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

learn more… | top users | synonyms

0
votes
0answers
18 views

Calculating maximum mean temperature of the coldest month with a lists of rasters

I need calculate the maximum mean temperature of the coldest month. I need first select the coldest month in a list and then in this month determine the maximum temperature. I do this: Create the ...
0
votes
0answers
12 views

fail to convert polygon to raster

I have a shapefile with 520 districts each with a value. I am trying to convert this shapefile to raster using feature to raster tool. Input feature: myshapefile Field: value Output raster: ...
0
votes
0answers
18 views

Maxent does not create the distribution map

I've been using Maxent to run a model, the program produces multiple output files except the html file, the map pictures and the distribution map or raster file (.asc). Does anyone know why this could ...
0
votes
1answer
34 views

Enabling: Raster and Topology

I'm new to GIS and tile servers. I've installed TinyOWS pretty successfully except for what looks like to be some dependency issues. I have installed PostGIS and also PostgreSQL. PostGIS is supposed ...
0
votes
0answers
36 views

NDVI from raster to vector isnt working

I have question...can I make from raster img. vector file via qgis? Because Ive tried it on NDVI image and Ive only got one file with atribut table full of #null. Image is from landsat7... ...
0
votes
0answers
30 views

Obtaining NDVI data from selected area

I need to analyse NDVI (-1/1) change between years (05-10y). But still only under selected shapefile. To analyse the extent of each NDVI category. Any tips? I have tried to make vector from the NDVI ...
0
votes
0answers
15 views

Raster alignment terminology?

I identify two types of raster alignment (assuming SRS is the same), but I am unsure of the correct terminology for these (or whether there is even a 'standard')? First, there is 'pixel alignment'; ...
0
votes
0answers
21 views

plot rasters with the same line diagram

I have 6 raster files with continuous values for an area with the same extent. I have created a raster stack and I want to plot one line for each cell in the raster stack of my six rasters (like the ...
0
votes
0answers
12 views

Dynamic polygons grid with specified area based on raster

I'm interested if anyone have idea how to automatically create (maybe in R?) dynamic grid of polygons with specified approx. area (for example around 20000 m2) based raster data or points with values ...
0
votes
0answers
28 views

Converting NAD 83 to WGS 84 in PostGIS

My question is about the best way to convert from NAD 83 to WGS 84 in PostGIS. I have a PostGIS DB containing National Elevation Data rasters. The rasters are in NAD 83 and I would like to convert ...
0
votes
0answers
17 views

Raster data for maximum temperature

I am looking for raster data for maximum temperature, ideally on a state by state basis (US) to make the file sizes smaller. Data would need to be weekly or daily going back to at least 2010. I ...
0
votes
0answers
15 views

Using USGS Raster Split but getting errors

I am working on an issue where I am trying to split the 2011 nlcd .img file into counties. I am really just looking at the midwest, so I have state county shapefiles for IA, OH, MN, MO, IL, IN and WI. ...
0
votes
1answer
18 views

arcpy CSV file to raster attribute table?

Using TableToTable_conversion I can convert a CSV file to a table in a geodatabase, but how can make this table be the default attribute table for a raster in the geodatabase? I can't seem to find ...
0
votes
1answer
33 views

Align pixels from two rasters with different cell sizes

I have two rasters in a PostGIS database that I want to be able to compare. The first raster is at 5m pixel resolution and the second raster is at 30m pixel resolution and is on a different grid. How ...
0
votes
0answers
17 views

Creating ROIS in Semi Automatic Classification pluggin Qgis

I am trying to classify a Landsat 8 image using the semi-automatic classification plugin in QGIS 2.6. When trying to define ROIS, I select a pixel of of interest, but the polygon is created ...
0
votes
1answer
23 views

Compare two rasters in R with the cell value from one replacing the cell value from another

I am trying to create a single raster from two rasters. The first raster is made up of all 0 values and the second is made up of the current date value (formatted in days from 001 to 365). The problem ...
0
votes
1answer
29 views

Output Raster r.cost.full values

I am having troubles interpretating the output of r.cost.full. Currently i am working on a project comparing some arcgis tools with qgis tools (workflow and output). One of my examples is to make a ...
0
votes
0answers
51 views

Raster (Tiff) to KML for Google Earth Overlay - QGIS

I am trying to convert some raster files to KML in QGIS for overlay in Google Earth. They are really huge Tiff files as I processed them from 3 meter DEM datasets. I have been searching the web and ...
0
votes
0answers
29 views

Draw gridded lines inside a feature and generate random points

I have several vectors containing features that originated from a 30 x 30 m raster. I want to generate a grid of lines (fishnet) in all of the features that are more than 30 x 30m. As shown in the ...
0
votes
1answer
37 views

Combining multiple overlapping rasters - retain maximum value?

I have 40 overlapping raster grids (derived from flood modelling software) that I want to combine in such a way so as to retain only the maximum value in any of the given rasters at each grid ...
0
votes
0answers
27 views

'combine' more than 20 raster bands

I have overlapping polygon data that I would like to 'combine' in ArcGIS and I'm running up against the 20 band maximum for rasters. I'm interested in solutions using this basic method with Arc or ...
0
votes
2answers
57 views

Extracting multiple values of raster to polygons using ArcGIS for Desktop?

I was hoping I could get some help on how to extract information from a land use raster using polygons. I have a layer with 157 polygons and a land use raster with multiple land use categories for the ...
0
votes
0answers
25 views

Merging DEM files using PostGIS

I have several DEM files and I want to merge them to create a mosaic. I found the St_Union(raster) or St_MemUnion(raster) functions but I don't know how to use them. Are there any other solutions?
0
votes
0answers
17 views

polygonize some raster pixels based on their value in PostGIS

I need to extract and polygonize only those pixels of a raster that have a value (e.g.) greather than 2000.0 The reason is that I wish to do an operation like the following one (which is done only on ...
0
votes
0answers
35 views

Calculating where the Z values of two rasters intersect

I have several raster layers which are depth horizons, one of these horizons cross cuts the others and I would like to calculate the line along which this occurs. i.e. the line along which the Z value ...
0
votes
0answers
21 views

Merging - Aggregation of Rasters

I'm a beginner in Java and a geomatics student. I'am using IntelliJ and I work in Java. I create two raster with the BufferedImage Java class. Raster1 Raster2 These images show for raster1 the ...
0
votes
0answers
25 views

Zonal statistics as table failed

I'm using ArcGIS 10 to perform "Zonal statistics as table" for my raster data (temperature). I would like to know that for each 50m level (for example, 0-50m), what is the average temperature. ...
0
votes
0answers
19 views

Add feature data to raster to see where it occurs relative to depths in cross-section?

I have depth soundings in which I have used IDW to generate a continuous raster surface to display bottom contours. A hillshade was generated to display in addition to generation of a TIN and ...
0
votes
0answers
15 views

Select raster using in line variables

I am trying to select rasters based on an in line variable to insert such raster into raster calculator within model builder. However, when using the select data tool it does not allow for ...
0
votes
0answers
23 views

Why are my block neighborhoods not square?

I am running block statistic on a couple of binary rasters. Everything seems to be working fine, but the blocks are not oriented with the rumb lines of my projection. They're tilted about 40 degrees ...
0
votes
1answer
28 views

Growing error from west to east when overlaying raster and shape

I am using a shape of Austria from gadm.org which I want to overlay with a netCDF file in R. As the netCDF has projected coordinates in EPSG:31287, I have reprojected the shape using FWtools and the ...
0
votes
0answers
61 views

How to interpolate raster to get finer resolution?

I am working with precipitation raster layer. It happens the raster data to be in a resolution of 0.25 degrees grid. How could I interpolate those pixels to have a better resolution, say, a resolution ...
0
votes
0answers
41 views

What can I do to reproject rasters without modifying the original values?

I downloaded a series of Landsat 8 Images and I will be using QGIS to process them. The projection of 2 of them are incorrect, so I used "Warp tool" in QGIS to change them. The resulting rasters DO ...
0
votes
1answer
31 views

Creating polygon layer from raster

I am using ArcGIS 10.2 in order to create soil management zones for farmers. when I use the raster to polygon tool it creates small triangles out of the polygons and jagged edges that are very ...
0
votes
0answers
8 views

Performance: Reproject Cache vs. Drawing Vector data in correct projection

I have quite a bit of data that I am caching from UTM to Web Mercator. This is fine, but I have another process that automatically creates map book pdfs. These map books have been setup to read the ...
0
votes
0answers
27 views

strange raster calculator behavior in QGIS

I used to work with qgis 2.8.1 in Lubuntu and in windows7. Each time I try to multiplicate a map for a number comprise between 0 and 1 (i.e. 0.1) I get a good results on windows OS, but I get a map ...
0
votes
0answers
33 views

NetCDF calculations

I have a raster of monthly average temperatures for the state of TX (represented as a grid) for a 50-yr period in the form of a netcdf file. I can display the temperatures but am not sure how to do ...
0
votes
0answers
28 views

load raster (geotiff files) to postgis with url

I tried to load rasters to postgis with raster2pgsql but this not satisfy my project because it uses local files. i have 5000 and will be more in future geotiff files in cloud host. is it possible ...
0
votes
1answer
39 views

Importing large tiled datasets (e.g. Ordnance Survey) into MapInfo?

I am currently using MapInfo and have several large Ordnance Survey datasets, which require updating. They are tiled .tiffs and need to first, be registered as .tab files. Second the .tab files need ...
0
votes
1answer
47 views

How to update raster color ramp with new min/max values using PyQGIS?

I'm trying to update a single band psuedo color renderer with new min/max values from the python console. All the code samples i have been able to find deal with constructing a renderer from scratch, ...
0
votes
1answer
103 views

How to fill holes/missing values in XYZ data / a DEM with QGIS?

I have equidistant XYZ point (text) data that I used to create a point grid. However, it's not perfect - there are some holes. I then created a DSM raster from it, which obviously has the holes too. ...
0
votes
0answers
25 views

Creating a for.loop to randomly extract data from a raster stack within shapefile extents

I'm currently comparing a MODIS time series of about 15 years to determine the effects of pasture management practices on the "greeness" of pastures in a water catchment. So far I've been able to ...
0
votes
0answers
99 views

Computing Area Weighted Average on Rasters Using Raster to Polygon

I am using ArcGIS 10.3 for Desktop. I am trying to compute area weighted averages for polygons in a shapefile using values in a single band raster data set. The approach I am taking is that I am ...
0
votes
0answers
61 views

GDAL: defining nodata value for gdal_calc.py

This old post exactly describes my question: http://lists.osgeo.org/pipermail/gdal-dev/2011-September/030281.html I want to copy the numpy ma.masked_outside functionality to mask values in my ...
0
votes
0answers
8 views

Raster loading on arcgis javascript api on user request

In my project, i want to give the user the option to select the date of the raster he/she wants to display, then that raster would be loaded onto the basemap. I loaded daily raster (CREST hydrological ...
0
votes
0answers
56 views

How to process a big number of raster outputs with r.series?

I am new to python and QGIS. I'm trying to take some simple operations (e.g. count, average) over a big number of raster maps from a python script. I'm using the "r.series" algorithm (from processing) ...
0
votes
0answers
23 views

Different colors of rasters after loading back to QGIS

I am experiencing this issue longer time but sometimes it is really annoying so I would like to solve it. When I save an image from QGIS - no matter when using Project/Save as image or using Export ...
0
votes
0answers
12 views

fit polynomial function on spectral data

I want to fit a polynomial function (max. 3rd order) on each raster cell over all my spectral bands (Landsat 1-7) creating a new raster(stack) representing the coefficients. I got my data (including ...
0
votes
0answers
36 views

Is it possible to put a raster layer on a shifted Chinese basemap using leaflet API?

Recently, we want to develop an application with leafleat and gaode basemap because some features of these products fullfill our basic needs. We want to overlay some raster layers caculated by spatial ...
0
votes
1answer
38 views

Extract by Attributes in Model Builder, “Table Name is Invalid”?

I'm attempting to use "Extract by Attributes" in model builder as part of a larger model. I'm trying to pull 6 different attributes out one by one in order to create random points within their areas. ...