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

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2answers
2k views

Calculating area of rasters in QGIS?

I have been working with some rasters and would like to know how to calculate the area occupied by one element of a raster in QGIS?
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3answers
122 views

How to extract values from raster at points with many different rasters and points

I have a folder containing 100 DEM rasters. I have a point file containing thousands of points. I need to collect raster values at all of these points. Only some of the rasters intersect with the ...
8
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6answers
4k views

Continuous color band for a raster legend in QGIS composer legend

I'm looking for a way to insert continuous colour legend for a raster layer. I managed to create discrete symbols with values along the bar, but I would like to have a continuous bar with some values ...
4
votes
1answer
151 views

Convert raster to smooth contour polygons in QGIS

I have had limited success creating smooth contour polygons from a raster layers. I have created contour lines and boundary polylines and then used QGIS Union. Then I use QGIS Polygonize. Then ...
2
votes
1answer
47 views

Calculating raster area by converting to points to account for latitude changes?

I am looking at a large geographic area (e.g., continental Africa). I generated a raster of modeled habitat (using MaxEnt) defined in WGS 1984 depicting the hypothetical distribution of an organism at ...
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0answers
136 views

Georeferencing google earth historical images

I have been trying to raster and georeferenced an historical set of images from Google Earth but I am experiencing issues after done the first one properly. I save 4 images from Google Earth of the ...
5
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1answer
74 views

Stratified Random Sampling Tool

Is there a way to produce a certain amount of random points over different classes in a raster in QGIS? I have extensions such as GRASS or GDAL, ...
1
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1answer
38 views

GRASS/QGIS- “buffer” created with DEM analysis- how to avoid it?

I have, to start, a DEM raster and a shapefile, with random created points, within a given polygon. The DEM raster was clipped with that same polygon. With the DEM raster, I used GRASS to perform ...
3
votes
2answers
225 views

Automatic selection of pixels, from a raster series, greater than minimum image of the series

Given a series of rasters, and the raster image of the minimum values of the series, I am looking for a python script capable of selecting, for each raster, the pixels whose values are greater than ...
1
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0answers
31 views

ArcGIS how to geolocate/georeference raster data arrays?

How does one geolocate (or georeference) a raster of swath grided data with separate lat/lon arrays and multiple data bands using ArcMap 10.3? A sample data file (*.h5) can be downloaded from here ...
0
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1answer
53 views

How can I blend DEM rasters with GDAL?

I have several DEM rasters in different projections and at different resolutions. The rasters are not rectangular, but they have appropriate NoData values. They overlap enough that I should be able ...
1
vote
1answer
54 views

Extracting multiple raster data to point shapefile in ArcGIS ModelBuilder?

I used raster iterator tool in ArcGIS ModelBuilder read several raster files in IMG format and extract values of corresponding raster files to a point Shapefile using "Extract multiple values" tool in ...
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2answers
25 views

R: Overlay using functions containing if/else statements

I have two rasters, x and y, and I'd like to do calculations with them using the overlay function. For example, MyFun <- function(x, y) x * y res <- overlay(x, y, fun = MyFun) This seems to ...
2
votes
0answers
22 views

classify colourramp with new min and max value with python

For my script i want to update the existing colourramp of a raster with new min and max value. In my current code is can fill the min and max but can't classify and update the raster. How does the ...
2
votes
1answer
2k views

Better way to get raster values for a large number of point features?

I have several projects with tree point features (SpecialStatusSpeciesPoint) that contain up to 2,000,000 records. I am trying to record tree height (Hgt) and base elevation (BaseElev) values, based ...
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0answers
24 views

Geoserver Dynamic Raster Masking Based on Request Parameter

Is it possible for Geoserver to dynamically mask out values above or below a certain threshold in a WMS or WCS Geo-tiff request? For instance I make a request with some threshold parameter like 49 ...
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0answers
24 views

Convert a SHP file set to a categorised ASC raster with Qgis?

I have a shapefile with regolith (soil) data that I would like to use as a categorised raster (say 007_1ASC) in Maxent. The regolith data is in the following files: 007_1.cpg 007_1.dbf 007_1.prj ...
2
votes
1answer
25 views

How to extend an OSM or raster area in Qgis (into 'No Data' area)?

I need to do the opposite of clipping down a raster (or SHP file) in Qgis (or Gdal, Python etc - even R if someone can provide the script). I have a dataset from Open StreetMap (*.OSM) which includes ...
5
votes
2answers
2k views

Round Raster to next higher or lower int

I am using ArcGIS 10.1. I am searching for a solution to calculate a raster. The values are like: 0.2 0.6 5.3 i.e. How can I now get 0.2 as 0 and 0.6 to 1 and 5.3 to 5? In the end integer numbers. ...
1
vote
2answers
512 views

How to set the cell size of a tiff to 1 meter when working in a Geographic Coordinate System?

I am working in a Geographic coordinate system in ArcGIS, and I need to create TIFFs by exporting rasters. THese .TIF file must have a resolution (cell size, or GSD) of 1 m. Is it possible to set any ...
0
votes
1answer
31 views

Converting raster data from netcdf to image

I'm rasterizing some wind data from oos.soest.hawaii.edu/erddap/griddap/NCEP_Global_Best to use as an overlay of a final image, but I'm having issues calculating the bounding box of the final image. ...
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0answers
49 views

KML with raster in QGIS

I have a kml file which displays correctly in Google Earth but only as a bounding box in QGIS . What can I do to see the associated raster image?
0
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1answer
35 views

How to create or reclassify a land cover raster based on distance to roads in ArcGIS 10.4?

I am using a raster of land cover (Globcover 2.2, 300 m resolution), which I managed to reclassify (in 2 land cover categories) and clip to my region of interest. I also have a shapefile of the roads ...
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1answer
60 views

How to delete one band from raster file?

I was working using drone imagery (regular camera) and there is this alpha band which is preventing me from doing maximum likelihood classification. I want to remove the alpha band. So far I used ...
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0answers
15 views

Converting radiance raster values to luminance

I have two nightlight data layers of the same area, one is a VIIRS radiance raster (the raster values are radiance values in units of nanowatt/sq.cm/sr) and the other one is a point vector luminance ...
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0answers
29 views

Raster to categories to shapefiles

I have a raster data file which is the population density. I would like to transfer this raster into a specific number of categories, let's say 5. After that I would like to convert the raster to a ...
2
votes
1answer
66 views

Update raster color ramp with new min/max values using python?

For a script, I want to update the exsiting min and max of a colour ramp with a new one. In the image you can see what I want to update. To do so I tried to follow this thread. I tested the ...
2
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0answers
39 views

Comparing areas of two raster files

I need to compare the areas of two rasters for calculating the percentage parts from another. For example, I have one raster file which shows separated agriculture fields. The value of each field is 1 ...
1
vote
1answer
36 views

QGIS- extract raster information into a point return nulls

I have a 1) raster layer and a 2) point layer. I want to extract the pixel value to each point, but it is not working when using this tools (QGIS): plug-in "Point sampling tool" (the new shapefile ...
0
votes
1answer
27 views

How can I combine together cells within the same raster in ArcGIS 10.2?

I have a raster displaying Land Cover data for the UK at a cell size of 25m. The cells are currently categorised as one of 24 different types of land cover. Some of these are irrelevant to me, and ...
2
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3answers
3k views

QGIS - extract raster values greater than 0

How can I extract values > 0 from an overall raster? I have a water level grid and a DTM from which I've derived flood depths (using the raster calculator) but obviously the final result contains ...
0
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2answers
1k views

How to round up/down an pixel value of a raster to a pixel value with 2 decimal places?

I have a raster (DTM) with floating points as pixel value. Now i want to round up/down the pixel values (to its next nearest value) to 2 decimal places. I use ArcGIS (with extensions) and tried the ...
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0answers
10 views

GRASS t.register (ERROR : maps= et file= sont mutuellement exclusifs) [maps and file = are mutually exclusive]

Je souhaite créer un strds. Pour cela j'ai créé un jeu de donnée à l'aide de t.create, puis j'utilise t.register pour ajouter deux cartes raster à mon jeu de données. Voici la commande que j'effectue :...
0
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2answers
121 views

Creating new raster based on spatial extent and classes of one raster and average of another using ArcMap?

I have a raster that is split into classes and I wanted to make a new raster with this raster's spatial extent and classes but displaying the average values from a different raster. I am not really ...
2
votes
1answer
43 views

Mapping raster values to nearest grid cell on a polyline

I'm not sure if the following task is possible in ArcGIS, or whether I need to use something like MatLab - I wondered whether the community could possibly advise if it is possible, and if so, what ...
1
vote
1answer
26 views

I keep getting the same error when trying to clip a raster

Error: Cutline feature without a geometry. Consistently get the above error when trying to clip a raster. I have looked at all the other questions relating to this and tried all the 'fixes' however I ...
2
votes
1answer
73 views

How to convert raster (big size) to points?

I have a raster : population density of Ivory Coast. I need to convert it to points, but I met several problems because of the size I think. Here is what I tried : 1) GRASS GIS 7 command : r.to....
1
vote
1answer
137 views

mask raster with shapefile using gdalwarp/gdal

I am struggling to use gdalwarp with cutline option. The following command keeps failing and I do not understand why : gdalwarp -cutline shapefile.shp file.tiff newfile.tiff Warning 1: Self-...
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0answers
53 views

How can I prevent gdal_translate from rounding coordinates when clipping?

I want to clip a raster (a VRT of several Ascii files) to a set of coordinates. Ideally I'd like to use gdal_translate to do this, but I only get an accurate result when using gdalwarp. gdal_translate ...
6
votes
2answers
3k views

Count number of unique raster pixels in polygon using ArcMap?

I have a polygon shapefile and I want to generate a table of a count for each pixel value in each polygon. My main goal is to find out what pixel is most abundant in each polygon. I am using ArcMap ...
3
votes
1answer
34 views

Configuring Project CRS to reflect degree coordinates

seems like this is a common problem, but posts with similiar questions did not solve my problem. I have close to zero GIS background so apologies for my ignorance. My goal is to extract only a ...
0
votes
1answer
19 views

ST_AsRaster for polygon

Having a hard time to get a raster from a polygon ST_AsRaster(ST_Buffer(ST_GeomFromText('POLYGON((-30 40, -20 30, -25 20, -23 10, -30 40))', 4326), 50),ARRAY['8BUI'],ARRAY[118]); This line is ...
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0answers
20 views

ST_AsRaster ST_AsTiff

Can someone give me an example how to use AsRaster and ST_AsTiff together? I am having trouble to create a tiff image. SELECT ST_AsTiff(ST_AsRaster(ST_Buffer(ST_GeomFromText('POLYGON((-30 40, -20 30,...
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0answers
50 views

Why is mosaic dataset such large file? [closed]

I have been trying to export a number of scanned paper maps onto my database, and have been just adding them as raster layers as part of a larger group layer. I georeferenced them, and none of them ...
1
vote
1answer
44 views

Displaying raster images using Leaflet?

The purpose is to create a small web application using an open source product, preffered Leaflet (but I will Switch the product if it works within another Framework than leaflet), simply showing a ...
2
votes
1answer
48 views

Rasterize points in a map : result is not leasible. How to make the raster (points) bigger?

I have a vector layer (points) that I rasterized based on one attribute of the vector layer. I chose the GRASS GIS 7 command : v.to.rast.attribute. The raster layer appears in the map, but is not very ...
2
votes
2answers
92 views

Webmapping option that allows rasters?

I'm trying to create an introductory GIS course that will involve an ideally simple web mapping component. I was underwhelmed that ArcGIS online doesn't support rasters, and surprised that MangoMap ...
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vote
1answer
30 views

Using ModelBuilder to create smaller individual DEMs from a large DEM using multiple polygon?

How can I use a polygon (which is made up of smaller polygons) to create individual DEMs from a large DEM using the polygons as the mask/extent? I am trying to do this in ModelBuilder and it isn't ...
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0answers
35 views

Error executing algorithm Clip raster by mask layer 'NoneType' object has no attribute 'GetGeoTransform'

Processing modeler: GDAL "clip raster by mask layer" tool I have a raster layer that I wish to be clipped by a polygon layer (buffer zone). I intend to repeat to process many times in a more ...
0
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2answers
39 views

Add raised features to digital terrain model in QGIS

I have a DTM onto which I need to 'stamp' a series of raised embankments. The DTM is a raster grid (in m above sea level) and the embankments are polylines containing the crest height (also in m.a....