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

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7
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2answers
827 views

Extracting roads out of Landsat raster images

For a study into the expansion of road networks in the rainforest I am trying to extract roads out of Landsat images. We already have sharp and cloud-free composites on which the roads are clearly ...
3
votes
1answer
346 views

Build Raster Attribute Table with GDAL Utilities

Is there a way to build a raster attribute table using one of the GDAL utilities? I know you can view it using gdalinfo and I have successfully created one using Python, but it would be so much ...
2
votes
1answer
114 views

Are there any open source distribution raster merging functions within JTS or GeoTools

I'm looking for something similar to the combine function from the ISelectionSet interface from ArcObject's SDK 10 .NET framework on a more scaled down level. Ergo, I don't plan on using that ...
1
vote
1answer
121 views

Set certain amount of pixels to 1 inside of a polygon (GRASS)

I have a rather coarse vector map with polygons and want to calculate a (sufficiently) finer raster map defined by spatial extension and resolution. Every polygon of the vector map has a value ...
1
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3answers
142 views

Applying rotation before FeatureToRaster_conversion?

I am converting polygon shapefiles to rasters. With arcpy I am using the function FeatureToRaster_conversion. gp.FeatureToRaster_conversion(InFeatures, InField, OutRaster, InCellSize) This function ...
2
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0answers
138 views

Plot the Shortest Paths in a Grid without any clash at a point of time

The efficient algorithm needs to be done and proved for the best solution for the given problem: User inputs: (#) Size of the NxN Grid. (N); (#) No. of Paths: Z; (#) Source and Destination ...
2
votes
1answer
294 views

Saving rasters in a Python for loop fails only on last iteration

I'm a newcomer to Python scripting and I'm having what's seemingly a very simple problem but one that's stumped me enough to send me posting to these forums for the first time. I'm using a for loop ...
4
votes
1answer
2k views

Reassigning raster cell values from another attribute in raster attribute table?

I have a large (size of lower 48 U.S.) 100m resolution raster dataset that has a raster attribute table (RAT). The data were created by someone else. One of the attributes in the RAT has the data ...
2
votes
1answer
341 views

USGS GeoTiff extent via GDAL

I have 2006 land cover GeoTiff from the USGS site (for a county in VA, USA). The projection is Albers Conical Equal Area Units. The download came with an HTML metadata file that tells me the geo ...
1
vote
0answers
114 views

jagged edges in mosaic DEM

I encounter edge issues when trying to mosaic USGS NED DEMs in ArcGIS 10.0.0. After projection and aggregation, I attempt arcpy.MosaicToNewRaster_management(). I've reproduced the same results using ...
5
votes
1answer
204 views

parallelization of raster mosaic

I would like to create a raster mosaic of the national USGS NED 30m DEM (~50 GB). I'd like to leverage parallel processing using python multiprocessing module where possible. I'm using ArcGIS 10.0. My ...
0
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0answers
35 views

I need advice in using QGIS Lisboa 1.8 (vol 2) [duplicate]

Possible Duplicate: I need a advice in using QGIS lisboa 1.8(vol 3) My previous question was not clear, so again my question is: In an urban area with polygon and dots, how could I display ...
11
votes
2answers
496 views

Converting ascii windspeed files to rasters

I have been trying to convert windspeed files to rasters without success. It was discussed in an Arcgis forum which I followed. This involved replacing semi-colons with spaces and adding a header. I ...
5
votes
1answer
151 views

GDAL/OGR Determine if dataset is raster or vector

I am writing a script using the GDAL/OGR Python bindings and it is possible that the user may provide a raster dataset or a vector dataset as input. If the user provides a vector dataset, the script ...
1
vote
3answers
2k views

How to subset raster image using gdal?

I have read pixel values of an raster image using GDAL libraries in visual studio 2010(vc++). Now I have to crop the image (subset) according to the grid given in shape file. I have got a code for ...
3
votes
1answer
330 views

An error in raster calculator in Arcgis

I wrote and ran this formula in raster calculator in ARCGIS. But the following error gets me into trouble. Does anyone have a suggestion to overcome this? Here is the formula I wrote and the error ...
2
votes
1answer
202 views

ArcObject 10.1 Java : Raster Analysis

I have been working with ArcObjects Java for a short time and have not been able to find a solution to the following problems: How to get the Raster object from a IRaster reference? IRaster raster = ...
0
votes
2answers
1k views

Difference between Geostatistical Analyst and Spatial Analyst toolboxes for interpolation?

I did interpolation on point data using "Geostatistical Analyst" tool. It gives me surface layer. Then I exported this layer into raster image (by right click on this layer=>export data into raster) ...
2
votes
1answer
470 views

Question about sizes of input rasters for raster calculation

To calculate any formula (conditional statements/relational operation etc) in the raster calculator in ArcGIS using two different sources of raster images, I'd like to know input rasters must be the ...
3
votes
0answers
269 views

Getting coordinates of pixels

I want to compute an area of certain object on a picture using Monte Carlo method. The picture shows some shape on white background. To do so I figured out that I'd get the coordinates of non-white ...
8
votes
5answers
1k views

Finding minimum bounding extent of given pixel value within raster?

I am wondering if there is a way to find the minimum bounding extent for a raster with a particular value. I clipped a raster from a global image and the extent is set as the global extent with a lot ...
8
votes
2answers
2k views

How to reclassify a very large land cover dataset?

Consider the NLCD2001 Land Cover dataset for Alaska (download link). I need to reclassify this dataset so that only pixels of value 41, 42, and 43 are preserved; all other pixel values should become ...
14
votes
3answers
386 views

Is it possible to use symbols instead of colours to visualise raster cell values?

I have a raster image (GeoTIFF) with integer values. I know how to visualise raster values in QGIS using colormaps or similar, but I would like to assign symbols to each colour value instead - just ...
7
votes
2answers
545 views

How to perform enhancement operations on an satellite imagery in QGIS?

I am a new user of QGIS please suggest how to perform image enhancement operations on an satellite imagery like ratioing, contrast stretching, edge engancement, filtering etc. in QGIS?
1
vote
0answers
192 views

How to rename .met file with model builder which uses an iterator to rename .sid files?

I have a model that iterates through a folder containing .sid raster datasets, amongst other types of rasters (so I'm using a *.sid wildcard). I note, however, that ArcCatalog/Model Builder/Rename ...
4
votes
3answers
2k views

Reproduce raster with the same extent, and the same number of columns and rows

I have two raster A and B. A and B have the same grid size but different extent. How can I make A has the same number of columns and rows, as well as the spatial extent of B?
5
votes
1answer
2k views

How do I average a set of rasters?

How do I average a set of rasters? I have remotely sensed chlorophyll a rasters for several days and I need to get an average of the days represented as one raster layer. I've got QGIS 18.0 with the ...
5
votes
1answer
680 views

How to force RGB in a raster in QGIS?

I have rasters in 1 band 64bits float that represent real data values and for which I can set min and max using the stretch to min and max option in QGIS. I would like to convert these rasters to RGB ...
5
votes
1answer
360 views

Simplifying polygons made from binary rasters

I'm using MaxEnt to produce a species presence / absence raster layer. It works fine but I have to choose a cut off point for what constitutes presence or absence. As a result I end up with a lot of ...
2
votes
0answers
52 views

How to change the order of a raster in order to create mosaic with MosaicPro (Erdas 9.2)?

Is there a way to reorder the input files so I can control which ones are on top of the others?
3
votes
1answer
927 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 ...
2
votes
1answer
507 views

MOD 35 Cloud Mask HDF in ENVI

I am having difficulty getting ERDAS or ENVI to correctly read and display cloud mask attributes from MOD 35 HDF files. They files are displayed as 0-255, whereas I expected some kind of code 0, 1, ...
5
votes
1answer
781 views

How to load raster data with hyperlink path in ArcGIS MXD?

I have a problem/question and hopefully someone of you is able to help me: I have thousands of georeferenced raster files which have corresponding polygons (outer borders of rasters) with a hyperlink ...
5
votes
1answer
172 views

Calc bottomline of valleys

Which way do I calculate bottomlines of valleys or even more preceise: which way do I "find" valleys (for example suggested tectonic faults). Sample below shows a height profile (profile from line) ...
6
votes
1answer
533 views

Calculating “relative slope” per Mora-Vahrson method in ArcGIS

I'm a longtime lurker who finally decided to register on the forum (in no way driven by my need to have a certain question answered, of course...). I was contacted by a colleague asking for help ...
6
votes
1answer
247 views

Raster aggregation in ArcGIS Desktop?

I'd like to aggregate a raster from 1m to 6m in ArcGIS with a custom rule. For example, each cell value of aggregated raster = mean value of 5 highest cell values from 36 aggregated values. How do ...
2
votes
0answers
207 views

how to align vector and raster images? [closed]

How to align vector and raster images? For example vector images will be static/rigid and raster image will be morphable. For example I manually do initial guess and algorithm must converge to optimal ...
5
votes
1answer
765 views

Python equivalent of gdalbuildvrt

Is there a way to perform the same task as the gdalbuildvrt utility using GDAL Python bindings? So far I have not found any way to do this other than creating a vrt of a single dataset and manually ...
2
votes
1answer
111 views

d.rast.edit error when attempting to edit a raster

I always get an error when I try to edit cell values in a raster with the GrassGIS command „d.rast.edit“. The error under Windows XP/GrassGIS 6.4.3 says: Exception in thread Thread-29: Traceback ...
2
votes
1answer
209 views

Tiling Rasters based on an existing Polygon Shapefile (Vector Grid)

I have a tile index representing the tile scheme used to tile Lidar data. I want to tile imagery rasters using the same tiling scheme. I have not found anyway using open source tools to tile a ...
2
votes
0answers
75 views

What are the characteristics of a raster to Netcdf layer in ArcMap?

Specifically, when trying to edit the attribute table? This is would be for work purely in ArcMap, and converting raster to Netcdf. I have a land cover layer (that I've converted to a raster to ...
1
vote
2answers
454 views

SAGA-GIS Produces different results in command line than GUI

I have been working on a lidar processing workflow using SAGA-GIS. I determined my workflow on a single tile in the SAGA GUI and now I need to batch the operations on 100 more tiles. I wrote a batch ...
4
votes
1answer
233 views

How to create cohesive Spatial Pixels from Spatial Points Dataset

I have a Spatial Point DF spo (covering an irregular shaped area of interest). The data are not on a regular grid due to crs transformation. My goal is a raster with predefined resolution and extent ...
2
votes
1answer
528 views

How do I pass each parsed file name to the next tool in Model Builder? [duplicate]

I cannot get the Parse Path tool to pass each file name to the next tool. In the example shown, the Raster to Ascii tool will take the first entry in the 'filename' variable list as part of the output ...
10
votes
2answers
983 views

How can I improve my Georeferencing results?

Background This is my second question related to georeferencing naked raster maps in order to re-visualize them on different coordinate systems and in conjunction with other data layers. The previous ...
9
votes
4answers
1k views

How to “clean” and vectorize a raster map?

I'd like to make use of a geological map as shown in the example below, which is only a pretty small and downsized part of the map, so editing/redrawing doesn't seem to make sense in the end. My idea ...
1
vote
0answers
349 views

Raster Over Layer in Leaflet from GeoServer

I want to add a raster over layer onto the base layer and the raster layer is published by a Geoserver WMS. I set the raster layer's geographic coordinate system as the same as the cloudmate tiles. ...
3
votes
2answers
292 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 ...
1
vote
0answers
253 views

Raster satellite images for QGIS

When I try to apply a downloaded GIS satellite (t=rimage to Quantum, it doesn't seem to open properly. There must be a step-by step description on how this would be done effectively. Can anyone tell ...
3
votes
1answer
759 views

How to align two rasters of exact same cell size, extent in ArcGIS 10?

I have two raster datasets. One is already georeferenced. The second one is not georeferenced but should have the exact same extent and cell size as the first one. It is supposed to exactly overlap ...