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

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15
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908 views

Speed of various raster data formats

I'm having trouble locating any discussion or comparative benchmarking of different raster file formats (e.g., for use in data analysis in R). Does anybody have any insight into why particular formats ...
6
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2answers
3k views

How to extract road and building features from raster data?

I work with raster data and my task is to digitize a big image. This consumes much time just for digitizing roads and buildings! I'm looking for tools to simplify working on raster data to digitize ...
2
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1answer
2k views

Issue with Mosaic to New Raster tool

I am having a major issue with the Mosaic to New Raster tool when importing ASC files. It processes the first few files but not all of them. I thought it was a space issue and tried to split the input ...
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0answers
142 views

How to retrieve the value of a cell in RasterLite?

Just wanting to know the SQL statement needed to find out the pixel value for a location, when the raster is loaded into SpatialLite as a Raster? I loaded the Raster using rasterlite_load -d ...
1
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2answers
196 views

Finding zones with nodata in ArcGIS 9.3

I have a DEM raster with some small and large areas of NoData. I also have a raster defining zones (the zones consists of a rectangular grid). I want to create a new raster marking the zones where ...
2
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1answer
130 views

How to Separate out the disconnected regions of a raster into independent rasters using ArcGIS?

Please refer to the attached image. The overlay on the map shows a raster file with disconnected circles. I want to split each of those circles into independent rasters in one shot. Is that even ...
2
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1answer
1k views

Adding fields to raster attribute table

I have a raster attribute table associated with an IMAGINE .img raster that I build and open with: IGPUtilities utils = new GPUtilities(); IRasterDatasetEdit2 raster = (IRasterDatasetEdit2) ...
4
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2answers
1k views

How to find the area of raster values within polygon zones?

I'm using ArcGIS 9.3 and I just can't seem to get this right - I've tried tabulate areas, zonal stats, converting to polygons, etc. I'm missing something somewhere. I have a USGS impervious surface ...
6
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1answer
356 views

Normalizing and adding kernel density rasters

I have 4 years of road kill data for one road, though each year has a different sample time frame (i.e. May-June vs. April-October) and therefore each year has a different number of surveys and totals ...
6
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3answers
1k views

How to find the elevation differences between adjacent pixels in ArcGIS?

Is there a way to determine what the difference in elevation is between two adjacent pixels? I am using an SRTM DEM to map faults. I am using the vertical error (>16m) as a criterion for the ...
11
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5answers
2k views

How to scan large paper maps without a large format scanner?

Is there a way people have used to import a paper map as a raster without using a large format scanner. I do not want to cut my map. I'm wondering how much success people have gotten using things like ...
1
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1answer
225 views

How can GRASS export an .flt file?

I am using GRASS and connecting it to another application. The other application needs an FLT file of the raster map which I should export from GRASS. The other application only reads FLT files. Can ...
15
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4answers
2k views

Where can I find examples of fuzzy logic applications in ArcGIS?

The last ArcGIS version (10) includes two arctoolbox tools for fuzzy logic (Fuzzy Membership, and Fuzzy Overlay). Does anyone know where can I find some examples showing how they can be applied? ...
5
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1answer
900 views

How to display dynamic raster (lidar) data on a Web map?

I have some high quality LiDAR data. I need to process it dynamically, and update a field (not elevation field) depending on my input and elevation at that point. Once this is done, I need to display ...
1
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2answers
382 views

How to translate (reposition) a raster in Python?

I tried to use QGIS GeoReferencer to translate a raster layer, but somehow failed. It just goes to somewhere unexpected. Now I decide to do it myself, with python. I think some libraries like GDAL ...
4
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2answers
244 views

Finding Raster Overlap within a Directory

Here is the scenario: I have a directory with 100+ map projected, single band, rasters that weighs in a 40GB+. I have used ArcMap's built-in mosaicing tools to create a raster mosaic. I am using a ...
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0answers
138 views

How to get SplineWithBarriers to work in C#

I have been having fits trying to get SplineWithBarriers to work but to no avail. My environment: Windows 7 64 bit Visual Studio 2010 Team Edition ArcMap Release Version 10.0 Product Version: ...
8
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3answers
4k views

How to find the locations of the highest values in a raster?

Using ArcGIS 10, I have a raster where I would like to find the pixel with the maximum value in the raster and return its location (center of pixel) in decimal degrees. I would like to iterate through ...
4
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2answers
425 views

What generation of the MrSID format is supported by ArcGIS 9.3?

This is probably old news to some, but I just learned that MrSID (.sid) files have different 'generations' of file formats - so there are MrSID Generation 2, Generation 3, and Generation 4 files. ...
5
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1answer
314 views

How to label raster cells in QGIS?

I try to show a small resolution raster file in the QGIS Print Manager tool. I would like to show a small label with each cell value (position - circa middle of each cell). How I can do it? Is there ...
4
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1answer
1k views

Filtering a raster by pixel cluster size in ArcGIS?

I have a raster image representing islands in a river (see image) created using the following process: 1) Clip a water surface DEM and watershed DEM by a bounding polygon (waters' edge). 2) Subtract ...
2
votes
1answer
200 views

Get Cell Value Webservice for ArcGIS Raster (LiDAR) without using ArcGIS

I want to expose the getCellValue function on Lidar Data, as a web service. But I don't have access to ArcGIS (server or desktop). What options do I have to fetch cell value, given lat lon, from a ...
3
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2answers
762 views

How do I only view selected rasters from a geodatabase raster catalog in ArcGIS 10.0

I am using a geodatabase raster catalog to hold raster files for multiple countries, mostly for the sake of organization. I don't actually have the need (often) to visualize or draw these all at once. ...
8
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2answers
723 views

How to convert a vector boundary to a raster map?

I need to output a PNG file of a raster map overlayed with boundaries present in a vector map. The problem is, the r.out.png script only exports a raster map. My boundaries are in a vector format. ...
8
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3answers
744 views

Best way to manage large number of geoTiff rasters

I have around 2-3000 1-bit geoTiffs of size 11000x9400. Color 0 should be transparent, and QGis gets it wrong in the first place, so I used a .vrt file to set all the parameters in one single place. ...
3
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5answers
2k views

arcpy : Add Raster Layer layer without lyr file

i wonder how i can add a raster layer to a remote (not the current) mxd file with arcpy. I need to not use a lyr file for that. For vector Layer i have the following lines working fine : mxdPath = ...
5
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4answers
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How to generate a world file with rotation

I`m writing code to geo reference some images that I get with a rc plane. I have the central coordinate of the image because its atached to the center of the plane. But I have problems when I open the ...
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2answers
2k views

Get extent of Georeferenced Rasters in Python and output to polygon shapefile

I would like to create a shape file containing the extents of each of the rasters in a directory. Is it possible to capture the extent of a raster using Python? I have tried ...
0
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1answer
190 views

Where to get raster files of Earth, united states [duplicate]

Possible Duplicate: Open access repository of general GIS spatial data? I'm brand new to GIS programming so please excuse my lack of knowledge. I am developing a GIS web app using ...
5
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3answers
3k views

Insert Raster to MXD using arcpy.mapping (ArcGIS 10)

What i want to do seems simple. But again i can't even find a workaround... I have got a lot of Raster-files (ESRI-GRID) which i need to insert into a layout mxd-file and then export the map to ...
1
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0answers
192 views

vba code for algorithm to assign track file gps UTM coordinates (East Africa) to an overlay 5x5km grid cell

The GPS coordinates are temporarily imported in to an Access database from DNR Garmin files downloaded (as dbf file(s)), and then exported for mapping in AEJEE (ArcExplorer Education Edition). I need ...
6
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2answers
2k views

QGIS and Raster Mapping in 'Seamless' layer

I would like to use Ordnance Survey base mapping in QGIS. I would like to set up something like a seamless table in MapInfo. I think that the equivalent in QGIS is a Virtual Raster Table. The files ...
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0answers
231 views

Assign Custom Band Combination To Image Catalogs In ArcGIS

I have an image catalog composed of 4 band rasters. I would like to use the same image catalog, and set custom renderers for a true color and false color combination and save each of those catalogs ...
1
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2answers
542 views

How to import .flt files into GRASS?

I am trying to import a raster file (.flt) into GRASS. The raster file (.flt) was generated from HEC-RAS. The said raster format cannot be imported into GRASS (it shows the error "file not ...
3
votes
1answer
3k views

Why can't I get MapServer to show a raster?

I am trying to use MapServer to display a raster image (png). That's it for now at least. However, I am having no luck. When I visit my map by using a link like: ...
6
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1answer
876 views

ArcGIS 10: Adjust custom grid intervals based on map scale?

I am preparing a pmf which includes a custom grid overlay. To clarify: a custom grid overlay is marginalia, not a feature class with geometry (so a scale dependecy inside a layer won't work). The ...
2
votes
4answers
7k views

Avoiding Raster to Shapefile (Polygon) errors 000863 and 000308?

Have you experienced converting a polygon from raster? The raster dataset is a satellite image created from zonal statistics? The problem is when I was converting the raster to polygon errors came out ...
4
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3answers
510 views

How can I have ArcGIS not automatically add raster clip output from Python window to the current map

I have a collection of rasters that I'm writing code to automate clipping based on a user defined shapefile. I am currently doing this in the Python window using the following as the main processing ...
0
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1answer
347 views

NDVI image value

In order to get monthly NDVI image with max value from two 16 day-images, I used mosaick tool in ERDAS8.7 by choosing max function from "set overlap function" tool. But after doing this, when I see ...
2
votes
1answer
414 views

Why won't this simple raster layer in my mapfile show up?

I am trying to get a simple raster layer to work on MapServer. I am not exactly going to be using geographic data, but I want to "georeference" multiple rasters together to create a map-like ...
3
votes
5answers
1k views

When a raster is clipped to a polygon with Python, why does it still take on the extent of the entire shapefile?

I am clipping a raster image to each polygon row in a shapefile in ArcMap 9.3 using the Clip tool (Data Management) in Python with Clipping Geometry set. While the clipped raster successfully depicts ...
4
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3answers
1k views

How to clip raster image by the extent of each row in a shapefile with ArcGIS 9.3

I'm using Python to clip a raster image by each row in a shapefile with ArcGIS 9.3. I am hoping to end up with one raster image for each polygon row, clipped to the extent of the polygon row. ...
12
votes
4answers
472 views

When should I be calling a 'rectangular grid of pixels' a raster or an image?

Reading through GIS literature, it sometimes feels that authors use the two terms with a specific meaning in mind. I always treat the terms interchangeably. Am I wrong? Read the first line in the ...
3
votes
2answers
701 views

Overlaying GPX data on rasters in QGIS

I have a series of raster map images that I would like to use in QGIS and overlay some simple GPX routes over the top to produce a custom map image. This is all quite new to me so please bare with ...
19
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3answers
4k views

What is Lanczos resampling useful for in a spatial context?

GDAL includes a resampling method beyond the normal mix of nearest neighbor, bilinear, cubic and splines: "Lanczos windowed sinc resampling". I understand that its a convolution filter, but unlike ...
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1answer
126 views

Clip GAPAnalysis and save as a new file output strange looking colors

I download USGS GAP Analysis and use a polygon to clip raster from that GAP Analysis. I am wondering why there is a strange looking color when you clipped the raster. If you zoom in, you can see ...
5
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2answers
596 views

BBOX and Projections of WMS services in Geoserver

we have tried to overlay a raster layer on Google map and have some difficulties to align the raster images onto the base map. When it is on the overview (Zoom level 1), it looks like this: On a ...
2
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4answers
470 views

Extraction of monthly image from two-16 day images

I need to conbine two-16 day NDVI image into monthly NDVI image. To do this, what kind of function and formula are used in ENVI, ARCGIS or ERDAS? Best regards,
5
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3answers
2k views

resize image resolution from 1000 m to 250 m

I'm beginner of ARCGIS and RS. I have many problems with the procedure. One of them is I have NDVI images and Soil map. Both are at the different resolution: NDVI is 250 m. soil map is 1000 m. So I ...
2
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1answer
396 views

How can you make RasterToASCII_conversion observe environment setting output cell size?

I have two rasters (an ESRI grid and an IMAGINE image) that differ in projection, extent and cell size. I want to convert the IMAGINE to an ASCII, and want it to have the extent, cell size and ...