverage does not form a rectangle so there are nodata areas. In MapGuide, I need to be able to ...
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3answers
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Poor image quality of raster pyramid files in ArcGIS Desktop (no anti-aliasing)?

There are several GeoTIFF files (size ~7000x7000 px) which I try to open in ArcGIS Desktop 10.0. I have already created raster pyramids for them (.ovr files) using geoprocessing tool but their quality ...
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2answers
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QGIS and Raster Mapping in 'Seamless' layer

I would like to use Ordnance Survey base mapping in QGIS. I would like to set up something like a seamless table in MapInfo. I think that the equivalent in QGIS is a Virtual Raster Table. The files ...
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3answers
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How to make transparent the background of a topographic map in QGis 1.8.0?

I'm starting to use QGis 1.8.0. I have a raster topographic map, i.e. white background and black contour lines, houses, roads and so on. I want to make transparent the white background, so if I ...
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2answers
764 views

focal statistics with variable radius

is there an easy way to do focal statistics on a raster, with a variable radius for the neighbourhood to be searched? As in: that search radius would be stored in another raster? i tried something ...
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3answers
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Web mapping software for a huge raster time series?

I'm an ArcGIS Desktop user who is stepping into the world of web mapping for the first time. Following advice I found here on GIS.SE, I started with the free tutorials from OpenGeo. However, I ...