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

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10
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3answers
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How to fully load a raster into a numpy array?

I have been trying to check my filters on DEM raster for pattern recognition and it is always resulting in missing last rows and columns(like..20). I have tried with PIL library, image load. Then with ...
4
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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 ...
5
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1answer
1k views

Export selected raster cells to polygon

I have selected certain values in a raster (roughly 1000 cells), and would like to export them to be able to create a polygon. Converting it to points first then to polygons does not work. Can anyone ...
2
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2answers
1k views

query raster in ArcGIS 10

I am using ArcGIS 10 (includes spatial and geostatistical analyst). I have a raster (GRID) with a value range of -167 to 18. I would like to query the raster and create a new one with only the values ...
3
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0answers
185 views

Geoprocessing Service to return Multidimensional Raster from a NetCDF file

I have tried to make this work for weeks with no results. I am trying to create a model in ArcMap that uses the Multidimension Tool "Make NetCDF Raster Layer" and return a raster to which I can apply ...
1
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2answers
486 views

Cannot get arcpy.MosiacToNewRaster to work with list

Below I have a snippet of a much larger code that I cannot get to work and I am not sure why. It seems that I always have trouble using arcpy functions with rasters. Can anyone help me get this code ...
1
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4answers
577 views

Determining gradient of road segment

I've a shapefile of roads data. It contains information about terrain of road segments, i.e., hilly, flat, undulating, etc. I want to determine gradient of every road segment. I know this might ...
0
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2answers
449 views

Set Raster Cells Based on NoData from other Raster

I have just no clue on this problem. I want one raster to set its values to 0 or NoData based upon another raster noData or 0 values. It's like a reclassify, but between two different raster's. I have ...
4
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3answers
1k views

How to speed up Postgis raster layer display in QGIS?

i've been importing some digital orthophoto geotif files into postgis 2.0.1 via raster2pgsql tool (i also made 3 levels of an overview table - pyramid). Then i tried to import the layer into qgis via ...
2
votes
2answers
200 views

Is there anywhere that I can obtain global UV data in either raster or vector format?

I'm looking for some UV data (currently with no spatial or temporal resolutions in mind, but ideally split into UV-A and UV-B) for the whole earth. Can anyone recommend a source for data like this or ...
0
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0answers
223 views

QGIS Invalid Data Source in raster calculator

I just installed QGIS and am new to it. I want to use the raster calculator, but after assigning a name to the output layer QGIS tells me "Invalid Data Source" and "filename.tif is not a valid or ...
9
votes
6answers
7k views

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): ...
2
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0answers
357 views

Can hdf4 images be used in QGIS?

I'm trying to use hdf4 raster image in QGis 1.8. This image come from the MODIS satellite. I've loaded the file, it appears on the layer window bu it is impossible to see it on the display window. ...
6
votes
3answers
3k views

How can I select vector features that overlay raster in arcpy?

I have two datasets: point feature class and raster (stored in file geodatabase). The spatial extent of the raster is smaller than the point dataset. Is there a way I could select (or create new, ...
10
votes
2answers
457 views

What are the advantages/disadvantages of populating a PostGIS database with Raster information?

...as opposed to keeping the rasters as locally stored GEOTIFFs? I have a large project that will require making available approximetely 50,000, 10mb GEOTIFFs as WMS to an OpenLayers based web map. ...
1
vote
0answers
198 views

Reclassify ESRI raster using variables from a SQL Server table (connecting with pyodbc)

I am trying to reclass a raster file (representing vegetation and land cover types) using values stored in a SQL Server Express table. I have a set of ~400 species records in the table, with each row ...
5
votes
1answer
2k views

How do you add a long list of rasters together in Python?

If you have produced a long list of rasters (lets say 50) and want to add them together, is there any shorter way to write in python rather than typing all the inputs, like so: outRas = inRas1 + ...
0
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0answers
185 views

SAGA grid VRT, file how to apply a LUT?

I've created a heap of saga grid files for some hydro survey work. I'm looking at a way to read these into a mapguide raster/grid layer, I'm able to load up the grids using a vrt file, I can't figure ...
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1answer
481 views

how to make grid cells by point data [closed]

I have a csv data. the X, and Y columns show bottom left corner of each grid. It is supposed to show as grid square, but it shows points. what is the problem? and is there any way I can make cell ...
5
votes
1answer
852 views

Are there limitations using a PostGIS out-db raster?

I have been trying to import a large raster into a PostGIS 2.0 database and hit a few stumbling blocks. Initially when I tried to import the raster using raster2pgsql, I would receive the following ...
0
votes
1answer
182 views

QGis : superimpose 2 rasters georeferenced (adjustment)

I am pretty new in QGis and I encounter the following problem. I have 2 rasters, let's say, "cadaster" and "tranchot". The raster "tranchot" was georeferenced from the raster "cadaster" with QGis. ...
2
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2answers
896 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 ...
3
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0answers
125 views

How to view Esri GRID format file in wxpython file browse window? [closed]

I'm trying to browse for all kinds of vector and raster data using a filebrowsebutton. The problem is I don't know how to let the browse window see the Esri GRID files (which contains a folder and a ...
8
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1answer
3k views

GDAL RasterizeLayer Doesn't Burn All Polygons to Raster

I am trying to burn a shapefile to a raster using GDAL's RasterizeLayer. I pre-create an area of interest raster from a different shapefile, given a specific pixel size. This AOI then serves as a base ...
2
votes
1answer
2k views

Creating a raster map using Excel file and calculating averages

I am working on my Master's thesis and have thought about using ArcGIS to create a raster map of latitude/longitude (0 to 360 degrees) temperature data (in Excel format). This temperature data ...
2
votes
2answers
2k views

How do I use ranges for raster colour map in QGIS

I have a raster layer in GeoTIFF format, with continuous data values between -1 and +1. For the colour map, I would like... >0 to be green = 0 to be grey <0 to -0.25 to be pink <-0.25 to ...
2
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0answers
160 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 any one has experience to convert raster image to autocad 3d format, stl, vrml or any other ...
4
votes
1answer
320 views

Stripes in Landsat-image after topographic correction (SAGA)

I got stripes in my topographic corrected Landsat images (see second image below). I used SAGA GIS 2.0.8 at xubuntu 12.04 Image and DEM are in the same projection, tried it with EPSG:32636 and ...
1
vote
0answers
125 views

Corrupted rasters after import into ArcGIS FGDB

I have been seeing a number of corrupted rasters recently after importing them into file geodatabases (FGDB). The image below left shows a .tif prior to the import, while the image to the right shows ...
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0answers
630 views

How to add ECW support to GDAL bundled with PostGIS Windows

I'm currently trying the new raster functionalities of PostGIS 2.0 and I successfully imported some GeoTIFF file into PostGIS (although it only find one band so it's all black and white for some ...
2
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0answers
593 views

Output raster extents when using the Spatial Analyst Extract By Mask tool to clip a raster

I am using ArcGIS 9.2 and I have a simple python script that does the following : Loop over a polygon feature class (shown in red in the image below) For each record, create a feature layer to ...
5
votes
2answers
1k views

Rasterize a vector layer in PostGIS

Related to this question asked here on gis.se and this thread on postgis-user, has anyone worked out a good solution for in-database rasterization of a vector layer using PostGIS? It sounds like the ...
6
votes
3answers
3k views

How to smooth / “reinterpolate” a raster with GDAL?

Short: I want to change the resolution of a raster and smooth the gray ramp like shown in the images bellow. The preference is to use GDAL, PIL or Numpy. Description: I'm kriging points into rasters ...
5
votes
4answers
5k views

Advanced colour palette for raster data

I'm working with satellite date namely chlorophyll and sst. Each geophysical parameter generally has standard colours to represent them. I'm importing geotiffs into Qgis and I'm having difficulty ...
2
votes
1answer
480 views

polygonize and raster tools [closed]

ok simplest question i have asked i think. but im a running QGIS 1.7.4 and there are no other tools in the dropdown menu other than raster calculator. I have seen in a lot of online demos tools below ...
4
votes
3answers
485 views

How to store raster data outside postgis database

I am able to import raster data easily into the database and view it through QGIS. However, I am unable to view the raster layer in Arcgis. Now I want to know how to create a table with a reference to ...
2
votes
1answer
579 views

Accessing PostGIS raster data using Query Layer in ArcGIS Desktop?

I tried to load raster file (jpg) into post gis using the syntax provided here "C:\Program Files (x86)\PostgreSQL\9.1\bin>raster2pgsql -I -C -e -Y -F -s 102003 -t 300x300 ras_test.tif ras_test1 | psql ...
5
votes
1answer
864 views

Identify Polygons on raster image

I have OS street view mapping as raster images. Is it possible (without the obvious of tracing each dwelling) to identify all polygons on each tile. To clarify, My ultimate aim is to produce a ...
3
votes
1answer
874 views

Merging raster data with different resolutions

I need to merge different raster datasets which have one layer and contain discrete values to a layer stack. The resolutions of the data can have any value so not only multiples of the resolutions ...
5
votes
1answer
1k views

Why do TIF loaded into PostGIS lose their colormap?

I have successfully loaded a TIF image (using raster2pgsql) into my PostGIS 2.0.1 database. I can load the raster image into QGIS and it displays in the correct space. However, it has lost all colour ...
0
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1answer
623 views

“Display Background value ”0“ raster”

While publish raster layer in geoserver it shows background as black. How to remove the black color. if there is any options to permanently remove the black color.
3
votes
3answers
455 views

Unattractive image artefact when exporting from QGIS's Print Composer

When I export my map from Print Composer in QGIS 1.7.4, an odd red band appears across the middle of the image. This happens when I export to both PNG and PDF. Its not visible on the screen before ...
1
vote
1answer
2k views

How do I add TIFF files to one layer/raster catalog?

We have several TIFF images (already tagged with position information) we want to load as a single layer into the map. It's the first time I dig into this raster/topology thing, but at least I managed ...
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2answers
660 views

how to remove the color formed on the edge of satellite image?

my AOI requires two scene of satellite image but when I try to mosaic the images using ERDAS imagine, the color of the edge is seen forming black line after mosaic! so please how can I remove the ...
5
votes
3answers
2k views

NoData values recognised in raster in ArcGIS but not following symbology rules

I have a GeoTIFF raster in ArcGIS, which can be downloaded from the following two links: http://www.rtwilson.com/downloads/MODIS_MOD04_16-06-2006_Subset.tfw ...
2
votes
1answer
525 views

Building a virtual raster catalog

I am very new to using GIS software so apologies if this is a silly question. I am trying to build a virtual raster catalog to allow me to work with OS address base and codepoint data sets. ...
3
votes
1answer
4k views

Converting Raster Data to Polygon data

I am trying to convert a raster data to polygon data. Previously I was using the shapefile.py to create point data on individual lat/lon on the raster. But that will create a Huge data and querying it ...
6
votes
3answers
3k views

Raster: How to get elevation at lat/long using python?

I was wondering if anyone has some experience in getting elevation data from a raster without using ArcGIS, but rather get the information as a python list or dict? I get my XY data as a list of ...
7
votes
2answers
999 views

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 ...
10
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3answers
3k views

How can I mosaic images in ArcMap without it affecting the colour?

This is 4 images (NE, SE, NW, SW) sections of imagery. They have some overlap between them. Working with 1m 3-band orthoimagery. Different parts are sometime flown at different times/sources hence ...