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

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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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3answers
315 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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1answer
398 views

How to update raster color ramp with new min/max values using PyQGIS?

I'm trying to update a single band psuedo color renderer with new min/max values from the python console. All the code samples i have been able to find deal with constructing a renderer from scratch, ...
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2answers
441 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
101 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") wetb<-...
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1answer
154 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
42 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
84 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
279 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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1answer
82 views

Create a World File from bounding box

What is the most pythonic way to create a Word File for a .png image, having only it's bounding box? For example, given the following bounding box: <LatLonBox> <north>30.46370000000000&...
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3answers
10k views

Writing numpy array to raster file

I'm new to GIS, and I'm lost with something I feel ought to be relatively simple. I have some code that converts infrared images of Mars into thermal inertia maps, which are then stored as 2D numpy ...
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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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1answer
2k views

Are there any general rules of thumb for selecting a transformation for Georeferencing?

There are several transformations that can be used when georeferencing a raster: 1st order Polynomial (affine) 2nd order Polynomial 3rd order Polynomial Spline... etc Are there any specific rules ...
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1answer
11k 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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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
3k views

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
3k views

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
262 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
2k views

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: AAIGrid/Arc/...
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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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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
2k views

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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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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3answers
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Extract Raster from Raster using Polygon shapefile in R

I am new to R and using the raster package. I have a problem extracting polygons from an existing raster file. If I use extract(raster, poly_shape) function on the raster it always creates a list ...
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3answers
14k views

Differences between Raster Dataset, Raster Catalog, and Raster Mosaic

I have about 40 scanned, colorful Geology maps that are GeoTiffs. I want to bring them into an Esri FileGeodatabase to lower their size, combine them as one and display them with a mostly transparent ...
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4answers
3k 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
11k 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 ...
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6answers
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Rasterfile clipping error: Cannot compute bounding box of cutline

I have a raster file and want to clip it, a vector file is supposed to be the mask layer. I use the most obvious method (Raster->Extraction->Clipper). No matter what I do, I get this error (see pic): ...
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3answers
2k views

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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338 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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7answers
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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 ...
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3answers
4k views

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
3k views

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
3k views

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
7k views

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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797 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
1k views

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 ...
11
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2answers
5k views

Aggregating points to grid using R

I have a question with regard to spatial aggregation in R. What I am trying to do is aggregate a point dataset to a grid. I am unsure however how to do this as I have little experience with this sort ...
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3answers
3k views

R: Download a large DEM, change projection, and adjust to smaller scale

This is a process that takes just a few seconds in GIS software. My attempt to do it in R uses a large amount of memory then fails. Is there something wrong in my code, or is this just something R ...
9
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1answer
3k views

Smoothing raster features into polygon

I have raster data representing urbanized areas, which I'd like to trace and convert to a polygon. Using ArcMap's Raster to Polygon tool, I'm able to get something close to that. Unsimplified: ...
9
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3answers
519 views

R, rasterVis and RGL: how to prevent reflective surfaces?

I have been experimenting with digital terrain model files in ESRI ASCII grid raster format. Despite zero experience with this type of data I found it very easy to load into R, as per code below. The ...
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5answers
1k views

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
5k views

How to get hypsometric curve from elevation data?

I have my elevation data but cannot make an attribute table from it and so I'm not sure how to get any of that data into a table in order to make a hypsometric curve.
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1answer
111k views

What is the difference between Vector and Raster data models? [duplicate]

From: http://support.esri.com/en/knowledgebase/GISDictionary/term/vector%20data%20model vector data model: [data models] A representation of the world using points, lines, and polygons. Vector ...
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2answers
13k views

Manipulate .asc files in qgis

I have an .asc file and I want to import in QGIS. The standard way to open it is from "add Raster layer" ("import Raster Layer"), there is another way? I know is strange that ask but I need it. And I ...
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2answers
207 views

Transforming geostationary satellite image to lon/lat

The ICARE Data and Services Center distributes the SEV_AERUS-AEROSOL-D3 product in HDF5 format (http://www.icare.univ-lille1.fr/archive/?dir=GEO/MSG+0000/SEV_AERUS-AEROSOL-D3.v1.03/). The main ...
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5answers
2k views

Is there a way to clip an image with the basic ArcView package (9.3)?

Is there a way to trim a geo-referenced air photo to an irregularly shaped boundary? I tried the clip tool shown in my attachment, but it didn't work. It looks as though the output extent field ...
6
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2answers
2k views

creating a raster of the residuals of a regression between two rasters

I am trying to create a raster of the residuals of a regression between two rasters. i.e. I would like to carry out a regression of one raster against another of the same extent and plot the residual ...
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2answers
749 views

How to decide how to “stretch” raster imagery?

I have to symbolize a digital elevation model. ArcMap offers many different setting for stretching the symbology which all give widely different results. Some stretch methods symbolize the data so ...