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

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1k 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 ...
0
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2answers
377 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
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1answer
11 views

r.statistics throws invalid reclass rule error despite assigning null to unique value

Trying to run r.statistics on two raster layers, one a layer of distinct zones produced via r.clump (stands) and one a layer of all ones (ones). The areas outside of the immediate region of interest ...
0
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2answers
20 views

Problem with r.grow.distance on GRASS

I would like to use r.grow.distance on a raster map. I rasterised a shapefile (about 50 cities in a region) and we can see them on the raster map. Yet, when I launch r.grow.distance, I have a ...
1
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1answer
485 views

Convert Raster to Numpy Array with only Arcpy and Numpy

All the articles I'm finding including GDAL or PIL(?) which I cannot use. So I am trying to convert a raster I have to a Numpy Array with Arcpy and Numpy and then calculate some statistics on it but ...
1
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1answer
30 views

Applying symbology to raster layer in ArcPy without using symbology layer (layer file)?

I have a raster layer with 3 unique values (1,2,3) and I want to apply a unique color to each using RGB values or hex codes, without the use of a symbology layer (layer file). Is it possible to ...
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2answers
115 views

Get Raster Centroid using Arcpy

Purpose:To take an input raster image and clip its shape to a parcel block. In later stages this model will be applied to a loop. Logic: The Model receives an input raster image and calculates a ...
0
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1answer
14 views

Extract lat long point values from EASE2 without reprojection

I have the following file: EASE2 and want to extract the values for this geographic location (148.1, -35.6) #lon lat. How can I do this without the need for reprojecting the ease grid file into ...
2
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3answers
3k views

Coordinates of raster image from .TAB file

I have got a raster image (tif) from a mapping site and an associated .TAB file. I am trying to correctly map it into CAD/3d model - which I know is set up to the correct coordinates. The .TAB file ...
7
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1answer
388 views

How to store Large Raster Images of Equipotential Surface Generation Using Monte Carlo Simulation?

I have a large (1GB+) raster that I am using as the base for the generation of an equipotential surface. This is to assess the accuracy of DEMs derived from another source. In situ observation is ...
0
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0answers
8 views

Using predict function in raster package for applications other than species distribution modelling?

I was wondering if the species distribution modelling technique can be used to analyze other variables such as human movement. For example I have data on whether a person attends a facility (binary ...
0
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1answer
20 views

How to access to the underlying grid table behind Mapinfo's Grid Thematic map?

I created a grid thematic map using "Mapinfo - Map - Create Thematic Map" function. Now I want to know the distribution of the data from the grids. But the "Browse Table" option is not functioning ...
0
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0answers
15 views

Problem in cell dimension assignment from “save as” in QGIS

I am trying to save one raster in QGIS by changing the cell dimensions. I select 30 x 30 as cell resolution, but then the output raster has a resolution of 29.9985 x 29.9985. How can I assign exactly ...
1
vote
1answer
19 views

Can a Mosaic Dataset have rasters with different vertical units?

I am creating a Mosaic Dataset (ArcMap 10.3) that contains LiDAR dems from a number of different US states. The data is in different coordinate systems (UTM, State Plane meters, State plane feet), ...
0
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1answer
228 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 ...
4
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2answers
52 views

Precipitation data raster

I'm using the TRMM 3B43 precipitation data. I have downloaded individual NetCDF files depicting yearly accumulation in mm for each year from 2000 to 2015 (16 files). I have imported each file into ...
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vote
1answer
33 views

Sum area of specific poly attributes within raster grid cell

I have a polygon layer (A) containing several different land use types (road, building, etc). I also have a different GIS layer (B), a raster of NLCD land use/land cover. I would like to sum/...
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2answers
41 views

How to define season by month and average data

I have 10 year NDVI data i.e. two values per month. I would like to average values within a season e.g Season A (January, February and March) per year and plot a graph. y axis=average ndvi value, x ...
4
votes
2answers
176 views

How to model a geodesic grid in PostGIS?

Abstract I've decided to use PostGIS for a hobby game project. It requires a lot of units allocated on the surface of a planet. I'd like to model not only the units (simple points), but also their ...
3
votes
2answers
170 views

Generating an image representing inland surface water using QGis and OSM data

I'm trying to generate a raster image representing surface water for a given bounding box. I'm using OpenStreetMaps data as my input for water bodies, and I'm using QGis on Ubuntu to process this data....
2
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0answers
386 views

Intersecting vector data with raster data in PostGIS?

I have Open Street Map [OSM] data imported so that I can access the geometry of buildings. I have also loaded SRTM digital height data from NASA from a GeoTIFF raster. I have projected the raster into ...
3
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2answers
46 views

How can a statistically significant difference between rasters be calculated?

so after some gruelling use of MaxEnt I have four occurrence probability rasters for the four quarters of the year, each one is about 70MB+. I want to test whether they are significantly different ...
0
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2answers
361 views

Issues calculating range with QGIS 2.0 raster calculator

I would like to calculate a simple range using the QGIS 2.0 Raster Calculator, but am getting strange results. I believe I am not using the correct syntax. To get all values between .003-.5, I ...
0
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0answers
11 views

kernel density estimation-mask layer-arcgis

I have a vector layer with points (road accidents) and another polygon layer which is the area in which occured these accidents. I ran kde where I changed the environments-raster analysis (I added as ...
2
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1answer
40 views

QGIS Oracle-Spatial-GeoRaster-Plugin not working

I am having trouble with Oracle-Spatial-GeoRaster-Plugin in QGIS (running on Windows 7 Professional N 64bit). The connection to my database on an external Oracle-Server obviously works as it shows the ...
0
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0answers
21 views

How to create raster layer directly from numpy array in QGIS, without saving to file?

I have managed to create a numpy array from a raster file using commands from the gdal library, and now I would like to load that raster as a layer without saving it first. It seems like there should ...
3
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2answers
861 views

How to shift a raster in QGIS?

I'm looking for a tool or a plug-in for QGIS that would allow me to shift rasters to new coordinates. An equivalent of ArcGIS' Shift tool would be the best option. I know I can edit the world file ...
1
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1answer
41 views

How to make a loop that interates over large raster cells in R go faster?

I am trying to add +1 to the cell value of certain cells in a raster. I have the cell numbers of the cells on which I'd like to perform said computation saved in a vector. I have a working code but ...
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1answer
39 views

Rasterizing in R - how do resolutions work? (e.g. population within a circle)

I'm creeping into building surfaces - useful for a number of public health projects - and can't seem to make sense of what's happening with the resolution and raster building process to get what I ...
2
votes
1answer
209 views

Why am I losing part of my raster when I reproject?

QGIS 2.0 Working with tiff raster file. Reprojections are in WGS84 Mercator. Here is my problem: I am trying to use buffers or urban areas to analyze light intensity on a raster layer. I want 30 ...
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1answer
88 views

Max value of overlapping Polygons

Licence: Advanced Version: ArcMap 10.3 In my shape are thousands of overlapping polygons. My goal is, to generate a new output in which the biggest overlapping value represents a new polygon/...
9
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5answers
5k views

How to modify single Pixel values in QGIS?

I would like to modify a raster (pixel values) in QGIS. The plugins "value tools" can easily provide me with the value of the pixel of my raster. However I don't know how to modify it. I have found ...
2
votes
1answer
4k views

How to create attribute table for raster data?

I have raster dataset for rainfall but its not having attribute table. How can I create tabular data using the same raster file? How to join it back again to it? Software used is ArcMap 10.1.
2
votes
1answer
80 views

How can I change the origin (top left corner) coordinates of a raster using PyQGIS?

I am developing a python plugin for QGIS. The purpose of the plugin is to properly open an HDF5 dataset as a raster. Opening and displaying the raster can be done without the need for a plugin, ...
1
vote
1answer
360 views

How to use GDAL to burn a selected value from one raster into another?

I think this should be a relatively simple process, but I'm not quite sure how to approach it. I have a shapefile containing 1000's of polygons. I also have 19 rasters. All of the polygons fall ...
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0answers
15 views

Resolution changes when exporting raster from GRASS to Arcmap

I have a raster file of rainfall (floating) in GRASS that I want to export and open in arcmap. If I look for the raster file in GRASS, it has Rows: 140 ...
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2answers
110 views

Clipping a raster layer with a shapefile on mac

I am trying to clip a raster layer using the raster clipper function. However, for some reason this is not working for me and I haven't been able to find the answer anywhere. I choose my raster ...
0
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1answer
15 views

Receiving higher values than should be possible in stackApply SUM for Frequency calculation in R

I am currently working on creating a frequency raster for a country based on multiple Rasters of the same day through following years and where the previous values are reclassified to 1's and 0's. The ...
0
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0answers
22 views

Scanning a raster by moving windows. Output rasters off by a cell. ArcGIS, python

I'm working in extracting smaller rasters from a bigger one (yellow). I'm using only python, some numpy maybe. I succesfully extracted a patch from a big raster, secuentially, by moving windows. So I ...
0
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2answers
32 views

How do I convert a fire frequency point shape file into a fire frequency raster?

I have a point shapefile that I want to convert to a raster image using ArcMap 10.2. The shape file has a number of points on top of each other. Each point is a fire. I want to make a fire frequency ...
5
votes
2answers
3k views

How to create a catchment from a point using a DTM raster in QGIS?

I need to find a better way to delineate a catchment from a given point on a watercourse using a DTM - currently I am either using FEH, or if the catchment is too small using contours to draw manually....
0
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0answers
44 views

Why do merged rasters in QGIS look 'patchy'?

Poor title for this question, but I can't think of a better way to explain it. I have merged two rasters. I want the joins to be seamless, but there is an obvious line where they meet... I've ...
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0answers
28 views

Multiband virtual raster with gdalbuildvrt: Control how bands are sorted

I am making a multiband virtual raster using gdalbuildvrt. Everything works fine, but a little detail remains annoying: I cannot control how the bands are sorted. I specified the input raster using ...
6
votes
1answer
86 views

Is it possible to use a raster::click event within an interactive leaflet map?

Data Download: https://www.dropbox.com/s/f849ra8l6umo9d8/crops.tif?dl=0 I have various raster images of the world that I would ultimately like to plot within an interactive leaflet map; an example is ...
0
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0answers
15 views

Perform supervised classification on SAR image in SAGA GIS

I tried working on supervised classification on SAR data in SAGA. I am confused about creation of training data. How can I create Training data for my SAR image?
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0answers
12 views

Calculate Worldwide Raster area (30arcsec, WGS198) [duplicate]

I have a worldwide raster dataset (30 arcsec, WGS1984) with 11 Landcover classes. My goal is to calculate the extension for each class. I´m using ArcMap 10.1.3. So far I projected my Raster in ...
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1answer
18 views

How to select a fixed dimension ROI in ENVI?

ENVI provides the freedom to select ROIs by drawing polygons etc. I want to clip a fixed size ROI, say 512 x 512 in size. Is there a way to do that?
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0answers
47 views

Extracting data of two overlapping rasters

I am trying extract the data of two overlapping set of rasters (one, a stack of 35 rasters, all from the same source and the second an elevation raster) to get a data.frame of the values (mean of the ...
0
votes
1answer
24 views

Set projection (netCDF) with R-ncdf4-Package

I want to create a netCDF-file that has a defined projection ("WGS 84 / UTM zone 32N") with the netcdf4 package in R. The input float array has the size of x=880 and y=760. So i define the two ...
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1answer
45 views

Extracting small numpy array from a bigger raster, by moving windows. Memory issues. ArcGIS

I'm trying to extract a small raster from a bigger one, just using python and numpy (I'm not allow to use any other software). This code just reads a from a big raster, extracts an smaller window, ...