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

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Determine changes in land cover of isolated features over time?

I have a a study area of 2 Landsat scenes from 2013 which were classified for a specific natural community, and these areas have been isolated and extracted and digitized into vectors so that they can ...
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2answers
135 views

How do I stop null values from being assigned extreme color values?

I have a raster surface that I kriged in Surfer and imported to Grass GIS but when I view it in QGIS, the null values outside of the interpolated surface take an extreme value and wash out the ...
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1answer
104 views

Merging Raster: ImportError: No module named _gdal_array

When I try to merge rasters I got following error message: _gdal_array = swig_import_helper() File "C:\PROGRA~1\QGISDU~1\apps\Python27\lib\site-packages\osgeo\gdal_array.py", line 18, in ...
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2answers
20 views

Setting background RGB value to invisible for multiple rasters in ArcGIS Desktop?

I'm using ArcGIS Desktop 10.0. I need to set my background rgb value of 255,255,255 to transparent. In the layer-Properties Windows > Symbology I can do it for one layer, but can I batch set this, or ...
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0answers
27 views

How to add a TIF raster layer programmatically?

This is my code whenever i try to load .tif image it shows layer is not valid,QgsRasterLayer always return invalid layer (I am using linux 12.04). QString myFileName = ...
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0answers
22 views

Is it possible to change the default raster style of newly created rasters in QGIS?

If I do calculations on rasters with the raster calculator or other tools, the resulting rasters displayed in my canvas are always in the same default style (singleband gray, black to white...) so ...
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1answer
27 views

how to use gdal_rasterize? how to know which attribute to burn with ogrinfo?

I have a vector layer I need to rasterize. I guess this is a basic operation, but I haven't found the information I need yet. First, I have reprojected the vector shapefile: ogr2ogr -s_srs ...
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2answers
41 views

Is there raster equivalent to vector Intersect?

The intersect tool that is used on vector data cannot be used on raster data. What tool can I use for my two rasters that does the same as the Overlay > Intersect tool?
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4answers
127 views

raster area calculation using python script

Hi I am a beginner to python programming in GIS and am trying to calculate the area of a raster. When I ran the program, I got error message below. I am also providing my code. Any help would be ...
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2answers
587 views

How to convert raster to point in QGIS

I wanted to convert Raster into Point Vector in QGIS. Is it possible? QGIS have option to convert it into polygon but i didn't found any tool to convert it into point. can anyone help me?
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0answers
12 views

How to group a multiple rasters in MapServer?

I had a map files for each state (raster file) of India. Now I want group all mapfiles to show a single raster or single map file? How I can do in using qgis or any platform?.
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26 views

What is the source of horizontal and vertical striping in USGS DEMs?

When processing 30m and 10m DEM data downloaded through the National Map Viewer from the National Elevation Dataset, we noticed horizontal and vertical striping not only in the produced results, but ...
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1answer
31 views

Con() does not recognize raster values

I have a problem when using the con() argument. What I want to do is to remap all raster of a raster file ("Red_SL") cells with values larger than 40 to the new value 5. All other values should be ...
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2answers
40 views

Use Values from Raster Statistics (e.g. sum of all cells) in Raster Calculator

I need to do calculations on raster layers which require the sum of all cells of the raster. I've used the zonal statistics tool for that but it gets a little annoying to do those extra steps (run the ...
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1answer
21 views

Cannot get 2 raster files of same cell size to align ArcMap 10.2

I have two raster files that are the same cell size but I cannot get them to align properly. (I want the black to line up with the pink) When creating the black raster file (from using polyline to ...
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0answers
13 views

Merge/mosaic categorical rasters in QGIS/GDAL

I am attempting to make yearly bins of some monthly MODIS data for all of the US. The cells of the raster are defined with Julian dates indicating the date at which a burn event took place. After ...
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1answer
22 views

Iso Cluster tool in script failing to open clip raster

I have been coding in Python for only a few months, so maybe I'm just overlooking a minor detail as a newbie. I have written the script below for a class project. It is supposed to clip two rasters, ...
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2answers
46 views

QGIS Raster Calculator: Need values to be set to 0 instead of no data

I have a landcover map with different values for the landuse options e.g. 190 for commercially used areas. Now I want to extract only these areas using the Raster Calculator with the expression ...
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0answers
18 views

Problem with adding mosaic layer via arcpy

I have a mosaic layer that I want to add to my map in ArcMap. When I add this layer manually (i.e the "Add Data" button), a raster image, a boundary, and a footprint are added to my table of contents. ...
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1answer
219 views

Build Raster Attribute Table with GDAL Utilities

Is there a way to build a raster attribute table using one of the GDAL utilities? I know you can view it using gdalinfo and I have successfully created one using Python, but it would be so much ...
4
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3answers
408 views

Loading raster data to postgis

I'm a newbie in GIS technology and need some help in loading a rainfall radar raster data into PostGIS. The raster image is shown here: What I need is to store in the database the radar ...
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4answers
269 views

How to export raster from PostGIS enabled DB as GTiff with gdal_translate

When I want to export a GTiff from my PostGIS DB with this code: gdal_translate -of GTiff PG":host='localhost' port:'5432' dbname='landslide' user='postgres' password='pass' schema='public' ...
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1answer
113 views

How to find the projection of an image?

Instead of georeferencing the image and deforming it, I'm trying to find the projection used by the author of the image. I've got tens of these distribution maps to digitize. The idea is to avoid ...
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32 views

How to choose which band is used to calculate DN when converting a raster to vector?

I currently have a raster layer of flood water levels (elevation) which I need to convert to a shapefile for future use. My raster is 4 bands: RGB + one band with values from 0 to 10, representing 10 ...
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1answer
82 views

Map algebra for loop

I have never coded in Python before and I am trying to loop a simple map algebra equation across 365 rasters. I am trying to calculate total water flow over cells but in the raster I have a negative ...
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2answers
83 views

Reading a raster map cells values in C#?

Suppose I have a raster map file (TIFF, TGA, JNG... etc) loaded with geo-info manifested by the cells values. I need to read the values of the raster map cells "programatically" in a C# program. P.S: ...
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3answers
37 views

Use GDAL command line to copy projections

I have two images, a georeferenced Tiff and a second Tiff without a reference. The second image is a copy of the first, but it lost its reference. Now, I want to copy the reference from the first Tiff ...
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1answer
166 views

R raster Package Moran's I interpretation

I am using raster package to calculate the local Moran's I . The example gives the range of Moran's I between - 1 to 2.47. On my own data I have see the value range -3.070423 - 7.228558 How can ...
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1answer
542 views

Problem in importing raster data from PostGIS to Geoserver

I am using Opengeo Suite 3.0.2, PostGIS 2.0.3 and PostgreSQl 9.2. I am trying to import raster data from PostGIS to Geoserver but facing an error. I follow this tutorial link to import the raster ...
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2answers
101 views

Copy Jp2000 from Mosiac Dataset turns white

I am trying to copy a raster to jp2000 from another File Geodatabase that I created as a Mosaic Dataset. It came out as a whiteout in the middle. I don't know what it cause this. See screenshot : ...
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3answers
49 views

Zonal Statistics as Table Tool

I have a slope dataset. I have a polygon shapefile with territory within the extent of the slope map. I have to calculate the real surface area of this shapefile using the zonal statistics as table ...
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how can i obtain mean of 30 bands from the help of raster calculator in QGIS API with python? [on hold]

class BankAccount(object): def __init__(self, initial_balance=0): self.balance = initial_balance def deposit(self, amount): self.balance += amount def withdraw(self, ...
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33 views

Raster Calculator

I have a slope dataset. How do I calculate the real surface area for this slope dataset using the raster calculator. This is the example I was given: orthogonal area of a raster cell in square ...
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1answer
430 views

Create raster distance around a single point feature class

Okay, so I'm relatively new to ArcMap and I'm trying to use the Fuzzy membership for suitability test. I have a single point feature class that I want to use for this analysis. I know that in order to ...
2
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1answer
50 views

data source for worldwide cross-sections of topographic and bathymetric for woodworking art project?

i am a decent r programmer and statistician, i am able to work with data sets pretty well. i am less familiar with GIS tools, but if given a shapefile i can certainly plot political borders and ...
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32 views

Polygonize Missing Polygons

Polygonize is not capturing all of the pixels in an image that has been converted to 0s & 1s. The pics below show -original geotif -geotif recalculated to 0s & 1s -polygonize output As the ...
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10 views

Raster Analysis Grid (Interpolation) Crashes

Upon clicking on "Grid (Interpolation)" QGIS crashes. I running QGIS 2.2.0-Valmiera on a Mac with OS X 10.9.4 Thank you for any trouble shooting guidance
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96 views

How can I see average of raster value over certain area, marked by mouse?

I have a raster in Quantum GIS and I am just exploring it. How can I see average of raster value over certain area, marked by mouse? In other words: How can I select particular area in QGIS? How can ...
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138 views

How to convert a shapefile to binary grid?

I have a polygon shapefile with a UTM projection which I read into MATLAB: s = 'C:\path\to\shapefile.shp' % Read the shapefile shp = shaperead(s); How can I convert this simply polygon into a ...
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5answers
2k views

What is Change Detection and how I can perform such analysis with open source tools?

From wikipedia page: Change detection for GIS (geographical information systems) is a process that measures how the attributes of a particular area have changed between two or more time periods. ...
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2answers
422 views

What is the correct way to convert a USGS Orthoimage from WorldImage format to tiled GeoTiff for GeoServer?

USGS provides different resolution orthoimage quadrangles in the WorldImage format (*.tif with an accompanying *.tfw world file). Some of these quadrangles can be used by GeoServer (2.1.0 - 2.1.2) by ...
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1answer
37 views

Raster Calculator Blurring Image Results

I am trying to run a NDVI analysis using raster calculator on Arg Map 10.2.1 and the results create blurry or bleeding image, almost as if the map has been dipped in water. I am using the default ...
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1answer
156 views

Progress bar percentage is increasing and decreasing, never finishing

I am trying to clip a raster by shapefile perimeter using the Clip tool. The percentage has been jumping between 0% and 100% for over an hour, back and forth, climbing to 100% then dropping down to ...
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1answer
37 views

ERROR 000824 while trying to run IsNull Method outside ArcGIS?

I am trying to perform IsNull function to a raster using PyScripter. This is the code I use: import arcpy import arcinfo InRaster = "C:\\data\InRaster" IsNullRa = "C:\\data\IsNullRa" ...
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22 views

Positioning and tracing polygons over an image

On QGIS 2.0 - I want to add an image (TIFF or whatever) then resize and correctly position it over a satellite image (openlayersplugin). Then, the task is to create a new shape file layer and draw ...
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2answers
25 views

polygon to raster - not all polygons rasterized

I have a building footprint shapefile (polygons) that I want to convert to a raster. I use the Polygon to Raster tool, and specify a cell size by importing from another raster (which is 24m x 30m). ...
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1answer
33 views

QGIS: Need to remove unwanted white bands when raster layer are overlapping

In my project when raster layers are overlapping a white band appears the edge of the top layer. How can I remove it and obtain a seamless overlapping of the raster ? (I have try to built a vrt with ...
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1answer
23 views

R giving error when attempting map algebra

I'm trying to manipulate some downloaded rasters using R, and keep getting the same error when I try to do any type of map algebra. The example below uses a raster file downloaded from ...
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1answer
16 views

QGIS: how to identify a visible raster layer among large view (composition of rasters)?

I have QGIS project loaded with many raster files. For a given area, (ex: under my mouse pointer), I am looking for way to identify which (raster)layer provides the visible data. To start, I will ...
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2answers
41 views

gdal2Tiles output differs from MapTiler

I'm in need to process a large batch of Landsat images with MapTiler and since the version I'm using (1.0 Beta 2) does not support multiple input files, I created a simple python script that calls ...