Rasters are regular grids of values, usually stored in an image-like format.
0
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0answers
27 views
Isolate And Save Raster Features From Existing Multivalue Raster Map
I have Cyprus Corine map with 44 different types of land use.
I want to run a raster calculator query or any other way to isolate the areas with codes 10 to 22 and 26 to 34, all other values 1 to 44 ...
0
votes
1answer
108 views
How do you use 'reclass' in GRASS?
It could be user error, but for some reason, the reclass tool is just hanging and hanging...
QGIS 1.8
Compiled against GDAL/OGR 1.9.2
Ubuntu 12.04.1
Running the tool from the Sextante toolbox
Input ...
0
votes
1answer
52 views
Sextante (SAGA) “Normalisation” problem
I don't understand the SAGA-module "NORMALISATION". In SAGA Gis I just can define one MIN and one MAX value. In QGis I have to define 2 of both. How to handle that exactly?
3
votes
4answers
95 views
Combining UK OS Historic Digimap Tiles
I'm assisting a retired user in combining a large number of raster tiles downloaded from Historic Digimap http://edina.ac.uk/digimap/description/historic_overview.shtml into one project in qgis.
I'd ...
4
votes
2answers
103 views
How to create a colormap where colors diverge at value 0 in QGIS?
I calculated a raster as difference of two other rasters. Now I want to create a colormap where one colour represents negative values and one colour positive ones. The two colours should become ...
0
votes
2answers
147 views
Digitizing from OpenLayers Plugin in QGIS, or create raster?
Is there an easy method for digitizing from a layer added from the OpenLayers pluggin. As i cannot snap to it or use it as raster so the entire map does not load?
two separate issues there.
3
votes
1answer
69 views
Difference between gdal versions in reading raster on two machines?
I am using raster data from Afripop.org and using the R package raster (raster_2.0-41) to do all my computation. Everything has been working out just fine until I tried sending some jobs to a remote ...
6
votes
1answer
69 views
weighted mean across rasters in R
I have 2 rasters. One raster (bio1) contains temperature information across a continent. The other (sp) contains, for each cell, a probability of occurrence for a species. I would like to calculate ...
3
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0answers
198 views
How can you convert a Rainfall Isohyet map into Raster so you can determine the precipitation (mm) at any point?
I'm Joanne & I'm a newbie in ArcGIS... I Hope somebody can help me figure this out:
Specifically, I have a rainfall map (Isohyets) measured in mm (precipitation)... I wanted to know a particular ...
1
vote
1answer
632 views
reclass, raster calculator
I'm trying to apply seperate equations for different land types. I have created a raster containing only the land type I'm interested in. I then reclassed the values to '0'. My plan was to use the ...
1
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0answers
47 views
How to clip Raster using multiple polygons and Python? [duplicate]
Possible Duplicate:
clipping a raster by multiple datasets or polygons
I have polygon layer and DEM and I want to write a program using python to cut the raster into multi-raster based on ...
1
vote
0answers
52 views
How I can incorporate results of histogram stretching into georeferenced image?
I have one channel 8 bit raster and when I open it in QGIS with histogram stretching "on the fly" it looks fine. How I can recalculate original raster accordingly changed histogram?
1
vote
2answers
127 views
Why is Format of output data grayed out on Save As dialog for Rectify?
I started georeferencing and I could not save my new "rectify" file, I don't know if is because of the raster or I did something wrong. Then I find out that my control layer is not accurate, it ...
3
votes
3answers
202 views
How to extract raster values and create new raster in Qgis?
I want to extract certain values of a raster image in order to create a new raster which then should only contain the extracted/chosen values.
How to do this in QGis?
4
votes
1answer
116 views
Add band to existing GeoTiff using GDAL
This seems like it should be straightforward but I can't for the life of me figure it out.
Given an existing GeoTiff containing a single band, how can you add another band to that GeoTiff? Is the ...
3
votes
1answer
78 views
ArcGIS Raster Symbology - Break contour at 0
In ArcGIS 10, how can I break raster symbology (stretched) at a particular value (i.e. 0). For example, I have a DEM representing both topography and bathymetry and I want a break at the 0 m contour ...
6
votes
2answers
136 views
Breaking apart a polygon layer by unique values, creating many new layers
I have a large dataset of habitat information that I need to calculate distances from animal locations to the closest polygon of each habitat type. The way to do this, that I understand, would be to ...
1
vote
2answers
83 views
Put color for raster data(aspect.tif) on QGIS1.8.0
I create aspect.tif from DEM file.
I could put the values(0 to 360)from contrast enhancement.
I could set color from color map(freakout or Pseudocolor).
In here, the data is shown by only 4 colors.
I ...
1
vote
0answers
103 views
How to use GDAL to burn a selected value from one raster into another?
I think this should be a relatively simple process, but I'm not quite sure how to approach it.
I have a shapefile containing 1000's of polygons. I also have 19 rasters. All of the polygons fall ...
2
votes
1answer
38 views
How to visualize the water equivalent between two raster layers in arcmap 10.1?
I do have two raster layers (interpolated with Empirical Bayesian Kriging), that show the elevation of a glacier in April, and September. I want to show the change in elevation between the layers in ...
4
votes
1answer
68 views
Why does the added raster layer have strange edges?
I'm using Geoserver in conjunction with the google maps API to add a raster layer onto a map. It loads fine, however there's some strange problem with opacity at the edge of the layer where you can ...
1
vote
0answers
132 views
Importing grib, grib2, netcdf to PostGIS
According to grib2 to raster? (grib2 -> raster2pgsql -> PostGIS 2.0 -> GeoServer), it seems like that grib2 can be treated as raster directly. Is it the so called "standard" way?
How about ...
1
vote
2answers
62 views
ArcPad Raster Not Displaying Correctly
I have a hillshade that I would like to use as a background in an ArcPad 10 map. I get everything set how I want in in ArcMap and when I export the map to use on my Trimble the hillshade doesn't show ...
1
vote
1answer
47 views
cannot print listRasters
I'm trying to run this very simple script to check a problem in another more comlpex one.
import arcpy
arcpy.env.workspace= 'C:\\Users\\Umberto\\Desktop\\Prove_Script\\Karakoram\\temporary_01'
rst= ...
4
votes
2answers
190 views
How to extract values from a raster according to Lat and long of the values?
having 12 files with 12 hdrs for one year: these files are raster (projected WGS84,lat long):https://echange-fichiers.inra.fr/get?k=rLSyoavrnifGyH5XrlO
samples = 1440
lines ...
4
votes
3answers
68 views
Where can I find decadal climate and ocean data for Europe?
I would like to find decadal climate and ocean data for Europe that I can download and use directly in ArcGIS. Specifically, I am looking for mean annual temperature, sea surface temperature, and ...
5
votes
1answer
69 views
What GIS software is required to export a GIS map as a hi-res raster image?
I am looking for some (preferably free) GIS software that will enable me to export multi-layered world maps (made up of shape-files and kml files and so on) as hi resolution (21,000 pixels wide), ...
0
votes
0answers
17 views
Aggregation operation on raster files inside a raster database in postGIS Raster
I have a raster database in PostGIS Raster. I want to merge a number of raster files that are imported to the database using average to create another file. In the other words, the mean value of ...
1
vote
1answer
86 views
How to add multiple rasters to a layer file?
I'm trying to make a .lyr file to bring into ArcMap with arcpy.mapping. I can bring a single raster into a .lyr with the script below. I'm unsure how to proceed to get multiple rasters from the same ...
2
votes
2answers
219 views
How to georereference a TIFF file which has already a spatial reference?
I have a TIFF file of Poland and a self drawn vector map of Poland. The vector map has no spatial information.
I am intending to reference the TIFF exactly to the shape of the self drawn map.
My ...
4
votes
1answer
121 views
Use csv file as raster file and stitch them together
I'm having an issue trying to stitch together 100 32bit Tiff files (coming from thermal imagery video and extracted as 32bit Tiff).
I used Hugin to mosaic the pictures extracted from the video which ...
3
votes
0answers
111 views
shortest distance between a raster and another raster
i am using arcgis 10.1
i want to calculate the shortest distance between a raster and another raster. i have a bathymetric raster and an underlying fault plane raster. for each bathy raster cell, i ...
4
votes
1answer
134 views
How can I avoid reprojection gaps when merging DEM rasters?
I have two raster DEMs in same resolution I want to bring together. I was using the merge-function in SAGA, GRASS and QGIS but I always get the following result:
What do I need? Where could the ...
1
vote
2answers
296 views
QGIS Raster Calculater Syntax
I am trying to use the raster calculator in QGIS to combine a number of rasters. I want to calculate a mean, this is easy:
(raster_1@1 + raster_2@1 + raster_3@1) / 3
I then want to create a max. ...
0
votes
0answers
133 views
Output of QGIS raster clipper not as expected?
My goal is to clip a raster with a polygon in QGIS 1.8. Based on an article I read, this should be a pretty straightforward task. However, the output appears to be empty. The raster produced is the ...
1
vote
0answers
148 views
Raster calculator error 000539 - cannot create weak reference to 'classobj' object
I was - like many times before - trying to clip a raster with the raster calculator (raster * 1 with shapefiles as mask). Now - the following error keeps popping up:
ERROR 000539: Error running ...
3
votes
1answer
62 views
Get rid of raster grid cells that are less than 1
I'm using QGIS to work with raster data. I have a raster dataset of a country where each grid cell is assigned a number 1-100. However, the raster is in the format of a rectangle based on the extent ...
6
votes
1answer
91 views
How to reclassify raster data by their sign?
I want to do the following: I have two data raster sets with different units and values. One results from measured metric data, the other from modelled grid values. What I want to compare is simply ...
3
votes
0answers
58 views
Geoserver Raster layer cropped by polygon?
I've got a Geoserver raster layer which represents a satellite image. I use the Geoserver WMS to display the raster in OpenLayers. I want to display only parts of the raster - those within a certain ...
0
votes
0answers
68 views
Can't Find Raster with Android QGIS [closed]
I can't seem to use QGIS android file system to find input files on my xoom. I have stored Alaska raster on both sdcard and sdcard2, but I can't find it with QGIS.
I managed to solve this problem ...
0
votes
0answers
211 views
How to resample a raster in QGIS?
I've got a boundary file that I would like to resample the raster file from a 30m grid to a 10m grid inside the boundary file. When I try and do it in Qgis or Grass all I get is one big raster cube ...
7
votes
2answers
177 views
How to create a solar intensity map for a garden plot?
I'm interested in creating a raster surface that depicts the average solar intensity per unit area for a small garden plot. I imagine the inputs into the model would be the following:
Plot ...
1
vote
0answers
26 views
When a raster is described in general as either a double or an integer how do conversions work for that type
I know a raster format is essentially a grid of cell values that may have values associated with color, but I'm unsure of how the primitive types factor into the format. In addition if I need to write ...
3
votes
1answer
280 views
How to re-project ease( Equal Area Scalable Earth) grid with a ~25 km cylindrical projection to WGS84 0.25 degree?
I have nc (NetCDF) files for global soil moisture.
From the metadata, the projection is cylindrical and the resolution is 25 km (it is based on authalic sphere based on International 1924 ...
1
vote
1answer
57 views
How do I create rendered vector field in qgis
Perhaps I am misunderstanding the "vector field renderer" and "VectFieldCalc" plugins, but I have no idea how to make a vector field of arrows, with directions and magnitude. I have the data loaded ...
6
votes
2answers
144 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
0answers
75 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
55 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
74 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
vote
3answers
61 views
Apply 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 ...
