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

learn more… | top users | synonyms

1
vote
0answers
734 views

How To calculate raster land cover inside overlapping buffer zones?

I am working with a raster land cover file that consists of several land cover types (e.g. forest, buildings, grass ect.) in total there is 40 different land cover types. I have 1200 bufferzonen ...
2
votes
3answers
270 views

How to create a raster from scratch

I realize this isn't a geographic question as I'm not trying to make this into a geographically placed image. But I hope you all will know how to do this. I want to make a raster from scratch. I ...
0
votes
1answer
61 views

USGS FLT Hdr file interpretation

I have a legacy program that attempts to read USGS 1/3 arcsec data. When I compare results to GDAL, I find that the lat/lon to pixel conversion is off by 1 line. The reason (I think) is because the ...
2
votes
1answer
192 views

Reproject gif.gz raster to WGS84 in QGIS

I am a steep learning curve into QGIS. I have a raster of global fire maps from the modis site: http://lance-modis.eosdis.nasa.gov/imagery/firemaps/firemap.2013221-2013230.8192x4096.gif.gz I would ...
4
votes
2answers
1k views

gdal_calc.py outputs huge files

I think this is a general enough question to apply to more than just gdal_calc, but perhaps not. When I run gdal_calc.py -A map.tif --outfile=deforestation_00-10.tif --NoDataValue=0 --calc="A >= ...
2
votes
1answer
424 views

Can I update the service on ArcGIS for Server programmatically?

There is Windows Service. This service adds user raster data to the Raster Dataset in sde database. The Raster Dataset registred on the ArcGis Server. This Raster Dataset also was publishing on ...
1
vote
2answers
630 views

How to georeference a raster based on identical, already georeferenced raster

I have two identical rasters, one has been georeferenced, the other has not. I would like to georeference the second raster automatically using the first one. I do not want to create links by hand and ...
1
vote
1answer
676 views

identify percentage of raster cells within a polygon

As per the title I want to determine the population inside multiple polygons according to different land use zoning (High Residential, Low Residential, National Parks etc) that's in raster format. ...
0
votes
1answer
264 views

How to delete raster dataset from sde base programmatically

I use sde database, registered with ArcGis Server 10.1. Sde connection is direct. Database container is postgres. There is a raster dataset in this sde base. I can open this sde database ...
0
votes
1answer
164 views

Rotating raster grids using ArcObjects changes cell size in ArcGIS Desktop?

I am using ArcObjects, namely RasterGeometryProc, to apply rotation on grids. The transformation works fine. However, when looking at the grids properties in ArcGis, the cell sizes has changed. ...
2
votes
1answer
239 views

Change Values of Georeferenced Raster

I am using QGIS to georeference B&W images. I have now done this and would like to set the black surround of the image (as a result of the georeferencing) to transparent but this does not work as ...
0
votes
1answer
877 views

Polygonize.py: AttributeError: 'NoneType' object has no attribute 'CreateDataSource'

Given a topographic raster tif of an european country where elevations are simplyfied to either 0, either 200. How to create a polygon ? Comment: With the following polygonize.py command: ...
4
votes
3answers
2k views

Is there a Raster Equivalent of the Split tool?

I have the DEM of a State in ERDAS Imagine (.img) format. I have a shapefile containing the counties of that state. I want to split the whole raster into DEMs of the individual counties. The counties ...
0
votes
1answer
2k views

How to conditionnally assign a new value to pixels of a raster image?

Given a topographic GIS raster of one country crop.tif: Given a know pixel value such as elevation (z) is +73 : $ gdallocationinfo crop.tif 1 1 -valonly > 73 Given an elevation threshold n = 50 ...
1
vote
2answers
614 views

Gdal: How iterate through all pixels of a raster image?

Given a topographic raster image. How to iterate through all pixels of this raster image ? Solution preferably with gdal, in console. Some other libraries/script could be installed. Related: ...
2
votes
1answer
891 views

How to work with flt & hdr files

I have been working on a vector-based spatial analysis in R using shapefiles. I wish to use some environmental data that is downloadable, however it is only available in raster format (FLT & HDR ...
1
vote
1answer
837 views

Gdal: How to get a pixel's value from raster image?

Given a topographic raster image. Given a pixel's coordinate in pixel/lines or geocoordinate. How to get it's pixel value ?
2
votes
1answer
146 views

Revert back from RGBA raster to original 1 band raster cell value

I have a number or single band raster grids that have been converted to RGBA (png). I no longer have access to the orignal single band raster data but have the png files. Is there a way to convert the ...
0
votes
0answers
98 views

Vector/Raster Intersection - Speedup and replacement for ST_Centroid

I have some raster data which is the altitude above sea level and also some vector data which represents building outlines. What I want to do is grab some buildings outlines and fetch all the raster ...
2
votes
0answers
331 views

How to render a transparent raster layer on top of one or more vector layers with PyQgis?

I been trying to render a map with a 3 vector layers and one raster layer. The idea is that the raster layer should be on top of the other 3 vector layers. The problem is that even when I add the ...
0
votes
1answer
564 views

How to change rasterlayer color?

I have rasterdataset in gdb. I create layer from this rasterdataset. private static void CreateLayer() { ... IRasterLayer rlMosaicDataset = new RasterLayer(); ...
8
votes
2answers
2k views

How to calculate the number of cells with a given value?

I have a raster file where all cells have values between -3 and 7, no data value is -9999. Have can I calculate the number of cells with a specific value e.g. 6? Can I use the calculator?
3
votes
1answer
7k views

Import PDF to qgis

i have a PDF containing a region of Baltimore city that contains lots of polygons in it. you can download it from here: ...
1
vote
1answer
29 views

Searching 'select by color' for raster or map data

I'm planing to create an online map component with which the user can create/draw polygons based on underlying raster data. Is there some library / tool / procedure existing which enables the ...
5
votes
1answer
1k views

QGis Save Raster as Rendered Image

In QGIS 1.9.0 Master, when you right click on a raster in the Layers Panel and select "Save As", you can select the output mode to be "Raw Data" or "Renedered Image". When selecting the Rendered ...
4
votes
1answer
1k views

How is slope of a surface in an arbitrary direction produced?

I am currently developing a program that requires that I calculate the slope for each cell in a DEM. However when I try to understand the algorithm to be used I get stuck trying to understand exactly ...
3
votes
1answer
599 views

How to calculate the distance to multiple locations from each cell of my raster?

I'm working with Arcgis 10.1 and Python 2.7.2 How can I calculate the distance to multiple locations from each cell of my raster? I tried euclidean distance but it only provides the distance to ...
1
vote
0answers
185 views

QGIS merge rasters error

I've been trying to merge some raster tiles at work and I've been getting an error message saying I don't have the correct permissions. This works fine on my home pc. Any obvious reasons for this? ...
0
votes
1answer
100 views

Precipitation or snow cover raster data for Scandinavia

I am looking for free precipitation or snow cover data in Scandinavia mountain during the winter 2011-2012. The WorldClim dataset is not enough acute. I would like 500 m scale at least. There is ...
2
votes
2answers
338 views

Convert ASCII Grid Colorized to Raster

I have an ASCII Grid file + .prj file and can visualize this in qGIS. I can colorize it by going to properties and using a Pseudocolor Ramp. However, I want to export this now as a TIFF / Raster. ...
0
votes
1answer
128 views

Integer rasters referring to the same scale

I'm using ArcMap 10. I want to display the area of simulated avalanches. I want this area to be divided in different colors depending on the thickness of the deposit. I managed to do that. But I want ...
1
vote
0answers
137 views

convert vector with multiple attributes to multiple rasters

I have a vector polygon feature with multiple attributes/fields. Ultimately, I want to convert it to a raster 'stack,' whereby each of the attributes/fields will be a different band of the raster ...
2
votes
1answer
186 views

Retrieving proportion of pixels in R

I'm trying to retrieve the following pixel statistics: Proportion of zero value pixels: [nº of zero value pixels / (total nº of pixels - nº of NA pixels)] Proportion of pixels smaller than 3rd ...
0
votes
1answer
133 views

Multiple Rasters into PostGIS

This may have been asked before, but A) what software/libraries etc do I need to B) load multiple rasters into PostGIS? I have Python 2.7.5, QGIS 1.9 (latest Weekly Build), PostGIS (whatever the ...
1
vote
1answer
244 views

Can't view PostGIS rasters after changing schemas

I have loaded a few rasters into the Public schema of a PostGIS 2.0 database. Using the db manager in QGIS 1.8.0 I can add the rasters to the map canvas. After moving the rasters to another schema in ...
1
vote
1answer
108 views

Area surface doesn't match

I have three municipalities with a total surface of 178 sq km. I want to analyze land cover of those municipalities using both LANDSAT images with a pixel size of 30 x 30 meters and SPOT with a pixel ...
1
vote
2answers
4k views

Can ArcGIS Desktop stack layers?

I have 7 bands of Landsat and I would like to combine all layers into one layer. Can ArcMap 10 do this like Erdas software can?
5
votes
2answers
385 views

Creating planes, eg roof surfaces, from LiDAR/DSM data

I am capturing the area of roof tops of buildings from a DSM (derived from LiDAR data) which has not been much of a problem. I can then also derive angle, hillshade and aspect but it is only ...
1
vote
1answer
815 views

How to convert multiple rasters to new raster (mosaic)?

I want to use Mosaic To New Raster in ModelBuilder. I want it to give me multiple outputs because I have multiple folders with a different number of images in each. Below is the model that I have ...
0
votes
1answer
382 views

How to create a raster mosaic from many asc files

I am trying to create a raster mosaic (in ArcGIS 10.1) as I am working with many asc files - I am trying to put all the different tiles together in order to run a view shed analysis. I have been told ...
1
vote
0answers
225 views

PostGIS raster functions aspect and slope slow

I am trying to compute the raster and slope values from a DGM table (8184 x 5159) imported from tif file tiled in 500x500 tiles. In my query in which I merge the DGM table with a vector (point type) ...
1
vote
1answer
365 views

ArcGIS TabulateArea() :: Recommend Ratio of Zone Area to Value Raster Cell Size?

Any recommended ratio of zone area / raster cell size when running small input zones with ArcGIS Tabulate Area Tools? Esri mentions: If the zone input is a feature dataset with relatively small ...
3
votes
0answers
58 views

simple raster format to use in Web applications?

I'm building a Web application in which users create and edit very coarse raster data. They're assigning values to cells in a georeferenced grid. Right now I'm storing the values in a multidimensional ...
1
vote
1answer
50 views

How to export Std Dev from Raster Dataset of DEM to classify current extent and execute Contour Tool with Python?

I want to create Countour Lines for a DEM which are based on a "STD dev" classificaion. My problem is that the "Std dev" is exported in an unknown type instead of a String. So the classifacation for ...
0
votes
0answers
298 views

Assign spatial reference for 1000 different ECW raster datasets using 1000 different *.prj files through python programming or .net

I am having 2000 ECW raster datasets without spatial reference and also I have 2000 *.prj files in another folder. I know only the way as right click on raster datasets-->properties-->Spatial ...
0
votes
2answers
362 views

What causes ERROR 000732 from MosaicToNewRaster?

I'm trying to run the MosaicToNewRaster tool as part of a python script. This is my code: input_rasters = arcpy.GetParameterAsText(5), arcpy.GetParameterAsText(6), arcpy.GetParameterAsText(7), ...
0
votes
1answer
120 views

How can I establish patterns, hotspots and clusters?

AS a crime analyst you need to establish a few maps that would help police to do targeted patrols, I've given data of suburbs, roads, incidents, boundaries. How can I establish patterns, hotspots and ...
0
votes
1answer
265 views

Help loading Raster to PostGIS 2 .0

Similar questions have been asked, but since my reputation is not enough I am unable to comment on answers. (The following is from an answer by nickves for this question Loading raster data to ...
0
votes
1answer
558 views

How to batch merge rasters using FOSSGIS tools?

I'm working with QGIS 1.8 (gdal 1.9.2) and GRASS 6.4.3...but on Windows 7. I "just" want to merge my raster. I've got a folder with 50 GTiff raster from Lidar data. The aim is to merge raster ...
1
vote
0answers
170 views

Floating Point UniqueValueRenderer

I am trying to build a unique value renderer using ArcObjects .NET. All the samples that I have seen use the attribute table to build the UniqueValueRenderer. However, my raster does not have an ...