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

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743 views

ListRasters not recognizing raster files in python

I have 2 rasters in my workspace, one in TIFF Format and the other in GRID format: "C:\ExampleFolder" When I use the python script: import arcpy >>> rasl=arcpy.ListRasters("C:\ExampleFolder"...
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1answer
915 views

Error in raster displays of NoData cells when “zoomed in” past scale 1:3,000,000

I looked around GIS stack exchange and ArcGIS Help pages and didn't find anything on this issue. I have encountered an error in how Arc displays a Raster file (.TIF format) at different scales. At ...
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1answer
527 views

How to calculate size of a pixel for a scanned map?

A land use map has a scale of 1:150000. The map is scanned at a resolution of 150 DPI. What will be the surface area in m square represented by each pixel in the resulting easter map?
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1answer
312 views

Why does Save as “Rendered Image” change the raster styling?

Rasters exported from QGIS (via Save As > Rendered Image) do not retain original styling. See attached. Any thought on how to prevent this error? The top image is exported from QGIS as a .bmp, the ...
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2answers
84 views

View an .ecw-file in QGIS 1.8.0? [duplicate]

I have got a .ecw-file that I want to somehow import into QGIS 1.8.0. Is there a plugin that I can install that can help me do this or is there another way? The .ecw-file contains rasterdata.
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4answers
4k views

Clip raster using shapefile into multiple rasters using ArcGIS Desktop?

I have a raster file representing a large area and a shapefile of 30 polygons representing watersheds. I would like to clip the raster with the shapefile to create 30 rasters representing each ...
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2answers
307 views

gdal_grid has some problem with reading vrt file

I am using gdal_grid module(from gdal 1.10) and it has some problem with reading the vrt file. I checked this link but it does not work. gdal_grid problem reading vrt file The command is ./...
0
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1answer
392 views

Topo To Raster executing but not creating the raster

I am using Topo to Raster by File (ArcGIS version 10.1) via arcpy on a large stream and point dataset. Arcpy runs fine and executes without issuing any error message, however it does not create the ...
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1answer
111 views

Attribute names being truncated during extraction

I have 30-40 raster layers and each raster has approximately 40 columns. The attribute/column names are very long, and the beginning of each column name is the same. During the extraction process, ...
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1answer
1k views

Converting a raster to a polygon

I need to convert a raster into a polygon, and I ran into "Error 000863: Invalid GP Data Type" After searching, I saw this solution online. Basically I needed to convert the float raster to an ...
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3answers
169 views

ArcGIS - ModelBuilider - Collect Values not working as expected

I am trying to iterate through a folder of rasters, reclassify each raster, then combine all of the reclassified rasters using Cell Statistics (to get the overall SUM of the reclassified rasters). I ...
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138 views

Write raster with its attribute table and symbology

I am classifying lots of rasters and I'd like to automate the legend creation and symbology displaying for easy manipulation. Here is the kind of raster I'm dealing with: library(raster) r <- ...
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2answers
1k views

How to change raster cell values within a polygon using QGIS GUI?

I would like to know how to change the values of raster cells which are within a polygon, leaving all cell values outside the polygon unchanged. I would like to subtract 1.5m from each raster cell ...
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2answers
383 views

QGIS howto create raster from map canvas easily

i have question ho to create raster from QGIS map canvas (what i seen in my qgis) easily. Now i have used print composer and after some luck i get whole dataset into map item, after that i throw lucky ...
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2answers
2k views

Batch merge large numbers of.asc grid files

I have >2.5k .asc grid files which I need to merge into a single overarching dataset. I would like to avoid having to convert them into esri grids first so was looking to use QGIS (v.2.0). I am ...
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2answers
107 views

Is it possible to alter raster values without Arcpy? [closed]

I'd like to be able to alter raster values, through fairly simple equations, without using the module Arcpy. Is that possible? It seems like gdal, numpy, and rasterlang might make this possible but I'...
3
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3answers
2k views

How to get count of non-NA raster cells within polygon using R

I've been running into all sorts of issues using ArcGIS ZonalStats and thought R could be a great way. Saying that I'm fairly new to R, but got a coding background. The situation is that I have ...
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1answer
435 views

QGIS 2.0 Howto copy raster data from a QgsRasterDataProvider to an OpenCV matrix

I'm hacking the half day arround a problem and that I' thought it was simple one. I'm using C++ (QtCreator) QGIS 2.0 und openCV2 on an 64 bit Workstation runnig Debian Wheezy. The Application I try to ...
2
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0answers
386 views

Intersecting vector data with raster data in PostGIS?

I have Open Street Map [OSM] data imported so that I can access the geometry of buildings. I have also loaded SRTM digital height data from NASA from a GeoTIFF raster. I have projected the raster into ...
2
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1answer
358 views

Analyse slope gradient from LiDAR .asc data

I'm new to using QGIS. I have purchased some LiDAR data which downloads as .asc format, is there a way to analyse the terrain slope angle from this data or does it need to be converted into DEM? ...
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3answers
303 views

How to create a multi-colored raster image based on long,latt,color information?

I want to create a multi-colored raster layer to overlay on my map in OpenLayers I have the following information in my DataBase: D_Cell_ID Long Lat ColorCode 055113 ...
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1answer
112 views

Cutting Raster using two Polygons as Masks

I am trying to cut this raster in order to drop the outside of the walls white area and the area with the dots. I made one step using as mask the green polygon but i couldn't remove the inside of the ...
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0answers
569 views

TIN to Raster Tool, output elevations are 3.40282e+038 and -3.40282e+038, tried calculate statistics didn't work

I have an input TIN file that I created using Create TIN. The elevations are all correct. When I convert the TIN to Raster using the tool, my output elevations are 3.40282e+038 and -3.40282e+038 I've ...
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0answers
138 views

Can I clip raster maps by vector boundaries on fly while serving them via geoserver?

I have a lot of georeferenced raster topographic map sheets which contain not only map itself, but some sketch elements like legends, stamps outside the map frame. I want to make seamless coverage ...
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60 views

Extract MultiValuesToPoints yields identical value for each band

I'm attempting to extract hyperspectral remote sensing data to a point featureclass using the ExtractMultiValuesToPoints ArcGIS tool. The value of each band (228 bands) should be appended as a field ...
6
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1answer
2k views

Raster vs Grid vs Lattice terminology?

I have a question about GIS terminology - what is the difference between grid and raster and grid and lattice - in theory?? I thought, that raster is regular network and value is in the cell and the ...
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1answer
161 views

Analyzing Raster Data From Vector Layer Buffer

I am using QGIS 2.0. I have satellite images of night-time lights all over earth. I also have a vector shapefile of country boundaries including the largest cities on earth. I want to use buffers to ...
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0answers
296 views

Choose what zoomlevel to read from for mbtiles file in GDAL

GDAL is supposed to read MBTiles files and to do so, it selects the highest zoomlevel available. However, is there a way to choose another zoomlevel? i.e. override the default and go for a lower one? ...
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1answer
146 views

How to read the count of the cells with data with non “no-data” values ,in QGis?

How to read the count of the cells with data with non "no-data" values ,in QGis
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1answer
96 views

QGIS Grid Division/Grid Product etc. results are wrong projection

I have several raster grids, all 4320 columns, 2160 rows in WGS 84 projection. They are loaded from ESRI ascii files. When I use the Processing Toolbox to carry out arithmetical transformations on the ...
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2answers
747 views

convert data.frame with no lat-long info to a raster

coders, I need to read in a .txt file into R and later do some spatial analyses on it. I’m working in R. 3.0.2 on a Windows server. I load the following libraries (probably more than I need): ...
2
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1answer
240 views

PostGIS Raster: Outputting raster into GDAL supported file?

I have import a raster into my postGIS database via raster2pgsql. My raster tiled to 100x100. Now I'm trying to export (output) the raster to GDAL supported file (for example: PNG). Following the ...
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2answers
352 views

Finding specific pixel values ​​in ArcGIS using Python

I have a raster file containing some integer values. I need to find all pixels whose values are not defined in list like this one: l = [1,2,4,8,16,32,64,128]. Is there any easy way to solve that ...
4
votes
1answer
1k views

How to calculate total number of data cells in raster?

I am using ArcGIS 9.3 and python 2.5. My code is shown at the bottom of this post. I have a raster containing fire intensity information at 200m cell resolution. I run the script and the first count ...
6
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1answer
1k views

Create a point at the highest value in a raster ArcGIS 10.1

I am trying to find the location of the highest value pixel in my Direct Solar Radiation Raster. I can see the extent of the data in my raster but don't know where the highest value pertains to. Is ...
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204 views

Importing GPS coordinates to extract multiple DN values in ERDAS

I have a set of GPS points (stored as a csv for now) and would like to import these points to ERDAS to find the DN values associated with each location. I am able to import a SHP to ERDAS but the ...
6
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1answer
2k views

How to extract pixel value counts from a raster in QGIS?

How does one go about obtaining a summary of the counts of cell values within a raster in QGIS? I know QGIS is doing this, in order to provide the summary statistics and histogram in the properties of ...
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1answer
360 views

Convert point to grid: Numbers of cells differ

In R I am trying to aggregate points data to a grid. The data for the grid (G-Econ) comes as a csv-file. In this file each row represent a grid-cell at 1x1 degree resolution and the given coordinates,...
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1answer
88 views

Should large Basemaps be stored in DBMS via ArcSDE?

As I understand it, the SDE Geodatabase provides the technology for Multiuser databases, Versioning, replication and other Geodatabase functionality. In my organisation, this could be useful for ...
1
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1answer
1k views

Convert polygons in shape file to a numpy array?

I have a shape file containing a number of polygons and all attributes being text. I'm trying to import the polygons into numpy as an array where each polygon is represented as unique values. I ...
4
votes
1answer
219 views

Simple way to compare ranges and distributions of species, looking for correlation and differences between ranges

As a biology student just beginning with GIS, wondered if someone could give me an idea of what tools to go about using to compare the range of 3 species that have trophic effects on one another. I ...
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0answers
150 views

How to split a raster into multiple rasters using QGIS?

I would like to know how to split a raster into multiple rasters in a single operation using QGIS. Although I can clip the raster image, it would be better to split it using a single operation. I am ...
2
votes
2answers
1k views

Can raster files from ArcGIS for Desktop be visualized in Google Maps?

I have raster files created using ArcGIS (Desktop application). On the other side I develop an application using google maps. Can I visualize those raster files somehow on google maps API?
0
votes
1answer
409 views

How do I use wildcards to work around the GDAL character limit?

I am attempting to use the 'Merge' & 'Create VRT' tools in QGIS 2.0 on a folder with 3000+ raster tiles in. However whenever I try to perform this operation the following error appears: 'The ...
3
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2answers
547 views

Using python to Raster clip the extent to be the same as the display?

I've been trying to figure this out for almost a week now. I am creating a tool which first needs the raster to be clipped out to the current display. I have tried all sorts of things. Below is the ...
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2answers
2k views

How can i convert a raster from continuous to discrete?

I have a tiff that is 'invalid' for a lot of tools and will not let me view the attribute table. I think this is because it is "continuous" rather than "discrete". Does anybody know how to convert it ...
2
votes
1answer
90 views

How to stop transfer of large raster into arcsde geodatabase

I have just realised that I will not have enough space on my harddrive to accomodate a raster which is being copied into an arcsde geodatadatabase. I am afraid, that if I stop the process in ...
2
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0answers
459 views

What are common mistakes when creating mosaic datasets?

I have a set of images taken from a unmanned air vehicle, they have lat/lngs when properties are clicked in windows, but when they are imported into ArcGIS they have no spatial reference or coordinate ...
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2answers
99 views

How can i combine the colours of one raster with values from another

I have two Tiffs with data from the same area. One is in colour and when I use the identify shows a 'color index' number (eg. 141), then Color(a,r,g,b)(eg. 255,90,255,0). The other tiff contains a ...
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3answers
605 views

Converting files for use in fragstats

To use my data in fragstats i need to convert it into a signed integer grid. I have the data in a raster format and have tried 'right click>data>export data> and setting the format to 'Grid' and it ...