Rasters are regular grids of values, usually stored in an image-like format.
2
votes
5answers
314 views
Attempting to bring 2,300 .sid files into one raster
I've tried all of the raster tools within ArcToolbox with no luck having such a large number of files. There are about 7GBs worth of MrSID files totaling about 2,300. Most tools fail or process too ...
8
votes
2answers
560 views
Grid vs TIF vs IMG
As the title suggests both of the above three formats are raster files. In ArcGIS, apparently there's no difference between them. So what's the difference between these three formats?
2
votes
1answer
161 views
How to Calculate Utilization Distribution Overlap Index (UDOI) in ArcGIS 10?
I was wondering if any of you happen to have any information on how to calculate the Utilization Distribution Overlap Index (UDOI) in ArcGIS 10? If I understand it correctly the UDOI takes two kernel ...
2
votes
1answer
27 views
Clipping a raster in R
I am building a map for the northeastern U.S.A. The map background needs to be either an altitude map or a mean annual temperature map. I have two rasters from Worldclim.org which give me these ...
0
votes
4answers
53 views
How to clip rasterdata for later processing?
My need to dwell with geographical tools is only temporary, thus I am not well versed and my question is difficult to pinpoint exactly. But here it goes:
-I have about 5-10 sites, for which I need ...
0
votes
1answer
41 views
Field added to raster data is not visible in attribute table
I am new to raster data and my background is software engineering so this might be a trivial question for GIS specialists.
Some raster files have attribute table but some do not.
On those with ...
2
votes
1answer
109 views
USGS GeoTiff extent via GDAL
I have 2006 land cover GeoTiff from the USGS site (for a county in VA, USA). The projection is Albers Conical Equal Area Units. The download came with an HTML metadata file that tells me the geo ...
1
vote
1answer
28 views
Raster to polygon conversion's raster field takes only “Value”
Recently I am working with raster data and arcobjects.net. Here I find something new for me. And here some question arises in my mind. I tried to search some document that can satisfy my mind, but I ...
0
votes
1answer
29 views
value field name after raster to polygon conversion
When I perform Raster to polygon conversion using tool, sometimes it creates a field named "GRIDCODE", sometimes the field name is "grid_code". Why does it create random name of a field?
3
votes
3answers
67 views
Can a single raster pixel hold more than one value?
I am a newbie with raster data. Maybe this is a trivial question. Can a single pixel of a raster hold more than one value?
0
votes
1answer
35 views
Can ArcPy collapse layer in current data frame?
Online arcgis resource help provides a list of layer properties which can be used as needed. I am not able to find a way to collapse a layer using arcpy in it. Please suggest if there is a way to ...
1
vote
1answer
49 views
Problem loading raster to PostGIS using QGIS
I am having trouble loading a raster (.asc) file to PostGIS 2.0.1 using the plugin Database - PostGIS Raster - Load raster to postgis in QGIS 1.8.0 on Win Vista 64 bit. I get the following error ...
1
vote
1answer
23 views
Why does the Zonal Statistics tool always return 0?
I have a slope raster created from a DEM raster with the DEM Analysis tool.
Now, I would like to calculate the average slope in a given area represented by a vector polygon layer.
I thought I could ...
0
votes
0answers
16 views
Loading raster from PostGIS DB into QGIS: succeeded yesterday, fails now
I have a PostgreSQL(v.9.2)/Postgis(v.2.0.3) database which includes raster layers (added through raster2pgsql).
To open them in QGIS (v.1.8.0-Lisboa), the "Add Postgis layer" menu will not work; ...
2
votes
1answer
58 views
Zonal Statistics-Weighting
I have a raster file on precipitation and I want to create zonal statistics as a table using a shape file wiht boundaries of countries across the world. However it appears that I need to take into ...
5
votes
2answers
92 views
Creating randomly shaped clumps of cells in a raster from seeds of 1 cell/pixel?
As my title says, I wish to "grow" clumps of cells from seeds within a raster. My base raster is full of 1's and 0's, 1's indicate land and 0's sea/NA areas. From the 1's I wish to select 60 random ...
1
vote
3answers
67 views
How can I reclassify a raster to floating point values?
I have a raster of landuse values that I need to reclassify into pollution concentration values. I have the pollution values in a separate table. They are decimal values (ex. 0.0056), and my landuse ...
1
vote
1answer
44 views
Problem with calculating the total cell values
aa= arcpy.RasterToNumPyArray("water_depth")
sum = numpy.sum(aa)
print sum
-2933737
Why I am getting negative values ? In my raster there is no any negative ...
-1
votes
0answers
22 views
Generate files TFW from a text listings [closed]
I have a list with all dat that must have any tfw files. Anyone know if there is some tool to do this automatically.
2
votes
1answer
46 views
Raster Version of Spatial Join (one to many) [duplicate]
I have two raster layers that are identical in shape (they overlap exactly) and I need to perform the raster equivalent of a Spatial Join (one to many). My files need to stay in raster format ...
2
votes
1answer
42 views
Tabulate Area crashes Python and ArcGIS
I have a script that runs Tabulate Area on a single feature class multiple times with different rasters. In total Tabulate Area runs 5 times. 2 of the input rasters are provided as arguments to the ...
5
votes
3answers
1k views
Extract Raster Value into Polygon Attribute
I have Raster Data for a State which has Elevation Data in its pixels. I also have Vector layer which has the 300 divisions of State. what I need is, I want to get the average elevation value of ...
0
votes
0answers
34 views
How can i calculate the width of the dam?
I am working with Reservoir design. Now I am facing problem to calculate the width of the dam. I need to calculate the width based on DEM and height of dam at various points using Python. I am working ...
0
votes
0answers
22 views
GDAL: add metadata to Bands when creating new GeoTIFF
This is a metadata question :-).
I am processing airborne laser scanning full-waveform data to extract information and I store this information by creating a multiband GeoTIFF using GDAL. I will have ...
1
vote
3answers
61 views
Apply rotation before FeatureToRaster_conversion
I am converting polygon shapefiles to rasters. With arcpy I am using the function FeatureToRaster_conversion.
gp.FeatureToRaster_conversion(InFeatures, InField, OutRaster, InCellSize)
This function ...
5
votes
3answers
359 views
How do I use polygons to apply a unique value to all raster cells within those polygons?
In ArcGIS 9.3, I have a raster file that I would like to "mask" with polygons, giving a single value to all the raster cells that overlap the polygons. How can I do this? Here's a screen shot, where ...
1
vote
0answers
27 views
Different results from Spatial Analyst GP Tool and Python
I am writing a script that has to subtract one raster from another.
The rasters I have represent
1) Parking Lots (1 = Parking Lot, 0 = not Parking Lot) and
2) a buffer around the Parking Lot (1 = ...
1
vote
0answers
21 views
QGis Grid statistics for polygons error - Module caused access violation!
I'm trying to calculate statistics for a raster layer using an overlaying polygon layer, I'm using SAGA "Grid Statistics for polygons" function, but it returns an error, sadly.. So in the sextante log ...
4
votes
1answer
54 views
Raster to vector with gaps in Landsat ETM
I need to find size of water area from a raster (jpg) using QGIS 1.8.0-Lisboa. The raster is a Landsat image with gaps of data in it.
I used Polygonize, but the output file shows wrong polygon size ...
4
votes
1answer
241 views
Can I create a legend of a map that I had get from a WMS?
Can I create a legend of a map that I had get from a WMS?
Can I create a legend of a raster map with Qgis version 1.7.4, or only with the 1.8 version?
0
votes
1answer
22 views
Add a time dimension in ESRI mosaic raster dataset
I am in the process of creating a script to pull daily .asc files from a ftp server, convert them to a raster format, and push them into a mosaic raster dataset. Ultimately, the raster dataset will be ...
3
votes
1answer
39 views
Is it possible to batch clip rasters in Quantum GIS?
I have been able to batch clip rasters in one directory using python in ArcGIS. However, I am not sure how to do the same in Quantum using the python console. Is this possible? If there are different ...
-2
votes
0answers
18 views
ArcGIS 10.1 Data Driven Pages Raster Rendering from Current extent
Data Driven Pages are not honoring the Raster Rendering by current extent when exporting multiple pages to pdf. The current map page works fine, but subsequent pages use the same color rendering (ie ...
0
votes
1answer
22 views
Extraction of raster cell values based on 'rgeos' and 'raster' buffering approaches in R
I am trying to extract cell values from a raster that lie within a certain distance from a given location (i.e. buffering). Evaluating different approaches, I found out that applying gBuffer(..., ...
3
votes
1answer
661 views
Polygon to Raster Tool Problem
I am trying to create a raster data set from county level polygon data for the US. I have successfully created one raster from a dataset, but when attempting another, it does not work. I am ...
1
vote
1answer
29 views
Calculating Volume of Reservoir using python and ArcMap10? [duplicate]
I have a raster file with different water depth in each cell. I am using Aster DEM so my resolution of that file is 30m by 30m. Now I want to calculate the total volume in that area by multiplying ...
1
vote
0answers
19 views
How to combine two rasters, preferring the values of one over the other? [duplicate]
I have two rasters that I need to combine (not using the Combine tool). The values of the 1st raster are preferred to those of the 2nd raster, so I want to keep these values if they exist. Where the ...
1
vote
1answer
108 views
Stuck in loading raster to PostGIS
I am running running Mac OS X (10.7.5), PostgreSQL (9.2) and PostGIS (2.0.2) (installed via Postgres.app).
The PostGIS extension seems to work perfectly with vector and raster layers. Once I enable ...
0
votes
0answers
21 views
Sum all cells in raster using javascript
I'm creating an agent-based model in Agent Analyst for ArcGIS and I need to sum all the values in a raster that has about 7 million pixels. I'm a very beginner in programming, and have a script that ...
16
votes
3answers
293 views
How to represent trend over time?
I have a time series of rasters where the cells of each raster represents some value at a certain time.
I'd like to generate a map that highlights the magnitude of positive or negative trends in this ...
0
votes
0answers
26 views
Raster attribute field error [duplicate]
I am trying to add jpegs to a raster data type attribute field. I want to this field to be managed by the file geodatabase. When I load the photos and try to save my edits it get various errors but ...
0
votes
0answers
15 views
GDAL Utilties - Multiple Bands with Different Output Types
I have a raster dataset with 5 bands. 4 of the bands are 8bit unsigned and the 5th band is 32bit floating point. I need to clip the dataset into tiles using GDAL (I'm using gdalwarp with a cutline ...
0
votes
0answers
26 views
Explaining the output from ArcGIS' Principal Components tool
I have completed the process but am unsure whether I am interpreting the output like I should, particularly the text file. I am especially interested in the "EIGENVALUES AND EIGENVECTORS" portion.
5
votes
3answers
2k views
Quantum GIS and ECW images?
How might I enable Quantum GIS to read ECW imagery?
At the moment I'm mostly concerned about this on Ubuntu 10.4 amd64, but I also use WinXP & Win7.
4
votes
2answers
56 views
How to extract values from rasters at location of points in R?
My question is about extracting values from rasters at the location of points. With the function extract this is very easy, and the function gives me a dataframe with the values of all the variables ...
1
vote
2answers
5k views
How to calculate Raster Area per Polygon?
In ArcMap, I have a raster file that contains 6 classes of landcover and a shapefile that is the census data (OA boundaries and their population).
I want the area of each class in each OA? For ...
1
vote
0answers
107 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: ...
2
votes
1answer
46 views
Web mapping application with time slider and raster data
I need to create a web mapping application that can show raster layer of historical maps with a time slider.
Basically, something like this: http://goo.gl/GYHOX
I have different maps of different ...
1
vote
1answer
44 views
Grass7 - r.regression.multi and new raster
I am on the learning curve with Grass7. I managed to make r.regression.multi work, but there is one thing that would be of high interest for me: it is possible to create a new raster showing the ...
6
votes
3answers
110 views
How to efficiently read and reclassify many rasters in R
I've been tasked to create a suitability analysis of wave conditions in the Gulf of Mexico. I have 2 thousand or so raster files that are about 8 MB each (2438 columns, 1749 rows, 1km cell size). ...
