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

learn more… | top users | synonyms (1)

1
vote
0answers
22 views

Is there any GRASS command to measure the distance between a point in rastermap and another in vector map?

I have a question about WinGRASS 6.4.3. Is there any GRASS script command to measure the distance between a point in rastermap and another in vector map? I have a raster map and a vector map. Raster ...
0
votes
2answers
34 views

Polygon Data to Fit Raster

I'm working with an NHD Flowline of streams and rivers in NC, and I'm trying to only retain the ones in the raster. I tried to convert to the raster to a polygon and was going to clip them, but in the ...
0
votes
0answers
19 views

What information, Open Attribute table of stream segment shows?

I have delineated the watershed from DEM data. I have converted the stream segment(raster) to vector lines. In the attribute table of this vector lines, there are 3 columns, CAT, VALUE, LABEL, what ...
-1
votes
2answers
62 views

Polygon shapefile to Raster with Mask and Extent

I have a polygon shapefile (Vesijärvi lake). The lake has many islands, bays and inlets. When I look at the attribute table, there are actually two adjacent features: Northern lake and southern lake. ...
1
vote
1answer
61 views

Extracting data from a raster to a polyline based on start and end points?

I have a polyline shapefile with the attributes seen above. startx and starty represent the coordinates of the beginning of each segment of a polyline. endx and endy represent the coordinates of ...
1
vote
1answer
38 views

How to perform a standard deviation stretch on a raster in QGIS

Is there a way to perform a (2) standard deviations stretch on a raster image in QGIS 2.2? I have found the raster styles menu, but the help says there is no help in my language (English) and whilst ...
0
votes
1answer
16 views

Is rid=2 significant in PostGIS raster structure?

It seems that in most, if not all, examples with raster appear to include the WHERE rid=2 statement in the query. http://postgis.net/docs/RT_ST_Value.html Is there something about the rast structure ...
0
votes
4answers
89 views

Best tutorials on raster data formats and raster manipulation [closed]

I am looking to improve my understanding of raster formats and how to manipulate them. I don´t really want to go into the mathematics of it, but really want to know the differences between the ...
1
vote
1answer
47 views

QGIS Quickly switching overlapping raster images

I'm new to QGIS, and haven't used arcGIS in about 5 years, however I've just seen someone using arcGIS and was able to quickly switch between overlapping rasters when checking registration. The top ...
0
votes
1answer
24 views

Convert a KML ImageOverlay to World Files with GDAL

I have many raster outputs from an Open Source radio transmission topographic path tool called SPLAT, georeferenced in KML image overlay format. I have figured out an easy way to use tools to ...
0
votes
1answer
39 views

Merging Raster: ImportError: No module named _gdal_array

When I try to merge rasters I got following error message: _gdal_array = swig_import_helper() File "C:\PROGRA~1\QGISDU~1\apps\Python27\lib\site-packages\osgeo\gdal_array.py", line 18, in ...
1
vote
1answer
53 views

Floating point calculations in QGIS

How do I manage floating point calculations in QGIS? I have carried out 3 consecutive calculations on landsat bands. I end up with 32 bit floating point rasters on which I can't carry out a 4th ...
0
votes
0answers
31 views

How do I select specific colors within a raster to create polygons with in QGIS or ArcMap?

We have a few georeferenced zoning map rasters and would like to convert specific zones (colors) to polygons, sometimes multiple zones as different polygons. Our workflow has been in the past to ...
2
votes
3answers
79 views

How to reclassify only a part of a raster but keep the rest unchanged (ArcGIS or R)

I'm trying to reclassify only a certain part of a raster...not the entire raster. Here's the problem. I have a LULC raster of the entire US. There are some issues with the raster that I want to ...
1
vote
1answer
56 views

What format to store/use four band Raster data

I have four band aerial photography - RGBI. I need to share it with my users, a mixture of MapInfo, QGIS, and ArcGIS. What format should I store/serve the data in? GeoTIFF isn't well suited to four ...
0
votes
2answers
100 views

Why am I getting 'Error 000732 Raster does not exist'?

I am trying to apply symbology to a raster layer via kernel density analysis. When I run the Python script below in ArcMap, I am get the error message below. I have searched and tried the common ...
0
votes
1answer
67 views

Create Tiles for a raster(georeferenced) to use in leaflet

I have raster, with each pixel containing some data. What i want is to split a large image with each pixel's color is determined by its value, to show on leaflet layer.How to go about this ? raster ...
1
vote
2answers
103 views

How do I open images georeferenced in ArcMap in QGIS? (.aux.xml)

We have several ArcMap georeferenced images (raster datasets) that we are attempting to open in QGIS without any luck. These are not inside of a geodatabase and are not Arcinfo Binary Grid format or ...
0
votes
0answers
31 views

Why does heatmap size vary with number of points

I am making three heatmaps based on points over the same area and don’t understand why the number of rows and columns would vary depending on the number of features. The first feature set has 398 ...
1
vote
0answers
36 views

Extra row and column in a raster after GDAL grid import

I'm exporting an ESRI grid to TIFF format and after that I'm reading this exported raster file into SAGA GIS. However when Saga reads this file in there appears to be an additional row and column in ...
3
votes
0answers
104 views

How to compute surface of raster or any point using ARCGIS?

I have a raster image whose values are a digital elevation model of terrain. I need to know the surface type (topographic characterization) of particular points along transects of this DEM. How to ...
2
votes
0answers
57 views

Move Scale Rotate raster in Qgis

I have some archaeological scanned raster that they have a north arrow and a scale bar. There is no grid, no coordinate system.I would like to put those files in a general map. I don't care about the ...
1
vote
1answer
56 views

ArcScene TIN smooth

I created a TIN with ArcScene out of laserscan point data. I want to smooth the spikes (image below), to get a nice crossover on the elevations of the surface. Do you have any advice how to do that? ...
0
votes
1answer
37 views

Export raster file geodatabase to jp2 or jpeg?

Can I export or copy a raster from a file Geodatabase and create a output to jpeg or jp2000 formate? I was reading two different helpline on ArcGIS 10.1 and wasn't sure if I was supposed to export ...
0
votes
0answers
11 views

Raster images at edge of data frame not displaying. How can I prevent then from disapearing?

I have a series of satellite images and as I pan or zoom, the images near the edges of the data frame the stop being displayed leaving small areas with no imagery. It is seems to occur when only ...
2
votes
1answer
44 views

How do you stop ArcGIS setting Gamma on raster load

I often import raster files using GDAL utilities. When those rasters are added to ArcGIS they seem to have a Gamma Stretch applied and a percent Clip stretch for RGB files. Contrast ids also set to ...
0
votes
0answers
27 views

Zonal statistics won't work after re-projecting vector layer

I have qgis 2.0. I want to analyze raster information within a buffer of 30 miles around a vector layer of cities across the world. However, both the raster and the vector are in WGS84. I have no ...
3
votes
3answers
87 views

how to digitize areas of a raster and snap to the raster cells?

I need to digitize the extent of an ecw raster image where the RGB value is not black.(see attatchment)ie. not the envelope, just the area where the image is shown without the border areas. The black ...
1
vote
1answer
56 views

Why am I losing part of my raster when I reproject?

QGIS 2.0 Working with tiff raster file. Reprojections are in WGS84 Mercator. Here is my problem: I am trying to use buffers or urban areas to analyze light intensity on a raster layer. I want 30 ...
2
votes
1answer
62 views

How to best remove rgb values outside of aerial image?

I have just converted RGB-TIF images to RGB-ECW for reasons of space and performance in ArcGIS. However, after the conversion, there are relics outside of the images which are not nodata values but ...
2
votes
1answer
89 views

How to iterate GRASS region definition?

I am using GRASS r.skyview command (v.7, Windows) to determine "urban canyon effect" on pollution due to the presence of buildings. The command nicely works, unfortunately I need to process a very ...
1
vote
1answer
78 views

Multiply a raster list with a field value list in a FOR loop in ArcPy

I'm trying to create a simple map algebra calculation not managed by ModelBuilder, but writing it in Python is trickier than I thought. I have a list of raster in a GDB and I must multiply them by ...
1
vote
2answers
51 views

How to import R-generated .gri/.grd raster files in grass?

I received data in .grd + .gri format, where the first one is a small text file and the second one (having the same name) is a binary file. I am unable to open them in grass/qgis. Any hint ? Missing ...
1
vote
1answer
104 views

Clip raster layer with *raster* mask layer in QGIS

Given two input layers 1. The clip layer - an arbitrary layer (though in my case it's a float 1 band geotiff) 2. The mask layer - a paletted raster in which every pixel is either NO DATA or a single ...
1
vote
2answers
88 views

How to summarize Excel data within the zones of another dataset by using ArcGIS 10.2

I have the following Excel data, I want to summarize the P-value within the zones of map dataset. I have sereached a lot and learned I might need to convert Excel data into XY table, and then into a ...
2
votes
1answer
70 views

How can I rasterize individual features in a shapefile?

I have a large number of polygons that are overlapping. I'd like to create a heat map and plan on using raster calculation to do this. My plan: to give each polygon a raster value of 1, and adding ...
2
votes
1answer
140 views

Calculate the values of range, sill, nugget in ordinary kriging? [closed]

I am working on temperature data, and I want to interpolate the data to any location that I specify. My programming language is asp.net4 C#. I don't know how can I determine the sill, range, nugget ...
3
votes
1answer
28 views

Specify single cell value of raster

I'm looking to automate a procedure that will change a single cell value in a raster. I have a known x, y and z, and a raster. I need to change the cell value (closest to my x and y value) to the ...
1
vote
1answer
25 views

display 3D raster/vector in GRASS 7.0 from command line

I am using GRASS 7.0 on ubuntu linux 12.04 x64. I am working through some GRASS tutorials and am able to get a 3d raster to show up when I use the GUI. However, I cannot get the command line interface ...
0
votes
1answer
72 views

Polygonize(raster to vector) [closed]

I have been install QGIS 2.0.1.when I use Polygonize (Raster to vector)for convert jpg to shp I get error message such as: C:\windows\123.exe is not recognized as an internal or external ...
0
votes
1answer
36 views

Building attribute table from raster in ArcMap 10.1

I have a NetCDF file containing the latitude, longitude and porosity for the entire US. I am trying to add another value (wilting point) which depends on the porosity. I wanted to extract the netcdf ...
0
votes
0answers
36 views

Dates are off when opening netcdf file in R

I have a netcdf file with the time dimension that goes from 12/2007 until 12/2010 with monthly time steps. I can see the correct dates in both arcgis and panoply. Panoply tells me this file is a ...
0
votes
1answer
86 views

Cannot read postgis RASTER into ArcGIS using the interoperability extension, either directly by Query Layer

This post accessing postgis raster data using Query layer in ArcGIS was created in Jul-12. Since then, I have not found any other related-post published. Using QGIS with DBManager ON, my postGIS ...
0
votes
1answer
63 views

How to load Georeferenced Scanned Maps in R

I have a geo-referenced scanned Map in GeoTiff format, which I would like to load into R. My intention is to plot some vector data (points and polygons) over this map using maptools package. Is ...
1
vote
1answer
63 views

Cannot upload an IMG file into PostGIS using raster2pgsql

I cannot upload into PostGIS a raster with the following code: raster2pgsql -s 4326 -I -C -M "C:\lyr\gebco.img" -F public.gebco ¦ psql -d test -U postgres -W It says ERROR: Unable to read raster ...
2
votes
0answers
59 views

How to display images as cross sections in 3d

I want to display a base map and several vertical cross sections in 3D. The base map image is easy to rectify as a geotiff. How can I also display the cross sections? The cross sections are at ...
0
votes
1answer
14 views

How do you distribute values evenly within zones when converting polygon to raster?

I'm trying to convert a (traffic analysis zone) TAZ polygon to raster so that the population values are evenly distributed within each zone. So far, when converting the TAZ polygon, the same ...
0
votes
2answers
43 views

how to specify -t critical dowloading raster with raster2pgsql

I'm trying to download a raster into postgres/postgis. So far I wrote: raster2pgsql -s 3006 -I -C -M -R filename.tif -F -t 463.313x463.313 schema.rastername | psql -h localhost -U postgres -d db ...
0
votes
0answers
15 views

How to obtain stream segments from complemented image(raster data)?

I have raster data in tiff format, i want to extract stream segments from the complement of original raster data. I am able to extract stream segments from original raster data, but not able to ...
2
votes
1answer
39 views

does Pseudo Mercator Projection causes problem while clipping rasters

I tryed to clip a Raster file using an ESRI shapefile using gdalwarp command, but i always get an empty output file or a wrong clip with wrong location. this the command bellow: gdalwarp -dstnodata ...