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

learn more… | top users | synonyms

3
votes
1answer
1k views

How to Calculate Utilization Distribution Overlap Index (UDOI) in ArcGIS Desktop?

I was wondering if any of you happen to have any information on how to calculate the Utilization Distribution Overlap Index (UDOI) in ArcGIS 10? If I understand it correctly the UDOI takes two kernel ...
3
votes
2answers
325 views

Determine density or cover from a raster layer that has been clipped by a polygon

I am a very new GIS user using ArcMap 10. I have a raster layer of tree canopy that I have clipped so that the layer is in a polygon that is a circle with a 2km radius. I have done this for four ...
3
votes
3answers
3k views

How to get values of each cell in raster attribute table?

How do I get the values of each cell in the raster attribute table. Usually the attribute table gives you the value and number of counts. But, in my case I want each cell listed and corresponding cell ...
3
votes
1answer
558 views

How does cost allocation work?

Why, when I use the cost allocation function of Spatial Analyst, is space not allocated in all input source locations (as shown in image below)? In particular, the input raster has 18 spots while the ...
2
votes
2answers
443 views

Reclassify rasters using GDAL and Python

Using @SS_Rebelious very useful answer, I am trying to reclassify rasters using GDAL and Python. I have a grayscale raster (with values ranging from 0 to 255) and I want to reclassify it to a binary ...
2
votes
2answers
126 views

How to translate (reposition) a .tif raster layer?

I'm starting to use QGIS for my thesis (environmental physics) and have to admit I'm pretty ignorant about it - I've always used Mathematica or Matlab. My problem is: I have a raster layer, in .tif ...
2
votes
1answer
371 views

How can I dynamically trim the informational border off of FAA sectional raster charts?

I'm trying to write a script that can automatically use GDAL to crop the informational border from the FAA's published sectional charts (GeoTIFF) found here: I know that I can use gdal_translate ...
2
votes
1answer
2k views

Raster Version of Spatial Join (one to many) [duplicate]

I have two raster layers that are identical in shape (they overlap exactly) and I need to perform the raster equivalent of a Spatial Join (one to many). My files need to stay in raster format ...
2
votes
1answer
346 views

Raster as Attribute Field Error

I'm using Arc 10.1. I am creating a parcel inventory where I would like to have a photo of the property attached as an attribute and view-able with an HTML popup. I have a polygon feature class built ...
2
votes
2answers
841 views

Conditional combining of multiple rasters to produce one output using Python?

I have two rasters for same spatial extent and need to compare both rasters cell by cell and produce one output raster. Each has 10 land cover classes. Based on those 10 classes the comparison should ...
7
votes
2answers
3k views

How to change null values raster values to 0 in QGIS?

I need help... I'm having problems with QGIS. I have some rasters that appear to have null values, even though I reclassified them to obtain a boolean raster :( How can I change the NULL values to 0?
7
votes
1answer
189 views

Finding largest number of observations within a given radius

I have the following problem: Given the location of insured properties (say houses with fire insurance), i have to find the largest sum of insured values which fit into a 300m radius. Now, my first ...
6
votes
3answers
1k views

How do I extract a raster's extent in python?

I am looking for an easy way to extract a raster's extent in python. Currently, I am using gdalinfo and then parsing out the corner coordinates. The problem with this approach is that gdalinfo is ...
6
votes
1answer
1k views

Counting NoData values in raster using ArcGIS Desktop?

I have created a raster in ArcGIS Desktop 10 with a large number of holes (NoData) in it. I want to fill the holes using something like the the following: rOut = ...
5
votes
1answer
532 views

Creating field with specified slope projecting from 3D polygon?

I am trying to figure out how to create a elevation raster from a known location (3D polygon) that projects at a specified slope (1%) for a specified distance(1-2 km). Does anyone have any idea how ...
5
votes
2answers
5k views

Convert x, y position in georeferenced image (with world file) to longitude, latitude?

What steps do I need to do in order to calculate longitude and latitude for a specific pixel in a georeferenced image? For example this image ...
4
votes
2answers
880 views

Is there a Focal Statistics (spatial analyst) tool in ArcGIS equivalent in QGIS?

I'm attempting to use QGIS v2.0.1 to accomplish the same tasks that I can do using ArcMap v10.1 and I'm running into some trouble finding equivalent tools. In ArcMap I am using the Focal Statistics ...
4
votes
1answer
2k views

Can I access a raster attribute table in QGIS?

I have some Python code that makes Raster Attribute Tables for GeoTiffs using GDAL. In ArcGIS I can see these attribute tables fine and they behave how I like (as classifications). But in QGIS the ...
4
votes
2answers
2k views

Simplify Raster Contours ArcGIS 10

Does anybody know a way to simplify a number of contour polylines derived from a raster dataset? I need to generate a map that shows contour polylines at relatively small scale. With the contour ...
4
votes
1answer
555 views

Can you use arcpy.RasterToNumPyArray() to Graph a Raster with matplotlib?

Can you use arcpy.RasterToNumPyArray() to Graph a Raster with matplotlib? I'm looking to graph a raster with X, Y, and Z values in a 3D bar graph. I just can't seem to translate the numpy array to ...
4
votes
2answers
1k views

Translating grid to USGS .dem in C# via GDAL

I am attempting to translate ArcInfo binary grids to USGS DEM format (.dem). I have installed the GDAL .NET bindings thru this build installer. I can get to GDAL in my C# add-in I am working on. ...
3
votes
1answer
781 views

Re-project raster image from Mercator to Equirectangular

I have a raster image of the world map in Mercator projection, square 1:1 format. I want transform the image into an Equirectangular projection accurately. I assumed from my research that GDAL would ...
3
votes
0answers
133 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
votes
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
398 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
3
votes
3answers
791 views

Is there a Raster Equivalent of the Split tool?

I have the DEM of a State in ERDAS Imagine (.img) format. I have a shapefile containing the counties of that state. I want to split the whole raster into DEMs of the individual counties. The counties ...
3
votes
1answer
57 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" ...
3
votes
2answers
4k 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 ...
3
votes
2answers
762 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
votes
1answer
474 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 ...
2
votes
1answer
104 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 ...
2
votes
1answer
77 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 ...
2
votes
3answers
1k views

How to extract one band from a three band raster in ArcMap?

I'm fairly new to ArcGIS and I get into trouble extracting a single band layer from a raster image .img in ArcMap that I want to use after in zonal statistics. So far, all help I found is to do the ...
2
votes
3answers
414 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 ...
2
votes
1answer
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 ...
2
votes
1answer
909 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 ...
1
vote
2answers
94 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 ...
1
vote
1answer
113 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 ...
1
vote
3answers
183 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 ...
1
vote
1answer
2k views

Clip raster layer with *raster* mask layer in QGIS

Given two input layers 1. The clip layer - an arbitrary layer (though in my case it's a float 1 band geotiff) 2. The mask layer - a paletted raster in which every pixel is either NO DATA or a single ...
1
vote
2answers
716 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 ...
1
vote
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. ...
1
vote
2answers
4k views

How to visualize grd files in QGIS?

How to visualize grd files in the software QGIS?
1
vote
1answer
740 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
votes
2answers
82 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 ...
0
votes
1answer
44 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
votes
1answer
33 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 ...
0
votes
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 ...
0
votes
2answers
181 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 ...
24
votes
8answers
2k 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 ...