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

learn more… | top users | synonyms

17
votes
3answers
819 views

Dealing with bridges and tunnels when modeling raster least cost paths?

I'm currently using ArcGIS 10 Spatial Analyst's Cost Path tool to model pedestrian routes. I have sidewalks, fences, buildings and a ton of pedestrian scale features, all combined into a cost surface ...
3
votes
2answers
390 views

Reading multiple grid data with Python and ModelBuilder

How can I read grid data (3 or 5 sources of grids) like slope, soil, cover, etc.? My goal is to build a simulator based on multiple grid data for harvesting decisions.
4
votes
2answers
3k views

Simplify Raster Contours ArcGIS 10

Does anybody know a way to simplify a number of contour polylines derived from a raster dataset? I need to generate a map that shows contour polylines at relatively small scale. With the contour ...
9
votes
2answers
560 views

How to add different sized rasters in GDAL so the result is only in the intersected region

I'm writing a Python method that adds two rasters and generates a single raster output. For reasons beyond my control, the extents of the input rasters are different, but they do overlap. Is it ...
1
vote
2answers
827 views

Tools/processes that avoid the need for raster to vector converstion?

A "brute force" method of solving GIS problems that involve acquiring values from raster cells and storing them on spatially overlapping vector features is to first convert the raster to a vector. The ...
3
votes
1answer
980 views

Workaround for Raster data input in ArcGIS Server Geoprocessing Service

UPDATE I have accomplished the Python script, but only tested in desktop environment, i.e. ArcMap. #Import ArcPy site package module import arcpy from arcpy import env from arcpy import Extent from ...
9
votes
4answers
8k views

How can I export raster data from Arcmap to an R *.grd file format?

I want to work with raster data in R, but I have problems exporting my raster dataset from ArcMap. By "export data"/GRID I get a file with an *.aux extension. What I need is *.grd. Can anybody help ...
4
votes
2answers
365 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. ...
1
vote
1answer
421 views

How to Create and Rotate Raster Dataset using ArcObjects?

I'm following the "How to create a raster dataset" tutorial: http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#//000100000464000000 The questions are: 1) How can I create ...
2
votes
1answer
337 views

Bounding box argument ignored when displaying raster using mapserver

I am trying to display a raster image with Mapserver using different bbox arguments in a mapserv cgi request. I have been trying to specify different bbox arguments to "crop" the raster display, but ...
6
votes
1answer
5k views

How to import a raster into PostGIS?

I'm trying to follow the instructions here to load a raster into a PostGIS database: python raster2pgsql.py -s 4269 -I -r *.tif -F myschema.demelevation -o elev.sql I understand that I replace * ...
9
votes
2answers
946 views

GeoTIFFs made in GDAL don't have min/max range when loaded in Arc/QGIS

I'm creating some floating point rasters in GDAL with the GeoTIFF driver. When I load the resulting images into QGIS or Arc the default symbology puts the min at -3.40282e38 and max to 3.40282e38, so ...
5
votes
2answers
175 views

Distortion of equally sized world tiles

My question is related to this: http://stackoverflow.com/questions/7927863/location-data-format-for-adehabitat-package I have a relational database with 'world tiles'. Each tile has a side length of ...
4
votes
1answer
1k views

Conditional reclassification of a raster

I am attempting to do a conditional reclassification of an NLCD land-use raster. I specifically want to reclassify all developed areas (classifications 22,23,24) that are near a road (classification ...
2
votes
1answer
644 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 ...
3
votes
1answer
378 views

Splitting raster pixels by a polygon's edge?

I have a a polygon shapefile of different regions, and a raster grid of precip data. I want to take the polygon and add up all the raster precip data in each zone. I could use zonal statistics to do ...
4
votes
4answers
3k views

How to use ECW images with MapInfo?

I'm wondering if there is a way to use ECW images in MapInfo without having to 'register' the image as I bring it in? I mean, ECW images are already rectified (well the ones I use for GIS are anyway) ...
10
votes
1answer
457 views

How do I randomly alter a raster map of habitat types?

I have a raster of habitat types for a specific area in Scotland. I need to create future habitat scenarios with changes in habitat to assess the population viability of a bird species. For example, ...
2
votes
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] ...
3
votes
1answer
229 views

How to calculate parameters for SQLServer raster to ESRI grid script?

My question is related to How to convert SQL Server Rasters to ASCII Grid? I would like to transform the data in the database into Esri grid format. I would like to write the program/script myself ...
1
vote
1answer
365 views

How to convert SQL Server Rasters to ASCII Grid?

I have 25km by 25km squares of the world in a relational database. Each square has coordinates for the top left and lower right corner as latitudes and longitudes. Each square also has an index ilat ...
9
votes
3answers
3k views

How to get hypsometric curve from elevation data?

I have my elevation data but cannot make an attribute table from it and so I'm not sure how to get any of that data into a table in order to make a hypsometric curve.
3
votes
1answer
891 views

Interpolate undulations for given points using a geoid model

I have two databases, the first one (F.tsj) contains gps points: coordinates and ellipsoid heights and the second one is simply a geoid model where every line stores latitude, longitude, and ...
3
votes
1answer
542 views

Georeferencing multiple rasters to World files

I've got exactly 56 tiffs to georeference. Each raster has its unique TFW world file. I'd like to automate this process. Each raster has it's unique name which is consistent with world file name (eg. ...
1
vote
2answers
2k views

How to set cell size for vector to raster conversion in QGIS GRASS plugin?

I'm converting a vector (loaded in GRASS plugin in QGIS (1.7.0.-wroclaw) and would like to convert this to a raster with a defined cell size. At the same time I need a value from the attribute tabel ...
4
votes
1answer
336 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.
3
votes
2answers
465 views

Need to clip raster based on field name in ArcGIS 9.3

Is there a way around for me to batch clip a raster using a field name to create output a raster layer ? Much like using Split tool but it is for a vector. How about that for the raster side ? Going ...
5
votes
3answers
556 views

Fastest way to test if raster contains data within a polygonal area

I am writing a python script for a geoprocessing tool in arcmap. I have a polygon in WGS 1984 Web Mercator (Auxiliary Sphere) and a raster grid, raster1, in WGS 1984. I reproject the polygon to ...
7
votes
1answer
195 views

Finding largest number of observations within a given radius

I have the following problem: Given the location of insured properties (say houses with fire insurance), i have to find the largest sum of insured values which fit into a 300m radius. Now, my first ...
4
votes
1answer
574 views

Can you use arcpy.RasterToNumPyArray() to Graph a Raster with matplotlib?

Can you use arcpy.RasterToNumPyArray() to Graph a Raster with matplotlib? I'm looking to graph a raster with X, Y, and Z values in a 3D bar graph. I just can't seem to translate the numpy array to ...
6
votes
1answer
215 views

What is the best raster format for large NoData areas?

Is there a good raster format for dealing with a large number of NoData cells? I do a lot of flood modeling and mapping, and recently I've been using rasters to show predicted flood depth and/or ...
3
votes
2answers
279 views

Hand fit curve and then apply to time series of rasters, make a map. How?

Maybe a data management problem, not too sure, but likely a challenge which someone has dealt with before. I have a time series of rasters. I can summarise the information by taking averages of each ...
3
votes
1answer
592 views

How does cost allocation work?

Why, when I use the cost allocation function of Spatial Analyst, is space not allocated in all input source locations (as shown in image below)? In particular, the input raster has 18 spots while the ...
3
votes
3answers
235 views

What FOSS GIS has the option to link attribute tables to rasters

In ArcGIS rasters can have attribute tables. What FOSS GIS offers a similar option?
14
votes
2answers
2k views

Good practice for generating contours from a DEM

We have just received a large set of DEMs at work and I would like to generate contours from them. The DEMs have a resolution of 1m and a size of 1kmx1km. Output from gdalinfo: Driver: ...
6
votes
2answers
2k views

Easily find centre point of a raster in ArcMap 10 document?

If I have, say, a rectangular and georeferenced raster file loaded in an ArcMap 10 document (.tiff w/ associated tfw), how do I easily find its centre point and store that point in a points vector ...
9
votes
1answer
474 views

How should I manage PostGIS Raster data with different projections?

I have a requirement to store and manage archaeological geophysics data that is collected as a rectangular array of samples -- a raster image. Each raster will usually 20x20 or 30x30 floating-point ...
1
vote
2answers
2k views

Merge single band and multi band color images

I do have 2 color images (orthophotomaps). One is only 1-band with color map and second is with 3-bands. How can I merge them with any FOSS tools or ArcGIS? Thanks a million
10
votes
2answers
2k views

PostGIS raster value of a lat/lon point

I have a tiff raster in my PostGIS 2.0 database. I want to get the value of the raster at a specified lat/lon point. I have: postgresql-9.1 postgis-2.0-svn with raster support a raster imported ...
5
votes
2answers
1k views

How to export a PostGIS raster to PNG?

I have a raster which is split into 30 tiles and I want to dump them all into PNGs. I've read the documentation http://postgis.net/docs/RT_ST_AsPNG.html but still don't know how to dump it well. If ...
8
votes
1answer
554 views

How to grid unevenly sampled categorical data?

I am looking for a method for gridding categorical data. I have extracted from nautical charts and field sheets a collection of points specifying the nature of the surface of the bottom of the ocean. ...
2
votes
1answer
507 views

Calculating beta-diversity w raster data [renamed]

Using ArcGIS 10, it is not possible to generate a raster attribute table for 32-bit float values. Instead, I have tried the RasterToNumPyArray method, which crashes since the file input raster is so ...
3
votes
2answers
816 views

What's a good way to display a custom raster basefile in Openlayers

I have a land cover raster that I'd like to display as part of an Openlayers based application. I'm able to load the raster directly as a PNG but my Openlayers application becomes VERY slow. I think ...
10
votes
4answers
1k views

Problems with NA values when reading .DEM file with R 'raster' package in Windows

I am trying to read a raster file in a .DEM format on windows using the 'raster' package in R. I get problems with NA values, when loading the data into R in Windows 7, but I do not have the problem ...
2
votes
0answers
315 views

Create custom pixel block size in ArcGIS 10?

I'm using the new IRawBlocks in ArcGIS 10 from the adopted sample in ArcGIS 10 SDK help and I want to create a custom sized pixel block that feeds me a block of values column by column instead of a ...
2
votes
1answer
755 views

DTED/GeoTiff layer: Get elevation under mouse pointer

I have a simple desktop app with a map control. The map data that will be available to show will be either DTED files (Military Analyst's catalog / MADTEDLayer), or GeoTiffs (created by gdal). I want ...
0
votes
4answers
3k views

How to Clip a Shapefile of Circle features using a Raster using ArcGIS 10

I want to keep all the features in the shapefile that lie in the raster region and reject others. How do i do this? ------Adding More Details-------- Data to be Clipped: Is A Shapefile of 1 mile ...
6
votes
2answers
1k views

FOSS method to split raster into smaller chunks

I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS ...
3
votes
1answer
972 views

How to handle time-based raster data in the ArcGIS Server JS API

The TimeSlider functionality in the ArcGIS Server JS API is great for working with time-based vector features - you can scroll forwards and backwards through time to see the vector features which ...
0
votes
1answer
346 views

Incorrect spatial extent for imported hdf image on ArcGIS

I imported an hdf image onto ArcGIS but I cannot make correct projection of it. Also, it does not have correct spatial extent (please see the enclosed figure, the small one is projected under WGS84). ...