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

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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?
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16 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 ...
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33 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 ...
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19 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 ...
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24 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. ...
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18 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 ...
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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 ...
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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 ...
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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 ...
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53 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 ...
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38 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 ...
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29 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 ...
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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 ...
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25 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 ...
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27 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 ...
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25 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 ...
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32 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 ...
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33 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, ...
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74 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. ...
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48 views

GDAL raster shifting with python error: 'NoneType' object has no attribute 'GetGeoTransform'

I'm trying to shift a georeferenced raster by 0.5m N and 0.5m W in QGIS using the python console: from osgeo import gdal # Open in read/write mode rast_src = gdal.Open('test_raster.tif', 1) # Get ...
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20 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 ...
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56 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 ...
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52 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 ...
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7 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 ...
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55 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) ...
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21 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 ...
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11 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 ...
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32 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 ...
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30 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. ...
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26 views

Is the QGIS connection with ArcGIS “mapserver” still working?

I would like to add the Ocean Basemap to QGIS. I also found the other posts and I followed this procedure: http://hub.qgis.org/wiki/quantum-gis/Arcgis_rest Hovewer when I put in the Python console ...
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59 views

Extracting point data for each lat and long from raster file into a dataframe

I have gridded data files ( see sample -each file consist of monthly precip and is label pYYYYMM) https://www.dropbox.com/sh/63z166tjxyu12s5/AAAs3Ccn1zdVoBYMj8Y1o303a?dl=0. I am trying to extract ...
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34 views

How to merge two rasters when are on the same place

I have two rasters in GRASS GIS. first : raster of DMR, raster picture of relief - created from high values second : raster of buildings where pixels of every building have value of high of this ...
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33 views

Weighted Overlay final raster to indicate inputs

I have a weighted overlay that identifies the most important areas in a corridor scaled from 0 - 100. I would like to be able to click on a cell and be able to identify which input rasters contributed ...
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22 views

Extracting many raster values for statistical analysis in JMP

To summarize: We have 28.5 million XY coordinates we would like to compare up to 6 raster values for, and prefer to look at those values in JMP. We are exploring interpolation methods in ArcGIS for ...
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31 views

Converting lat,lon & solar data in CSV to raster using Python?

I have a csv file with lat,lon and solar radiation data. I am trying to convert it to a grid/raster format so that it can be used with a raster population data set that is in ascii format. How can ...
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25 views

What format are raster data files with data, db, overpict, vect, and WMS folders?

I have a type of GIS data but I don't know what is this type or how to open them. My data are formed by 5 folders: data, db, overpict, vect, and WMS. The main folder (I think) is the first one; it ...
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34 views

Georeference a computed tomography image without changing its proportions in QGIS

I have several images obtained from a Micro computed tomography (mCT). The scanned elements are human teeth. In a particular mCT slice, I have introduced a cartesian plot with its X and Y axis. The ...
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28 views

change from NAD 1983 to some PCS?

I want to ask how to change the coordinate system from NAD 1983 to some Projected coordinate system. I tried to change this DEM file to WGS 1984 (all of them) but when I did that my scale becomes 1:4. ...
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30 views

Raster loading in web application

I'm making a GIS web application. I want to give the user the option to choose the raster to display on the map on the basis of date. I have daily rasters of 3 years. I'm using ArcGIS Server. Any ...
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1answer
38 views

Attribute table is missing in raster after using extract by mask tool

Every time I use the extract by mask tool, the rasters that are created don't have an attribute table (i.e it's greyed out). Does anyone know what is causing this and why these rasters essentially no ...
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48 views

Using ModelBuilder to Make Composite of NDVI Rasters in ArcMap?

I have got a large number of landsat raster data. I need to prepare composite raster and Ndvi rasters from the band Rasters which I have. I normally use Image analysis in ArcMap. I wanted to know how ...
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26 views

Analyzing homogeneity of raster values within polygons

I've been working with raster data of NDVI for agriculture plots. I'm testing the use of descriptive statistics (e.g. range and standard deviation) to observe any variations between plots (I think ...
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22 views

Error 010240 when calculating mean of a list of rasters - Cell Statistics

I'm trying to calulate the mean value of a list of rasters but I am always getting the following error: RuntimeError: ERROR 010240: Could not save raster dataset to < value > with output format ...
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29 views

weight a raster by another for a model ( R/ arcgis/maxent)

I have an idea in mind for my project but I can't figure out how to do it in R and Arcgis. Basically I would like to do a weight a raster by another for my maximum entropy model. -I got a raster ...
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12 views

joining attributes for .img files in erdas

I have numerous .img files of the same region and spatial resolution. In Imagine I would like to join all the attributes together into one .img that I may import into r for model predictions. Not ...
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60 views

How to separate details by color from raster?

How to separate details by color from raster? Is it possible in ArcGIS or any other software? I have tried Spatial Analyst. I want to use RGB .tiff image which is scanned map. It consists of all the ...
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23 views

GDAL Python and postgis raster?

I'd like to create a postgis raster using GDAL and python. I can get the driver easily: drv = gdal.GetDriverByName("PostGISRaster") But how can I create a new raster table? I can't find any ...
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22 views

Using mask to several raster datasets with same cell size, extend and row/column in ArcMap?

I have a raster dataset "substrate_W84" that I would like to use as a mask in order to create several raster dataset with the same cell size, extent, row/column (to be used in Maxent). ArcMap 10.0 ...
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26 views

Uploading raster to ArcGIS Server dynamically

I am building an new web tool related to agriculture research, this tool is linked to another backend GIS process done in c# and ArcObjects. I want to find a way to visualize this backend output ...
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13 views

Using QGIS to create a single # band raster Image [duplicate]

I recently downloaded some Landsat Images. They are in GeoTIFF format. The images are in the different bands. How can I combine them for example if band 1 is Red , band 2 is green and band 3 is blue, ...