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

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230 views

QGIS - Android, loading a .tif file

I have a .tif file I would like to use as my base map on the Android version of QGIS. However, when I try and load it as a raster layer, it states that this is not a correct raster source. Is there a ...
0
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2answers
114 views

GDAL clips raster at wrong position

I try to clip raster data with GDAL (in fact I am using QGis, which produces me a command line for GDAL) The raster has been transfored to EPSG:3857, which is also the projection of the shape file ...
6
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0answers
667 views

What is the correct syntax for using gdal_rasterize with a PostGIS datasource [closed]

I have a multipolygon layer in PostGIS and I would like to use gdal_rasterize to generate a raster. I cannot find the correct syntax to specify PostGIS as the data source. $ gdal_rasterize -a ...
2
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1answer
255 views

How to smooth a raster in a rectangular fashion using gaussian blur?

How do I adjust the code for the Gaussian Blur posted in the thread: What raster smoothing/generalization tools are available? to retain the resolution/gradients in the y direction and blur only ...
0
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0answers
393 views

Use a WMS raster in ArcGIS 10 and combine it with vector layer

I have connected to a WMS server which provides raster images, more specifically, LIDAR surface elevation maps. I also have a vector layer which contains the outline of buildings. I would like to ...
0
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0answers
958 views

Manually edit cell value in DEM in Arcmap10?

Is there any chance that I could manually pick a group of cell in DEM, then edit the value of them in Arcmap 10? I know about the Aris Grid Editor for Arcmap but it requires licence and it's too ...
2
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1answer
1k views

Why does copy convert my Tiff raster value range?

Recently I have worked with some raster dataset. And I found there are different kind of raster dataset. Till now I have worked with grid type raster dataset and my add-in works fine with this type. ...
3
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1answer
740 views

gdal_merge.py with single band raster

I'm trying to mosaic the True Marble world imagery 250M geotiffs using gdal_merge.py though one of them doesn't have RGB bands like the rest and gdal_merge fails (same number of bands is listed as a ...
3
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1answer
2k views

ArcGIS - Export raster keep color scheme

I have a *.flt raster loaded in ArcMap. I would like to export this raster as a georeferenced tiff file keeping the color scheme I have provided in the symbology. I right click in TOC, Export Data ...
2
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2answers
1k views

Stripping spatial reference

I am creating an exercise for remote sensing students and would like to take an existing raster and remove the spatial reference from the file so that the students can practice using another image to ...
3
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1answer
440 views

how to rename the band-names of a layer stack?

I created a layer stack of 20 images (all GTiff-files) using the gdal_merge tool in QGIS, available at: raster > miscellaneous > merge The result is a GTiff layer stack of the 20 images, but ...
1
vote
1answer
297 views

How to replace data in parts of raster A with the equivalent data in raster B? [duplicate]

I have the following problem: I am currently working with Landsat 5 imagery from the tropics including quiet high cloud cover. I have classified raster images with the different land use categories I ...
3
votes
1answer
983 views

Problem about converting raster to polyline and calculating total length

I have raster file of line segment. I need to convert it to line and get the distance of that line. How can i do using Python and ArcGIS 10? I have tried with GIS tools Convert Raster to Polyline but ...
0
votes
1answer
137 views

What's regular blocking arrangement ? (GDAL)

I am using GDAL tools to retrieve PostGiS raster. The code(command line) I am using is as follows : gdal_translate -of AAIGrid "PG:host=localhost dbname='database' user='postgres' password='admin' ...
0
votes
1answer
90 views

Raster Clipping and Manipulation

I have two raster tiff files one is a raster that I created from 2 Foot contour lines, the other raster file is a small area that was surveyed to half a foot accuracy. My question: Is there away to ...
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5answers
644 views

Create world file from kml

I have a KML file for a NASA image. I want to create a world file from it so I can use the image in say QGIS. Is it possible to extract the key info (bounding coordinates) from the KML? It seems to be ...
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2answers
3k views

What to do when raster cell size is larger than zonal vector feature in order to collect statistics?

I am trying to extract the mean cell values for a raster dataset based on a survey grid polygon feature using ArcINFO 10.1. The cell size of the raster dataset is about 4 times the size of the survey ...
3
votes
2answers
5k views

How to convert .geotiff --> .tiff?

How to convert .geotiff files to .tiff files (ordinary plain images)? Basically, I have cropped the image to a rectangle of interest and knowing its left-lower location and having chosen the pixel ...
4
votes
1answer
671 views

mosaic raster to file geodatabase yields missing raster sections

Since upgrading to ArcGIS 10.1 (SP 1) from 10.0, I've been encountering an issue when running the arcpy.MosaicToNewRaster_management() tool with output to a file geodatabase. I'm principally working ...
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4answers
9k views

Get pixel value from a raster in a xy table

I'm trying to find a way to convert a raster (in my case it's a Landsat satellite image) into a table with 3 columns which would represent: 1) x coordinates (the so called "xllcorners" in ASCII terms);...
0
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0answers
21 views

How to convert Rotated Polar grid raster to Non Rotated Polar Raster? [duplicate]

I have a RCM data which is in rotated Polar system , I want it to convert into non-rotated polar RCM. How can i do this things ? Please give some guidance
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1answer
1k views

ArcMap 10.1 - Tabulate Area tool “doubling up” for Overlapping Buffer Zones

This question is related to a previous question I asked: Raster Version of Spatial Join (one to many) I used the Tabulate Area tool to crosstabulate values between an overlapping "buffrast" raster (...
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2answers
15k views

Clipping a raster in R

I am building a map for the northeastern U.S.A. The map background needs to be either an altitude map or a mean annual temperature map. I have two rasters from Worldclim.org which give me these ...
0
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1answer
504 views

value field name after raster to polygon conversion

When I perform Raster to polygon conversion using tool, sometimes it creates a field named "GRIDCODE", sometimes the field name is "grid_code". Why does it create random name of a field?
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1answer
361 views

Raster to polygon conversion's raster field takes only “Value”

Recently I am working with raster data and arcobjects.net. Here I find something new for me. And here some question arises in my mind. I tried to search some document that can satisfy my mind, but I ...
0
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1answer
1k views

Field added to raster data is not visible in attribute table

I am new to raster data and my background is software engineering so this might be a trivial question for GIS specialists. Some raster files have attribute table but some do not. On those with ...
3
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3answers
192 views

Can a single raster pixel hold more than one value?

Can a single pixel of a raster hold more than one value?
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0answers
3k views

Loading raster from PostGIS DB into QGIS: succeeded yesterday, fails now [closed]

I have a PostgreSQL(v.9.2)/Postgis(v.2.0.3) database which includes raster layers (added through raster2pgsql). To open them in QGIS (v.1.8.0-Lisboa), the "Add Postgis layer" menu will not work; ...
4
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3answers
5k views

How can I reclassify a raster to floating point values?

I have a raster of landuse values that I need to reclassify into pollution concentration values. I have the pollution values in a separate table. They are decimal values (ex. 0.0056), and my landuse ...
6
votes
2answers
1k views

How to generate TFW files for a list of images?

I have a few digital images that are not georeferenced. E.g.: Img01.tif Img02.tif ... Img99.tif On the other hand, I have a text file, which contains georeferencing information for these ...
0
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0answers
35 views

Assign value to raster cells within masked area [duplicate]

The answer I previously received for this question did not solve my problem...please keep in mind that I am a GIS beginner, and it's quite likely that I carried out the proposed solution (using ...
2
votes
1answer
569 views

How to read XY, get raster value and then update field?

I've written a script to run through a point layer, using the SearchCursor in the data access module and then read the XY values. Within the with statement, I then use GetCellValue to get the ...
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1answer
253 views

Problem with calculating the total cell values

aa= arcpy.RasterToNumPyArray("water_depth") sum = numpy.sum(aa) print sum -2933737 Why I am getting negative values ? In my raster there is no any negative depth.
3
votes
2answers
425 views

Tabulate Area crashes Python and ArcGIS

I have a script that runs Tabulate Area on a single feature class multiple times with different rasters. In total Tabulate Area runs 5 times. 2 of the input rasters are provided as arguments to the ...
3
votes
1answer
3k 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
0answers
288 views

Different results from Spatial Analyst GP Tool and Python

I am writing a script that has to subtract one raster from another. The rasters I have represent 1) Parking Lots (1 = Parking Lot, 0 = not Parking Lot) and 2) a buffer around the Parking Lot (1 = ...
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0answers
606 views

QGis Grid statistics for polygons error - Module caused access violation!

I'm trying to calculate statistics for a raster layer using an overlaying polygon layer, I'm using SAGA "Grid Statistics for polygons" function, but it returns an error, sadly.. So in the sextante log ...
4
votes
1answer
425 views

Raster to vector with gaps in Landsat ETM

I need to find size of water area from a raster (jpg) using QGIS 1.8.0-Lisboa. The raster is a Landsat image with gaps of data in it. I used Polygonize, but the output file shows wrong polygon size ...
1
vote
2answers
763 views

Add a time dimension in ESRI mosaic raster dataset

I am in the process of creating a script to pull daily .asc files from a ftp server, convert them to a raster format, and push them into a mosaic raster dataset. Ultimately, the raster dataset will be ...
1
vote
1answer
630 views

Extraction of raster cell values based on 'rgeos' and 'raster' buffering approaches in R

I am trying to extract cell values from a raster that lie within a certain distance from a given location (i.e. buffering). Evaluating different approaches, I found out that applying gBuffer(..., ...
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0answers
38 views

How to combine two rasters, preferring the values of one over the other? [duplicate]

I have two rasters that I need to combine (not using the Combine tool). The values of the 1st raster are preferred to those of the 2nd raster, so I want to keep these values if they exist. Where the ...
1
vote
1answer
260 views

Calculating Volume of Reservoir using python and ArcMap10? [duplicate]

I have a raster file with different water depth in each cell. I am using Aster DEM so my resolution of that file is 30m by 30m. Now I want to calculate the total volume in that area by multiplying ...
3
votes
1answer
1k views

Why is Orthorectify button not active in Image Analysis Windows in ArcGIS10?

I wanted to Ortho rectify GeoEye HR imagery using existing RPC and IFSAR DTM in Image Analysis. According to ArcGIS Resource center http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/...
3
votes
3answers
2k views

Batch clipping rasters in QGIS?

I have been able to batch clip rasters in one directory using python in ArcGIS. However, I am not sure how to do the same in QGIS using the Python console. Is this possible?
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0answers
30 views

Raster attribute field error [duplicate]

I am trying to add jpegs to a raster data type attribute field. I want to this field to be managed by the file geodatabase. When I load the photos and try to save my edits it get various errors but ...
9
votes
2answers
1k views

Creating randomly shaped clumps of cells in a raster from seeds of 1 cell/pixel?

As my title says, I wish to "grow" clumps of cells from seeds within a raster. My base raster is full of 1's and 0's, 1's indicate land and 0's sea/NA areas. From the 1's I wish to select 60 random ...
9
votes
2answers
8k views

How to extract values from rasters at location of points in R?

My question is about extracting values from rasters at the location of points. With the function extract this is very easy, and the function gives me a dataframe with the values of all the variables ...
2
votes
1answer
949 views

Web mapping application with time slider and raster data

I need to create a web mapping application that can show raster layer of historical maps with a time slider. Basically, something like this: http://goo.gl/GYHOX I have different maps of different ...
2
votes
2answers
1k views

Create Raster file in R from Matrix and latlons

I could use some advice on how to create a Raster file in R with a Matrix of data points and the coordinates stored in a separate file. Both, data and coordinates come from a NetCDF file. I extracted ...
0
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1answer
714 views

how to create a new raster from one field of a raster with several fields in a RAT

I have a raster with an attribute table containing many fields. I want to create a new raster from one field using ArcGIS 10.1.