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

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645 views

How to work with OS map files from Digimap?

I am trying to add map tiles as raster files in QGIS but when I add them they all appear on top of each other. I did this once before and everything was ok but I am now unable to find how to get the ...
4
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3answers
4k views

How to combine information from raster and vector layers?

in QGIS I have 1 raster-layer (elevation) and 1 vector-layer (administrative units). Now I would like to be able to query one of the administrative units and see the mean and min/max of the elevation ...
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1answer
463 views

raster in TOC to geotiff on disk in ArcPy

I am really hoping that someone out there who knows a bit about ArcPy in ArcGIS10 can help me out. I am attempting to automate some work w/ netcdf files. Basically, I am able to automate the creation ...
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2answers
593 views

Is it possible to generate a vector polygon from a polygon on a raster image?

I have a raster map which I have extracted from a government report providing flood extent return frequencies. I want to 'snatch' these flood extent polygons (i.e. convert to vector) and I was ...
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1answer
112 views

Global composite of radar data available?

Iowa State offers an exceptional NEXRAD composite image as GeoTIFF for the entire continental US at a reasonable resolution. Is there a comparable GeoTIFF composite updated semi-regularly available ...
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1answer
753 views

How to convert Geostatistical analyst (GA) file to Raster FAST?

I have been trying to convert a number of Geostatistical analyst files that i were created using Geostatistical wizard in ArcGIS 10. I want to save these files as Raster and use the File Am i ...
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1answer
274 views

Plotting Smith and Sandwell global seafloor topography grids

Does anybody have any experience with plotting Smith & Sandwell 2-minute Mercator-projected grids in ArcGIS? I've downloaded one in two formats: ers and img. I've found tools for processing .img ...
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1answer
2k views

How can I extract raster values around points?

I'm using ArcMap 10. I have a point dataset and a .flt raster. For each point I want the sum of the raster values that lie within a certain radius of each point. i.e. I want to extract values within a ...
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74 views

HOW to build a raster file from polygons showing subsoil layers classification?

I'm trying to build a raster map showing different subsoil features for a further analysis in ModFlow. I wonder how I can build a raster which shows different subsoil features?
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1answer
263 views

PostGIS Raster convolution filters

I've looked through the PostGIS raster documentation, but can't find an indication of how to apply a convolution filter to raster data. Does this capability even exist (yet?) There only appears to be ...
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2answers
3k views

How do I layer stack rasters in QGIS?

I have some multi-spectral data, where the individual bands are separate Raster files. How do I layer stack these rasters so that I get one raster with 3 bands instead of 3 different rasters? This ...
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6k views

How to clip a vector feature to the extent of an existing raster dataset using arcpy

I have a clipped raster dataset with polylines (from the contour tool) overlayed (see attached). I am trying to clip the polylines to the extent of the raster dataset, which seems simple enough, but ...
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2answers
779 views

Mosaicing LIDAR files in ArcGIS 10

I have a number of LIDAR files (the extension is .adf). When put together, they show the same area (each shows one part of it), so, before I do anything else with them, I would like to combine them ...
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1answer
204 views

Efficiently classify raster with irregular polygons

I have a project on my desk to classify an elevation model using different elevation breaks for each polygon in the area of interest. In pseudo code: FOR each polygon IN layer: CREATE_MASK FROM ...
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0answers
101 views

raster data expressed as percent

I downloaded NDVI greeness data from the USGS Integrated Vegetation Mapping Viewer. In the metadata it says that visual greenness values range from 0 to 100. My data is from the period ending 3/5/12 ...
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7answers
18k views

Get boundary of raster image as polygon in ArcGIS Desktop?

I have a rectangular raster image in ArcGIS. My question is: how can I produce a polygon which is just the extent of the raster image? That is, I want to have a polygon layer with a single ...
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0answers
232 views

Importing Rasters to ArcSDE 9.3.1 using sderaster

OK, I am trying to import a raster to 11g using the sderaster command. It is a stand alone jpg with a world file associated, and pyramids. Am I right in assuming I cannot import a JPG, I can only ...
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1answer
115 views

Can Identify tool to return the raw values of rasters?

I have a raster in ArcGIS 10 SP4 set to bilinear resampling in its display properties. When using the identify tool it returns the resampled value instead of the raw value. Can we get the identify ...
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1answer
461 views

OpenLayers ArcGIS Image Service Support

i have ArcGIS Image Server for publishing my raster data to my user. In traditionally way i have been tiling with gdal and it takes a long time besides this it requires more effort for getting true ...
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1answer
199 views

Progress bar percentage is increasing and decreasing, never finishing

I am trying to clip a raster by shapefile perimeter using the Clip tool. The percentage has been jumping between 0% and 100% for over an hour, back and forth, climbing to 100% then dropping down to ...
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7answers
3k views

how to overlay shapefile and raster?

I have a shapefile with polygons. And I have a global raster file. I want to overlay the shapefile's polygons onto the raster grid and calculate the mean raster value for each polygon. How can I do ...
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3answers
338 views

ArcGIS 10 Raster Mosaicing versus Lizardtech Express Server

Trying to determine if I still need to use Lizardtech Express Server to mosaic rasters together or just use the Mosaic Raster Dataset function of ArcGIS 10? I know for earlier releases of Express ...
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1answer
140 views

ESRI ISurface.GetElevation is extremely slow compared to GlobalMapper

I'm using ISurface.GetElevation on a Raster to get the elevation for a specific lat/lon. I have to do this for a huge set of datapoints. Currently i'm testing with a dataset of 10.000 items which ...
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1answer
233 views

How to change field name in raster file?

I´m having a bit of an understanding problem with a DEM TIF file. I have a DEM TIF file which is served with Geoserver. When I click on the layer the WMSGetFeatureInfo gives me the following output: ...
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3answers
1k views

How to combine corner-touching polygons into a single feature

I have created a polygon layer from rasters, and only have a single classification ID (and calculated acres) for each polygon. I would like to "dissolve" all touching features into larger, individual ...
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1answer
314 views

What is the easy way for extracting a dted raster file?

I have some SRTM data which was converted to dted file with GlobalMapper or ArcMap ascii to raster. I want to extract raster from vector with an easy way. I have tried "extract by mask" method but it ...
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1answer
3k views

Calculating distance to points in QGIS

Is there a way of calculating the distance to the nearest points in QGIS? In ArcGIS there is a function called Euclidean Distance, which can take an input vector or raster, and generate a raster of ...
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1answer
868 views

Conversion of raster features to polylines: skeletonization?

I would like to identify linear features, such as roads and rivers, on raster maps and convert them to a linear vector features (i.e. polylines). I typically use R as my primary GIS, and have posed ...
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2answers
3k views

Raster Combine - ESRI Spatial Analyst

I am trying to combine a whole bunch of rasters with Esri Spatial Analyst. Seems to be doing what I want EXCEPT the calculated output is only the area where all 4 rasters overlap. I am a complete ...
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2answers
947 views

GDAL Clipping (hack)

I am trying to use the python script from http://www.sparkgeo.com/labs/2010/07/07/gdal-clipping-hack/ to clip a raster based on many shapefiles. The script is using a mysql database an i would like to ...
9
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1answer
379 views

Efficient raster sampling of billions of polygons (bounding boxes)

How can a raster be computed efficiently (in Python), given a set consisting of billions of bounding boxes (read sequentially from a file), and given that the raster values for each cell should give ...
2
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1answer
205 views

Why is GRASS not thinning a terraflow raster properly?

I want to convert a raster map encoding directional flows (the output of r.terraflow) to a vector map. I'm using r.thin to process the output. It terminates successfully with 0 pixels removed during ...
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1answer
391 views

Looking for Mid-Holocene (~6000 BP) bioclim dataset

I am trying to obtain climate data for the Mid-Holocene (~6000 BP), preferably in the bioclim (19 bioclimatic variables) raster format. The worldclim.org website lists this dataset based on the CCSM ...
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1answer
2k views

Why is ArcGIS crashing when I try to load .adf raster data?

I am pretty new to GIS, so forgive me if this is a stupid question. I downloaded a bunch of land cover files from USGS seamless warehouse of Florida. Every time I try to 1) view the .adf file (which ...
3
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1answer
346 views

ArcSDE - How to edit mosaic dataset

I have a mosaic dataset (Raster) in an SDE database. As expected, when I click start editing, ArcMap says that I have to do "Register as Versioned" before, but I can't have a mosaic dataset in a ...
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1answer
667 views

Select vectors overlapping a raster

I have a raster layer with travel times from a specified point in my city's downtown. What I'd like to do is select all of the census blocks that lie at least partially within 45 minutes of downtown ...
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3answers
449 views

Adding .bil raster file to GeoServer and viewing it on GeoServer or GeoNode

Ok so my Boss gave me this job. Uptil now i was working on ESRI products and this is my first venture into OpenGEO. He has given me a link, http://www.worldclim.org/current, from where i need to use ...
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317 views

How to store Large Raster Images of Equipotential Surface Generation Using Monte Carlo Simulation?

I have a large (1GB+) raster that I am using as the base for the generation of an equipotential surface. This is to assess the accuracy of DEMs derived from another source. In situ observation is ...
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1answer
1k views

QGIS and satellite images band combination

When I add a satellite images as a raster in QGIS: 1. Why the image is changed, it looks like it has only one band?; 2. where is a tool for band combination? Thanks!
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6answers
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How to get X Y coordinates and cell value of each pixel in a raster using Python?

I’m really new to Python and I would like to know whether there is a quick method to get cell values of a raster pixel by pixel and the coordinates (map X Y coordinate of centre of each pixel) using ...
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0answers
815 views

ArcGIS 10 - disappearing rasters?

From time to time it happens to me that rasters disappear at certain zoom level in ArcMap, or only some parts of the raster (strips) show up. I'm working on WinXP, ArcGIS / ArcView 10, Sp2, rasters ...
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1answer
162 views

rgb2pct.py increases size of file 20 fold!

I wanted to reduce the number of bands of a tif file from 3 to 1... I used this command rgb2pct.py -n 256 fnp_braunschweig.tif fnp_bs.tif and it increased the size from 31mb to 778mb I actually ...
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2answers
3k views

Using individual bands from a multi-band image in ArcGIS 10 raster calculator

I'm trying to use individual bands from a multi-band TM image (IMG file) within the raster calculator in ArcGIS 10 (SP2/3). I can add individual bands to my MXD, but raster calculator will only use ...
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0answers
247 views

how to buffer a raster cell using Visual Basic ArcObjects in ArcMap [closed]

I am new in visual basic, I have a question about creating a buffer zone based on a raster layer. I have a raster layer named "Value_Raster", I have a textbox in the userform, I also create a tool ...
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1answer
755 views

1-band raster colour table workaround in QGIS

Does anyone know what the workarounds are for the 1-band raster colour table plugin in QGIS? Currently I find it will run once, then crash on the second iteration. The workaround I use is to delete ...
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0answers
191 views

How can I ignore NoData values in map algebra? [duplicate]

I need a way to exclude NoData from calculations. I don't want any NoData cells from any of the rasters to be used in pick or con statements.
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2answers
2k views

How to read this GRIB data [closed]

on this open FTP server (ftp://ftpdatos.aemet.es/modelos_numericos/hirlam005_peninsula/) you can find HIRLAM models from the Spanish meteorological service. The documentation in the LEEME files (in ...
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3answers
2k views

Poor image quality of raster pyramid files in ArcGIS Desktop (no anti-aliasing)?

There are several GeoTIFF files (size ~7000x7000 px) which I try to open in ArcGIS Desktop 10.0. I have already created raster pyramids for them (.ovr files) using geoprocessing tool but their quality ...
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2answers
1k views

How to animate raster time series using open-source GIS?

I have a bunch of rasters taken about 10 minutes apart, and I have a nice QGIS project that produces pretty enough maps of them. I'm wondering if there's a way to animate this raster series, with a ...
5
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2answers
2k views

Using SearchCursor to access & export values in a raster table

I am desperately trying to export the values in a raster table to a .txt file. I've seen some other folk post about this, but for some reason can't get the code to work in my case. I have a raster, ...