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

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20 views

QGIS Export section from raster to AutoCAD

QGIS Windows 7 I have a raster which displays the flood depth over my site. What i would like to do export to AutoCAD an outline (maybe as a polygon or line) of the sections of the raster which are ...
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45 views

Clip .hdf (MODIS) rasters by shapefile

I am trying to do a temporal analysis on vegetation quality so I downloaded a MODIS .hds raster from earthexplorer. When I opened the file into ArcMap 10.2.2, it came as a group of 11 rasters. I stuck ...
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61 views

how to use raster layer (map image) as base layer in geoserver+openlayers and vector layers on top of that?

I am using Openlayers + Geoserver for rendering data on India Map. I am able to do it. However, the India map generated from Opensource shape files doesnt look good. So, I want to use Better India ...
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29 views

Updating/replacing GeoTiff data store on file system causes GeoServer to halt

I have a few hundred raster layers that are updated at least 4 times a day. The GeoTiff's are updated directly on disc. I'm running it as a windows service and I can sell the wrapper app logging the ...
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55 views

How to speed up raster/map algebra in PostGIS?

I am testing map algebra with PostGIS (2.1 with PostgreSQL 9.3) on two images, and found it to be rather slow. For example, dividing two images of 7200 * 3600 pixels took 110 ~ 120s on a desktop with ...
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32 views

A Distributed Cost-Distance Algorithm

I'm currently trying to implement a distributed cost-distance algorithm, however I can't seem to invent my own and still make it fast. I've been googling around a bit but haven't found anything that ...
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20 views

Raster import problem

I have raster images (orthos) and feature layers in a GIS program (Global Mapper). When I import these files with the same CRS into QGIS they are literally 9000 miles apart and I cannot figure out ...
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17 views

How to summarize canopy cover at a minimum mapping unit using ArcGIS

I am working with Landfire data and I have a project which requires that there be no area under 10% canopy cover at a 5 acre scale. I am going to use the Landfire CC2010 data and use a 5 acre moving ...
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80 views

Scatter plot of two rasters in arcmap for intersecting cells

How do I make a scatterplot of two rasters in arcmap which will plot the two rasters' cell values of the same cell against each other (for every cell where they intersect). I need to first create a ...
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25 views

Has anyone success using subset an image such as NAIP?

Has anyone any luck subsetting a small part out from NAIP? I'd like to hear your feedback on pros or cons on how to subset an image from NAIP despite they are in mrsid and their uncompressed file size ...
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102 views

QGIS raster symbology problem in 2.6

With the new 2.6 QGIS version I often have problems with raster colors. For some reason certain pixels do not display initially, but if I move the raster a little spatially they show up.
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32 views

Adding Raster Layer in C++ application always result in layer invalid

I am trying to add a raster layer in c++ application with QtCreator and QGIS 2.6.0. My code is as follows: QgsRasterLayer * layer = new ...
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79 views

Reclassify raster value

I'm curious if anyone has been able to change one individual value in a raster file? I'm using Arc 10.2 and trying to change the value 99 to -2 for 144 files using model builder. So far, I've only ...
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21 views

Change “World Size” with gdal2tiles.py

When I use the flag "-p 'geodetic'", the output is a world that is 512x256px at zoom level 0. In order for it to overlay with other datasets, I need it to be 640x320px at zoom level 0. I am looking ...
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22 views

Script Efficiency

I have been working on a script to read pixel values and print the values out to a text file. This is currently working but takes around two hours with a 6.6gb file. This is to replace an older script ...
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45 views

Apply raster contraints on single table with multiple files

I have a raster table (pre-created using CREATE TABLE) containing multiple individual raster files that I append piece by piece to a final table. The table itself is in its own tablespace 'gisdir' and ...
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16 views

How to implement gs:storeCoverage with GeoServer scripting

I was wondering if it is possible and how to implement the service gs:storeCoverage using the scripting facility (e.g. with python or groovy). The reason I ask is that gs:storeCoverage is not of ...
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60 views

WPS: how to write output to a raster layer in GeoServer

In GeoServer vector-based Web Processing Service (e.g. gs:Import), we can have the output saved to a GeoServer Layer, as described in the documentation. Outputs Name Description Type ...
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24 views

Update Raster extent

How do you update raster's extent after you export the raster ? I forgot to enable the Date Frame rather than it's original Dataset ? Thanks.
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21 views

PostGIS raster write support in R

I want to push/write some generated raster layers to my postgres database directly in R. In theory this could be supported by the rgdal package, but sadly it isn't. In the latest version only copy, ...
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50 views

Problem with Raster Calculator in Model Builder

I have created a model which repeatedly uses the raster calculator. My problem is that unlike that of the other tools, the output name of the raster calculator does not change. This means that I can ...
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83 views

Find correct SRID

I'm learning PostGIS raster, and importing GeoTiff with raster2pgsql. This command line tool states: -s <srid> Set the raster's SRID. Defaults to 0. If SRID not provided or is 0, ...
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83 views

Setting raster resolution in meters when working in a Geographic Coordinate System

I work in WGS 84 (Geographic Coordinate System) in ArcGIS 10.1. I need to create a raster specifying its cell size in meters, and output it in WGS84. Is it a good solution (towards a less shape/area ...
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30 views

Interpolating points to surface not working

I am trying to create a surface from points using IDW interpolation. Have tried both 3D analyst and Spatial Analyst tool with my selected xyz data sheet. It appears to process and I don't get an error ...
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131 views

How to correctly render a raster Layer to GTiFF with QGIS python console?

I am trying to render a map from a raster layer. As recommended in pyqgis cookbook and here(osgeo.org) I use QgsMapRenderer(). I am able to produce a picture but it has not appropriate extent and ...
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56 views

IMG and geoTIFF raster extraction

everyone. I'm very new to GIS technologies. Somehow, i need to extract raster(RGB data) data from geoTIFF and IMG files. What is the fastest way doing it?
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65 views

Ortho-rectification of Aerial Image

I took an aerial image of our farm using RC quadcopter. How am I going to orthorectify this image? Please can you help me with detailed instructions/methods involving the process.
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118 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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54 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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58 views

analysis of srtm data for gaps

I need to analyse the SRTM DATA (1025 X 1025) of a particular terrain which has gaps or voids. Could anybody suggest a solution to find the percentage of gaps or voids in the SRTM data? I would like ...
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78 views

Create global raster layer with latitude values of each cell in QGIS

I have a raster with a 0.0083 degree resolution (WGS 84) of which I need the area of every single pixel. An easy but compute-intensive approach is explained here but as I need to work with bigger ...
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26 views

Text in POSTGIS Raster

Is it possible to add text/annotation to a raster generated in Postgis raster? Specifically I need to do this within the database if possible and am looking for an option that does not require an ...
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87 views

Polygonize only pixel values of 1 from a raster

I have a raster mask that I have created in QGIS (2.2.0) that consist of 0, 1 and nodata values. I would like to end up with a polygon dataset that consist of only the value of one pixels from this ...
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87 views

How to reassign the values of a raster, based on the pixels of the raster beneath it?

In ArcMap 10.2.1, I have two rasters. Raster1 shows the extent of a habitat, and each pixel contains a categorical value for its land cover type (values 1-3). Raster1 has the smaller spatial extent of ...
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70 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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50 views

Euclidean Distance Function performed on unprojected data

I am looking to perform a simple multi-criteria analysis on a data set comprised of two criterion: occurence of wildfires and road accessibility. First, the project CRS was enabled with "on the fly" ...
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101 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. ...
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73 views

Overlaying Line (Vector) Layer on Raster Zones?

I will make my best attempt to clearly explain my problem. I am using ArcGIS 10 I have a raster layer with 3 values that make up zones. For the purpose of this example, lets say these zones are ...
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58 views

How to mask an vector field layer in MapServer?

given this layer def: LAYER NAME "waveswell_sigheight_grid" TYPE POINT CONNECTIONTYPE uvraster STATUS OFF #MASK "water_outline" #I get a "no data received" error in my browser ...
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67 views

Bi-Weekly NDVI data into monthly Datasets

I have NDVI data in both Ascii Grid format (0.250 degrees resolution) and raster format twice a month like: ndvi1981_07a ndvi1981_07b I would like to combine these bi-weekly values (average) into ...
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19 views

Oncoming intersection or intersection density

Through the use of Android and its on board GPS module, I am looking to calculate the density of intersections in a given area. Say 1 km x 1km. How would I go about accomplishing this? I am new to any ...
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36 views

How do you visualize change in rasters over time in CartoDB?

I have a series of satellite image rasters. I need to show the change over time of these rasters. Would the best way be to change the basemap with the click of a button for each? Has anyone got an ...
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52 views

Qgis Server, show Oracle Georaster dynamically

I have an Oracle Spatial database and I use rasters (SDO_GEORASTER). I can render some rasters on a web page with Qgis Server : when I render the maps on the webpage, it come from a qgis project ...
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22 views

gt:VectorToRaster in Openlayers

i would like to opa vector table using "gt:VectorToRaster" a WPS function in Openlayers. my vector table is stored in Postgis 2.1 and published in geoserver. i need the code to do this, can you help ...
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265 views

R plot raster with real colors

I'have a raster image from Scran25 IGN. In Qgis, it opens perfectly but in R (with rgdal or raster packages), I do not know how to keep the original colors like this exemple? I have tried ...
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45 views

rasterize table polygon postgis 2.1

I would like to rasterize a postgis 2.1 polygon table, but I don't undersand how to create the SQL function syntax for ST_AsRaster. My vector table has 3 fields: gid, recharge, and geom. The SQL ...
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80 views

GeoTIFF Mosaic/Crop/Translate: Easiest Method in QGIS?

I routinely have to mosaic multiple GeoTIFFs together, extract a rectangular area, and save that area as a JPG with a world file. Typically I've been using commercial software for that (Geographic ...
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116 views

QGIS-Merge or create virtual raster files without losing definition?

I am new to QGIS and relatively new to GIS (so please be aware I am not that familiar with a lot of technical terminology). I am trying to merge several tiff files as either a virtual raster or a ...
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214 views

How to calculate a population weighted centroid using a raster and shape file in QGIS?

I am very new to QGIS so please help me with a step by step answer. I have a raster file with population count and a shape file based on a large population and shape file. I have successfully created ...
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11 views

View information raster data in postgresql

I download and use raster2pgsql.exe import tiff image into postgresql. Can i use the query to retrieve the information of the image does not? Information such as: date of capture, capture time.