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

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810 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
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5answers
747 views

Python loop Polygon to raster not working

I want to convert a large number of different shp polygons to raster in ArcGIS 10.1, using an existing field column "class" for the new raster classes. I am not very fluent in python but I thought ...
4
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1answer
855 views

Raster data on PostGIS

I need to publish raster and vector data through GeoServer WMS service and I have already chosen PostGIS as datasource to keep vector data. Now I would like to know what is the best practice to work ...
4
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1answer
1k views

Multiple Conditional Reclassification - ArcGIS

This is a question out of curiosity rather than a problem as I am not the most experienced with raster datasets and I wonder if there is a better solution to my current approach. I am trying create a ...
4
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2answers
469 views

How to fix a raster with wrong Eastings?

I get an error when trying to warp a tif file in QGIS: ERROR 1: Too many points (35721 out of 35721) failed to transform, unable to compute output bounds. I am using QGIS 1.7.0 Wroclaw with gdal ...
4
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1answer
226 views

How to sort entries in raster legend?

How do I reorder the Value field in a raster? There is no up or down button in it.
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2answers
450 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. ...
4
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1answer
834 views

Can QGIS resample Rasters during display?

When I was using ArcGIS a user could resample a raster during the display (I think via layer properties under the display tab). This would smooth the appearance of the raster so it wouldn't appear ...
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5answers
3k views

Problems merging DEMs or other raster datasets? Clipping Raster dataset to vector line?

I have two DEMs that I am going create a hillshade from, and ultimately want one hillshade clipped to a county boundary. I am running into a couple problems, though. When I try to merge the two ...
3
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1answer
138 views

Getting Zonal Statistics of Overlapping Circles?

I have a Buildings (polygon) shp file and a DSM. what I wanted to do was to get the pixel values for all the vertices of those buildings, and find another pixel value just around those vertices (say ...
3
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2answers
225 views

The fastest way of generating tiles from raster?

I have some MODIS imagery 250m resolution covering a large area which I generate tiles from using Mapnik and generate_tiles.py script. I need to run this script every day with new satellite images, ...
3
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2answers
178 views

Calculating Z-scores in Arc

I am trying to take the natural log and then calculate z-scores on cell values in several composite band GRID rasters in Arc. I am not fluent in python and do not see a way to automate this within Arc ...
3
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2answers
162 views

How to do regression analysis out-of-memory on a set of large rasters in R?

I am trying to do a regression analysis on a set of large rasters (254,004,000 cells each). Ultimately, I want to run something like the following (or a bit more complex, but let's start simple!): ...
3
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2answers
609 views

Majority filter (minimum mapping unit) in ArcGIS with larger window size

I want to run the majority filter in ArcGIS with a window size of 4 or 5 i.e. greater than the default 3. Is it possible? Or some other command (or tool) which might help me achieve that? thanks!
3
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1answer
1k views

How to convert jpg file to shapefile? [duplicate]

I am developing a GIS application like this: By now my steps are: I have got a jpg file, 5040 x 8179 dimension. In this map, the roads, rivers, towns etc. are marked. I am using .Net to develop ...
3
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1answer
210 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 ...
3
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1answer
283 views

An error in raster calculator in Arcgis

I wrote and ran this formula in raster calculator in ARCGIS. But the following error gets me into trouble. Does anyone have a suggestion to overcome this? Here is the formula I wrote and the error ...
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1answer
379 views

How to reproject a raster to Winkel Tripel projection?

I'm trying to project a raster map (in ASCII grid format) from longlat to the Winkel Tripel projection. But I'm running into errors, for instance gdalwarp won't accept the proj-string. $ gdalwarp ...
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1answer
1k views

ArcGIS 10 trouble displaying raster correctly

I think I've come across a Bug in ArcMap 10 in displaying rasters. This particular model comes from the USGS GAP Species dataset with metadata hosted here. I'd like to know if anyone else has ...
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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: ...
3
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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 ...
2
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1answer
62 views

Georeferencing a raster using GDAL and Python

I want to georeference a raster using python and GDAL. My current approach is to call gdal_translate and gdalwarp using os.system and an ugly list of ground control points. I'd really like a way to do ...
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1answer
87 views

Dealing with raster: creating it in projected CRS and exporting it in geographic CRS

When creating a raster from a polygon (the CRS of the polygon is a geographic coordinate system), the raster is created in the projected coordinate reference system of the data frame, which is a ...
2
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2answers
113 views

QGIS Raster Calculator: Need values to be set to 0 instead of no data

I have a landcover map with different values for the landuse options e.g. 190 for commercially used areas. Now I want to extract only these areas using the Raster Calculator with the expression ...
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3answers
80 views

Zonal Statistics as Table Tool

I have a slope dataset. I have a polygon shapefile with territory within the extent of the slope map. I have to calculate the real surface area of this shapefile using the zonal statistics as table ...
2
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2answers
110 views

Gdal: highest and lowest point/pixel, how to get their altitudes?

Given a .tiff topographic raster image. How to get the altitudes of the highest and lowest point/pixel ?
2
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1answer
81 views

How to translate (reposition) a .tif raster layer?

I'm starting to use QGIS for my thesis (environmental physics) and have to admit I'm pretty ignorant about it - I've always used Mathematica or Matlab. My problem is: I have a raster layer, in .tif ...
2
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1answer
159 views

Efficiently check for equal adjacent values in raster calculator

I have a raster consisting of integer values in each cell. I want to check every adjacent cell in a 3x3 grid to see if any one of the adjacent cells has a value EQUAL to the center cell, and if so, ...
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0answers
542 views

Projecting a Raster from WGS84 to planar Equal Area to Calculate Area: How to Select the Cell Size?

I have a broad question on how to calculate the 'correct' cell size for a raster when analyzing an area not at the equator. My goal is to project a land cover raster provided in GCS WGS84 to an equal ...
2
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1answer
514 views

Create raster distance around a single point feature class

Okay, so I'm relatively new to ArcMap and I'm trying to use the Fuzzy membership for suitability test. I have a single point feature class that I want to use for this analysis. I know that in order to ...
2
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2answers
326 views

Can Geoserver return the raster value of a lat/lon point

I have a GeoTIFF published by Geoserver 2.2 and being used by Leaflet via WMS. How can I get Geoserver to return the raster value at a lat/long point? I'm guessing it has to do with using WCS, but ...
2
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3answers
454 views

Raster dataset doesn't exist error

Dataset exist and I am able to get statistics from ArcGIS python window. But it failed as a script with error: ERROR 000865: Input raster: C:\temp\ras does not exist. I have tried following ...
2
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0answers
514 views

why preview image is blank for ImageMosaicJDBC (postgis raster) layer?

I follow http://docs.geotools.org/latest/userguide/library/coverage/pgraster.html to publish a ImageMosaicJDBC layer in geoserver. the layer seems published ok and saved, but the preview of this layer ...
2
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1answer
395 views

Querying PostGIS Raster with MultiPoint

For one of my projects using PostGIS 2 I have a table with GPS tracks (igc_files). It holds records including a MULTIPOINT() column that has about 1,000 points for each record and a column that has an ...
2
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1answer
432 views

accessing postgis raster data using Query layer in ArcGIS

I tried to load raster file (jpg) into post gis using the syntax provided here "C:\Program Files (x86)\PostgreSQL\9.1\bin>raster2pgsql -I -C -e -Y -F -s 102003 -t 300x300 ras_test.tif ras_test1 | psql ...
2
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1answer
403 views

Recreating A Lat/Long Grid Using a Specified Formula

I'm trying to recreate the Gridded Mercury emissions 2000 (0.5 x 0.5 degree grid) designed by the Arctic Monitoring and Assessment Programme. The file is in ASCII format, but without any coordinates. ...
2
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3answers
1k views

Batch script converting and resampling orthophotos

I would like to convert more than 300 orthophotos produced at scale 1:8.000 with a pixel size of 0.8m X 0.8m from Ecw format to Tiff format and after resampling pixel values. My aim is to batch ...
2
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2answers
2k views

How to exclude missing values from raster layer?

In my raster layers the value -999 means "missing". Those points completely mess up any colormap in qgis because qgis treats them as normal values and includes them in the classification. I would ...
2
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1answer
471 views

SUM Area irregular polygons per grid cell

I have a shapefile of irregular polygons and a GRID (both as raster and polygon grid). How can I count the AREA SUM of irregular polygons per grid cell? Can use ArcGIS, QGIS or R. (Application: ...
2
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1answer
301 views

Reproject TM65 to OSGB in ArcGIS

I have a TIFF file in the TM65 (Transverse Mercator) projection, and want to convert it to the OSGB (British National Grid) projection. I'm trying to do this in ArcGIS using the Project Raster tool. ...
2
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1answer
523 views

Simple band arithmetic on GDAL virtual rasters (VRT)

I want to calculate the difference of two bands. I have the individual bands stored somewhere, but I was thinking that maybe there's a way of producing a VRT file that is the result of this ...
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2answers
2k views

Converting ASCII grid/NTF to SRTM/DEM

I want to use the Ordnance Survey Land-Form Panorama product in some software called Maperitive, which can read custom SRTM DEM files. The data is provided in the following formats: DXF [Contours] ...
2
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1answer
411 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 ...
2
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1answer
303 views

Two rasters created from the same polygon have different extents?

My problem is that i am trying to export some rasters to Rockworks so that i can create a sand layer from them. Rockworks requires the grid files i use to have the exact same XY co-ordinates. So i ...
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2answers
1k views

Converting google map api coordinates into meters

How would I go about converting the results of my map bounding box into meters within javascript? For example, if I have the coordinates 51.52366625446907, -0.07467269897460938 decimal degrees, can I ...
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1answer
3k views

How can I compute raster pixel width and height given raster bounds, row count, and column count?

Restated, how do I convert arc degrees to meters? For example, I have an elevation data raster that has the following metadata: WEST LONGITUDE=64.97798789° E NORTH LATITUDE=33.02003415° N EAST ...
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1answer
35 views

Loading raster in postgis and link it with an existing table

Relatively new to PostGIS and I am currently exploring the options to make one of my PostgreSQL Tables spatial. Essentially I want to store a raster object in a table that also contains essential ...
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1answer
47 views

Export Multiple Raster Data with custom Cell Size

I Have 172 Raster, and need to change the cellsize. So I use Export Data from TOC and change the cellsize manually (example I want to change it to "3") I tried using this python script to ...
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1answer
52 views

Error on 'Extract raster values (CSV)' - Error executing algorithm 1 'Dataset' object has no attribute 'mapToPixel' See log for more details

I would like to extract raster values at some locations (point shapefile) in 'csv' format. I use 'Point Sampling Tool' and it works well for a raster file. However, I have hundred of raster files ...
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1answer
181 views

QGIS GRASS Missing Dependancy

I want to perform a view shed analysis in QGIS using GRASS 7 r.viewshed. When I double click on r.viewshed in GRASS GIS 7 commands in the processing toolbox of QGIS I get the following message: ...