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

learn more… | top users | synonyms (1)

0
votes
0answers
25 views

Disable option in QGIS which picks 4th band as alpha band

Is there a way to disable that function? As somebody who works with 4 band orthoimagery on a daily basis, it is annoying to go to the transparency options every time I load an image to disable the ...
0
votes
0answers
21 views

Slope regions from elevation points using QGIS 2.0

I am using QGIS to create a layer of slope region polygons (e.g. less than 30% slope, 30-50%, more than 50% categories). My data comes from point elevations and I interpolated using SAGA b-spline ...
0
votes
1answer
21 views

DN value from raster to vector tool (QGIS 2.0)

I am using QGIS 2.0 to convert a DEM to vectors, then create polygons of zones of slopes. However, I am unsure of in what units my new "DN" column is. It has lost of precision of z-values from my ...
1
vote
0answers
36 views

Is it feasible to reclassify a raster which has been resampled/smoothed for display purposes?

Background: I have a Google Earth KMZ file which shows ground movements after an earthquake, arranged into discrete classes: From the KMZ file I'm able to download the original PNG images, which ...
0
votes
0answers
22 views

rasterize a geography polygon using postgis 2.1

I am still bit new to Postgis 2.1. I am trying to rasterize a polygon, meaning that I have a polygon of Syria and I want to create an empty raster that contains the shape and geography reference of ...
2
votes
2answers
100 views

Calculate Slope Between Pixels Through Time: A Time Series Trend Analysis

I have a 9 year weekly time series (~500 raster grids of equal cell size and extent). I'm interested in obtaining the regression line slope between pixels (Imagine stacking all 500 grids on top of ...
2
votes
0answers
64 views

Ecoregions shapefiles: subsetting, extracting and summarizing data from raster

I am attempting to subset and project an ecoregions shapefile from : EPA ECOREGIONS my data set is found here: SHAPEFILES and RASTER When I run this code, two major problems occur: 1) I cannot get the ...
5
votes
1answer
199 views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
0
votes
0answers
65 views

Issues creating slope raster layer from a point layer

I'm trying to create a slope raster layer using QGIS 2.0 on Windows XP. I started with a points layer with the Z elevation attribute. I then used the interpolation plugin to create a DEM. But, ...
1
vote
1answer
55 views

Need to calculate values for a cell based on surrounding landscape

I have a raster file with the urban development of a county mapped out (values: 1=urban 0=not urban). I also have a raster file with several blocks of forested land, each block of land has its own ...
2
votes
1answer
27 views

Raster Calculator Syntax - ArcGIS

I'm trying to reclassify a raster based upon two criteria 1. Raster cell on "CBH" is less than or equal to 2 AND "footprint" is not null. Then output raster reclassifies any cell inside this criteria ...
1
vote
2answers
111 views

Replacing raster values in one raster with another raster in QGIS … how to?

I have a raster (DEM) and want to replace a few cell's values with the values from another raster in QGIS. I would have done this with the "over" tool in the raster calculator in ArcGIS. Specifics: ...
0
votes
1answer
21 views

Which format is more convenient to publish in Erdas Apollo?

I am from Bolivia and I need to publish some Satellite images in Erdas Apollo. My question is Which format is more convenient for publish in this software?, because I have Landsat5 TM images in TIFF ...
1
vote
0answers
30 views

MapServer: UV_ANGLE not calculated correctly?

I'm following this example given on the MapServer website. But the angle of the raster is incorrect: The data is my grib files is correct, and should not yield these perfect opposite directions. ...
1
vote
2answers
59 views

Minimum mapping unit for raster on ArcGIS

So I have this huge national wetlands raster and I'm trying to set a minimum mapping unit of 5 acres. Meaning I want to delete clusters of pixels that are smaller than 5 acres. But the raster's ...
0
votes
1answer
73 views

Iterative raster calculation script using NumPy arrays breaks after ~10 rasters, returns: “TypeError: Cannot create raster for numpy array.”

Here is my code: #Generate Cumulative Thresholds #5/15/14 import os import glob import arcpy import numpy as np #Enable overwriting output data arcpy.env.overwriteOutput = True ...
0
votes
2answers
82 views

Change detection with raster calculator

After applying the Diff operator of the raster calculator in arcgis to view changes in land use, would like to see the areas of increased and areas of decreased. This is possible using the raster ...
0
votes
0answers
15 views

extracting values from maps and inserting into a summary table

I have several maps that I am working with. I want to extract the values (1, 0 and NA) from the maps and place them all into a summary matrix. Since I have so many maps, I think its best to do this as ...
0
votes
0answers
31 views

How to draw rotated symbol RASTER type layer in Mapserver?

[PARTIALLY SOLVED]: I was on the wrong track I need to use a UVRASTER, see this part of the docs But doing leaves with with another question about how to get the angle correctly, please see this ...
1
vote
1answer
65 views

Raster calculation in for loop returning exit code -1

I've put together a python script that does some calculations on rasters by converting them to NumPy arrays, doing the math, then converting them back to Raster and applying all the same spatial ...
0
votes
0answers
46 views

How to get RasterToPolygon working

We have a process that is almost working except for this one call ... This is the one tool function that is requiring a FeatureClass and I found code that I thought would work. Unfortunately all I ...
0
votes
1answer
31 views

Passing RasterDataSource object to RasterData object in Javascript API?

I have a GP service that requires a RasterData object as input. The RasterData object should hold a RasterDataSource object, but I'm not sure of the syntax to connect these two classes. The API ...
0
votes
1answer
29 views

Display Background Value as hollow, for more than one set of RGB values

I have two overlapping .ecw layers of the same area, though one is clipped in the middle, with a white edge. When I set the background value to 255,255,255, and define it as hollow, it only hollows ...
1
vote
0answers
48 views

PostGIS raster connection is not closed by MapServer

I'm using PostGIS raster in MapServer like this: TYPE RASTER DATA "PG:port=6432 dbname='mydb' user='postgres' password='1234' schema='public' table='truemarble' mode='2'" PROCESSING ...
0
votes
0answers
26 views

R equivalent of GRASS r.grow?

What is a good R equivalent of the GRASS function r.grow? The closest I've been able to find is the script suggested by whuber in response to Creating randomly shaped clumps of cells in a raster from ...
2
votes
1answer
41 views

Identifying X-Y coordinates from a raster

I need to find the high and low values of multiple raster datasets individually. Then determine the x,y location of these values. I am using ArcGIS 10.1, have built the mosaic datasets I need, and ...
2
votes
2answers
113 views

Nested loops for raster calculation arcpy

I am trying to figure out a way to input corresponding raster datasets from two separate folders into an equation using arcpy. I think it requires some sort of nested loop but I can't figure out how ...
0
votes
1answer
40 views

Multiply point values by raster values

I have a point shapefile containing elevation values in the id field. The shapefile is overlaying a raster layer of the topographical slope. Is it possible to multiply the elevation value of each ...
1
vote
1answer
69 views

Rasterizing polyline data with QGIS/GDAL: custom line width

I need to make a raster from a polyline shapefile. However, when I use gdal_rasterize (either directly or through QGIS), all my lines are drawn one pixel wide, while I need them to be drawn with the ...
1
vote
1answer
31 views

Improve display of fine resolution raster

In the above map, I am showing yields on some parts in Iowa at a pixel resolution of 100m. However, in this case due to the relatively small number of pixels (and high resolution), the map is not ...
0
votes
0answers
33 views

Assign a particular projection for un-projected raster/vector files in a folder/sub-folders

We are having 1000's of raster images/vector (shp,tab,dxf) files in a folder/sub folders. Is it possible to check the projection of those and if it is an un-projected one? WGS 1984 has to be ...
0
votes
0answers
36 views

QGIS 2.2. raster color ramp

I have just upgraded from QGIS 1.8 to QGIS 2.2 and I am missing very much 1-band raster color ramp plugin that I had easily colorized my DEMs by using pre made color brewer such as DEM screen or DEM ...
0
votes
1answer
50 views

How wrap GRIB data in Mapserver 6.4

I'm trying to draw a combination of layers with Mapserver. One of the layer takes a shapefile as input and the other one is based on GRIB data. The issue is that the GRIB layer (in green) is drawn ...
0
votes
1answer
29 views

json issue: GetFeatureInfo with raster images

I have succesfully typed a GetFeatureInfo request with the following structure directly into my browser: ...
3
votes
2answers
77 views

How to query DEM elevation values in a web application based on cursor/click point location?

I work for a city government that has LiDAR derived DEM rasters which we would like to make accessible to other departments in the city. The problem is that many departments don't have anyone with ...
0
votes
1answer
34 views

How do I convert coordinates to raster (bsq, bil) lookup?

I have a .bil file, which has interleave = bsq in the hdr file. I'm having trouble finding any insight into how I would essentially do a lookup on the file. I have no problem reading a specific ...
1
vote
1answer
87 views

Is there a way to remove this thick gray border from my raster symbology in the legend?

I have this problem with different raster layers, in this instance it's land use data. In my layout, and in a rendered PDF of my map, the legend entry for the raster layer has an ugly, thick gray ...
0
votes
1answer
24 views

Unable to get processing extent to match desired raster output

I have a few thousand ortho mosaic tiles that I've resampled to a lower GSD and am trying to cut into larger tiles. I developed a script that has worked perfectly for thousands and thousands of tiles ...
0
votes
1answer
31 views

Is there an easy way to refresh / update a raster tif file in GIS?

Apologies for the newbie / basic question, but it seems to be a fairly simple concept which I can't get to work properly, and I'd be really grateful for a pointer or two! I have a load of different ...
1
vote
0answers
26 views

Import raster to postgis and add a foreign key constraint

I use raster2pgsql to import raster files into a table with this command line: C:\Program Files\PostgreSQL\9.3\bin>raster2pgsql -s 4326 -M -F -a c:\temp\mun.tif public.basqui_raster | psql -U ...
0
votes
0answers
22 views

glm with raster data: species decline~ ndvitrend

I have species decline data (number of population per year, over a period of 23 years) out of ndvi data for these 23 years I calculated the trend, and mapped it. now i'd like to relate the negative ...
1
vote
1answer
55 views

How to display raster attributes by default?

I have a 4-bit thematic raster image with a color map from white to dark blue (Figure 1). The values 1 - 6 represent tree canopy cover at various breakpoints. I also created a raster attribute table ...
2
votes
1answer
33 views

Setting Point Cloud Data Colour from Raster

I was reading this article: http://blog.safe.com/2013/10/14-ways-to-take-charge-of-lidar-data/ Number 12 states that you can change the colour of your point-cloud data by using a raster image. Does ...
1
vote
1answer
58 views

How to export a Raster attribute table into a .txt using Model Builder

I'm using ArcGIS 10.1 I need to export a Raster attribute table into a .txt (or any other format Excel can import), using Model Builder. Is it possible?
1
vote
1answer
25 views

How to build attribute table from raster .tiff in ModelBuilder?

I have built a model that goes through a folder of raster files (TIFF), calling each time one file and running a routine. The problem I am facing is that imported raster files do not have an ...
1
vote
0answers
19 views

Finding the best way to prepare raster image for a function in R

I'd like to ask what is the best way to prepare big raster images in R to run a function on whole images. I have 30 tiff images with the size of ncol=12648, nrow=4144. I read them in R separately. ...
0
votes
1answer
57 views

Setting a value on a raster where a polygon intersects cells

I reviewed all of the supposed 'answers' and I just do not see that they really answer my question. Mostly because the ones I'm reading are setting values either inside or outside a boundary. So let ...
2
votes
1answer
80 views

Running Random Forest Classification on WorldViev-2 image in R - problem

I have a problem with performing RF in R for a WorldView-2 Scene. I've never ever before used R for remote sensing classification, so I simply followed what is written here. I've loaded scene (8-band ...
0
votes
2answers
56 views

From RGB raster to grayscale

I have been searching for a way to rasterize shp files (Unexpected output when using gdal_rasterize) and it worked with a little help. Now, my code is first rasterizing the largest sip file and than ...
1
vote
1answer
54 views

Unexpected output when using gdal_rasterize

Ok, I used the following code for converting my layer into raster format but I get a tif file that is completely black or white... from osgeo import gdal, ogr # Define pixel_size and NoData value ...