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

learn more… | top users | synonyms

2
votes
1answer
964 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 ...
0
votes
2answers
272 views

Issues calculating range with QGIS 2.0 raster calculator

I would like to calculate a simple range using the QGIS 2.0 Raster Calculator, but am getting strange results. I believe I am not using the correct syntax. To get all values between .003-.5, I ...
1
vote
1answer
280 views

how can I make “weighted sum overlay analysis” in QGIS? Ordered Weighted Averaging manual may be useful

I have weighted raster data converted from polygons with different categories. I have ArcGIS with 3D Analyst extension, unfortunately do not have Spatial Analyst, and I would like to use QGIS to make ...
3
votes
1answer
32 views

How to combine 2 vector shapes created from raster files

In Qgis 2.12 Lyon, using windows 10 I downloaded 2 raster files from an area of my interest. The rasters were on information about precipitation and evapotranspiration. Each cell had a value. I ...
1
vote
1answer
306 views

How to extract percentage of land cover from a raster according to multiple shapefiles?

I have a raster map that represents land cover of a region, and different shapefiles (total 120) in the same region. I want to know the percentage of every land cover for each shapefile. For example, ...
4
votes
1answer
182 views

How to compute NDSI in ArcGIS for Desktop?

How do I compute a Normalized Difference Snow Index (NDSI) in ArcGIS's Raster Calculator? I have a Landsat 8 scene (hdf4 format) that contains derived surface reflectance band-by-band. Each band is a ...
0
votes
1answer
204 views

Creating an R factor raster in RUSLE Soil Loss equation with multiple input rasters

I am attempting to obtain the rainfall erosivity "R" factor for the RUSLE Soil Loss equation using rainfall PRISM 30 year history data. I have both monthly and annual data that comes into ArcMap as ...
2
votes
0answers
339 views

Create custom pixel block size in ArcGIS 10?

I'm using the new IRawBlocks in ArcGIS 10 from the adopted sample in ArcGIS 10 SDK help and I want to create a custom sized pixel block that feeds me a block of values column by column instead of a ...
2
votes
2answers
1k views

Clip_management to raster extent outputs larger raster than raster extent

Using Python and ArcMap 10.0 SP5, I'm trying to reproject and clip a large input raster to exactly the same grid as a smaller target raster (same extent, pixel sizes and projection). The problem is ...
3
votes
3answers
455 views

Spectral profile (z-profile) viewer for ArcGIS

I have multilayer raster with 6 bands. Is there a way to select one specific pixel and to display the z profile (the values of each band) for this pixel as a chart or table? I am looking for a tool ...
1
vote
0answers
33 views

QGIS polygonize tool not working [closed]

I am having a problem using QGIS ver 2.10.1 Pisa. I am trying to use the polygonize function on a raster .tif image, and it runs, but only produces a thin sliver of polygons at the top, then stops ...
0
votes
1answer
268 views

Combine overlapping rasters in gdal_calc.py, taking the maximum value from each pixel?

I want to combine 3 overlapping rasters to create 1 raster. Each have the same dimensions, resolution and CRS. I want to populate the new raster with the maximum value from each of the layers. ...
0
votes
0answers
8 views

Created raster with not expected range

I have created a raster layer with kriging tool as source of data have localized sapefile attached and shown in Figure. Why the value range and are produced raster information is irrelevant to the ...
1
vote
1answer
52 views

Change NODATA values to 0 in Qgis

I know this question has been asked already in this forum, but I couldn't find an easy (for me, a rookie) solution for my problem. I have an RGB 3 band file which, in some pixels, has i.e. R no data ...
3
votes
1answer
193 views

Split raster into tiles

I have a raster that needs to be split into tiles (each tile a new raster). I have a Shape file with multiple polygons (these polygons are how I want the raster split). I have Gdal and QGIS. Any ...
2
votes
1answer
180 views

3d arcgis raster .tiff image to CFD software

I am trying to export 3d raster image prepared in ArcGIS to cfd package such as Fluent. I was wondering if anyone has experience to convert raster image to autocad 3d format, stl, vrml or any other ...
1
vote
1answer
31 views

Area estimation using raster image

I have a map of trace gas (NO2) distribution over big cities and other anthropogenic objects. The purpose is to estimate the area of distribution. I attached the sample image to illustrate what I do. ...
2
votes
2answers
182 views

Group adjacent polygons with similar (but not same) attributes

In ArcMap 10, I have a few dozen tiffs with cells that represent habitat area that has been burned. Each burned cell has a Julian date of the fire associated with it. I want to end up with polygons ...
1
vote
0answers
19 views

how to generate a raster with its spatial reference from an array(or matrix) by using pyqgis

I used arcgis to generate rasters from txt files by a certain python api,but i am not familiar with qgis,and now i need generate some rasters from txt files by using pyqgis.The resulting rasters ...
0
votes
1answer
18 views

My raster does not line up with rest of vector shapefiles, even though both rely on NAD 83

I started creating a map in ArcMap by adding vector shapefiles. All of my vectors have data sources as: Data Type: Shapefile Feature Class Geometry Type: Line Projected Coordinate System: ...
2
votes
0answers
35 views

R Efficient Way to Resample, Crop, and Mask a Raster Image

Does anyone know an efficient way to resample an image? I am currently trying to crop a large image and clip 2 regions from a shape file. From this clipped image, I would like to increase the pixel ...
1
vote
0answers
31 views

Get distances between boundaries from an SpatialPolygon and raster pixels

I am trying to calculate the distance from several pixels of a raster to a boundary of some polygons in R as it is showed in the image. I have two problems: How to correctly define a boundary from ...
2
votes
0answers
13 views

Export RAT (KEA driver) to Shapefile

I have a dataset of rasters (driver kea) whose has, let's say, 20-30 attributes in their RAT. I'm realizing how to have these attributes in shapefiles (without using proprietary software). I've read a ...
3
votes
1answer
39 views

Raster Layer Statistics CSV Output using QGIS Graphic Modeller

I am currently working on a project where I am using historical cloud coverage from MODIS Cloud Fraction data to try and estimate future cloud coverage of any particular month. I currently have ...
0
votes
1answer
39 views

Reprojecting and retiling a large set of tiles

I am trying to understand the process to re-project and re-tile a set of raster (GeoTiff) but can't wrap my head around how to use the different GDAL tools to achieve my goal. More concretely, I ...
1
vote
1answer
303 views

How to use GDAL to burn a selected value from one raster into another?

I think this should be a relatively simple process, but I'm not quite sure how to approach it. I have a shapefile containing 1000's of polygons. I also have 19 rasters. All of the polygons fall ...
12
votes
9answers
26k views

Get boundary of raster image as polygon in ArcGIS Desktop?

I have a rectangular raster image in ArcGIS. My question is: how can I produce a polygon which is just the extent of the raster image? That is, I want to have a polygon layer with a single ...
1
vote
2answers
38 views

R calculate raster cell size in map units

I have a RasterLayer and would like to know the cell size. I haven't find any function in the packages :-S . Does someone have an idea ? info about the RasterLayer class : RasterLayer ...
8
votes
2answers
735 views

Histogram Matching using Python to improve mosaicking process of multiple overlapping rasters?

I am trying to do histogram matching using Python to improve the mosaicking process of multiple overlapping rasters. I am basing my code on that found at: ...
1
vote
1answer
24 views

inserting value from raster into overlaying point field

I am using ArcGIS 10.3 for Desktop. I am using an etopo bathymetry map and would like to determine the depth of ~50k points in another layer. I am sure there is a simple tool for this but I am ...
0
votes
1answer
27 views

Defining the correct AEA proj4string for FEWSnet Rainfall Data (Southern Africa) in R [closed]

I have some general questions about how to go about solving this problem: I am trying to incorporate FEWSnet's monthly Rainfall Estimate data from 2014-2015 for Southern Africa into an analysis where ...
1
vote
2answers
44 views

R: aggregate raster with 'mode' function - how does it work?

I want to aggregate a very fine resolution raster at various coarser resolutions (that represents many 1000s of categorical polygons). The aggregate{raster} function is what i've traditionally used, ...
1
vote
0answers
17 views

Access MEM data from GDAL?

I don't have any answers (yet) from from previous question on GDAL memory raster + OpenLayers, so i'll try to ask an easier question :) Anyone knows how to access GDAL memory with command lines when ...
1
vote
1answer
407 views

Selecting raster data by location: for raster and feature class data

I have rasters covering certain spots in my environment, I'm looking for a way to extract the values which occur at locations which are defined by a selection of feature layers. I've tried with the ...
1
vote
0answers
28 views

How to generalize a raster with noisy edges with ArcGIS Desktop?

I'm trying to generalize a raster to get clean edges (see sample and "optimal" result below). However the borders bleed into each other to a rather high degree. I hacked away at the raster using ...
4
votes
2answers
48 views

Least Cost Path Distance to nearest polygon

I have multiple polygons (destinations) and an elevation raster. For each raster cell in my study area, I need to calculate the distance to the nearest destination polygon. If I use the 'as crow ...
0
votes
0answers
17 views

Raster colormap setting in Arcmap not honored in GP tool

I am working with digital versions of paper maps. Here is what I am attempting to do: In Arcmap determine the value in a raster's colormap that is the undesired black mask / "no data" section. Set ...
2
votes
2answers
254 views

QGIS raster clip error: Cutline not of polygon type

I have a raster file and want to clip it, but I'm getting this error: "ERROR: Cutline not of polygon type" what does this error mean and how can I resolve it?
0
votes
1answer
260 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 ...
1
vote
2answers
64 views

Improves performance on R working with raster files

I´m trying this code to look for NA and negative pixel values and replace it for 0. But it´s too slow. Any tip for improve the performance of it? "all.files" is a list of address of the images. "r1" ...
2
votes
1answer
40 views

Automated clearing /tmp using QGIS batch processing?

I'm currently batch processing a bunch (~200 x 200MB) of ascii grid surfaces using some SAGA and GDAL algorithms in QGIS and have been running into "out of storage" errors. The issue is that between ...
3
votes
2answers
36 views

What is the SRID of LCC projection?

I have a raster file with LCC projection and a point dataset with SRID 4326. I want to extract raster value to point. When I use the query SELECT ST_Value(rast, geom) val FROM testraster5, ...
1
vote
1answer
28 views

Why doesn't Ordnance Survey street view raster layer appear on qgis map?

I've downloaded the relevant 100 km square of OS Street View raster data and have added the relevant 5 km square to a QGIS 2.8.2 map of scale 1:1500. The layer can be seen in the layers menu but not ...
0
votes
0answers
6 views

mapnik.Gdal(file=my_latlon_raster_file_path) returns a datasource with an empty all_features() list

When I get my mapnik layer datasource like that for a raster file: layer = mapnik.Layer(my_raster_layer_name) layer.srs = my_srs layer.datasource = mapnik.Gdal(file=full_path_to_my_raster_file) and ...
2
votes
0answers
33 views

Extracting Mean from Raster and Writing to Table in ArcPy?

I am simply trying to extract the mean of each raster within a geodatabase and write the value to a table. I have done this successfully with another set of rasters, but now I keep getting the ...
4
votes
1answer
235 views

Calculating parameters for SQLServer raster to Esri grid script?

My question is related to How to convert SQL Server Rasters to ASCII Grid? I would like to transform the data in the database into Esri grid format. I would like to write the program/script myself ...
0
votes
1answer
24 views

Masking low quality raster with polygons in R gives weird overhang?

I am pretty new to R, and have been attempting to use the mask function on a raster image of 250mx250m resolution. My problem is that for some reason I am getting overhang, as there are pixels which ...
1
vote
0answers
23 views

Polygon to Raster tool while keeping less than maximum values

I'm trying to convert a very large, detailed polygon to a raster with a coarser resolution in ArcGIS 10.1 using the polygon to raster tool. The value field is a percentage and the cellsize must be the ...
1
vote
0answers
18 views

Choosing pixel size when projecting raster from geographic to projected coordinate system

I have a raster showing animal abundance in all of Canada. The raster was created unprojected in GRS 80 with a pixel size of 0.0833 decimal degrees. I was ask to project this raster to Canada Albers ...
1
vote
1answer
39 views

Performing raster calculations with more than two bands in PostGIS?

We need to perform raster calculations using more than two bands in PostGIS. At the moment, ST_MapAlgebra has a two-band form but doesn't support more than that. I'm open to any solution others ...