Tagged Questions

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

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3
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1answer
410 views

Re-project raster image from Mercator to Equirectangular

I have a raster image of the world map in Mercator projection, square 1:1 format. I want transform the image into an Equirectangular projection accurately. I assumed from my research that GDAL would ...
0
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0answers
118 views

Make a raster with pixel scale 100 by 100 meter with gdal_rasterize

I'm asking here, because, I've got great results last time. Here it is the next of my adventure with gdal_rasterize, I want to make a raster picture where each pixel correspond to a square of 100 by ...
3
votes
1answer
64 views

Why is Mosaic or Mosaic To New Image causing a 1-pixel gap between adjacent images?

I have a series of adjacent PNG images, and I'm trying to merge/mosaic them into a single seamless image. The images have clean "cuts" between them, with no overlaps. However, when I use either the ...
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2answers
217 views

How to display a raster using Javascript API

It's all a proof of concept for myself and my learning but I have definitely hit a brick wall here! Here's what I've done and can get to work. I have written a Python script that: Sets its ...
0
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1answer
56 views

Associate points with polygon QGIS 2.2

I want to associate a point layer with a polygon layer so that I can do zonal statistics. In the image below, the polygon layer represents roughly the metro area of a certain city. The point ...
2
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2answers
305 views

Conversion of point grid to a raster with open source tools (Gdal, QGIS …)

I'm looking to do something which seem simple to me, but I haven't found a solution since 2 days I looked for. I've got a Postgis DB with lot of points (WGS84) spaced of 100 meters which cover a ...
2
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0answers
50 views

How to normalize multiple PNG rasters with differing colormaps

I have a series of adjacent rasters which comprise a digital elevation model. Unfortunately they have been given to me as PNG files, rather than Esri Grids. The only key that I have to the actual ...
0
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1answer
96 views

I'm converting a raster to TIN and a large section of it didn't convert properly (ArcGIS 10)

I've got a DEM for a pretty large area and I need to create a TIN. I'm using 3D Analyst Tools > Conversion > Raster to TIN. The process runs without any error messages, but a large section of the TIN ...
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0answers
42 views

How to accurately join data based on 1x1 degree grid-cell points to a shapefile

In the data file each row represents a country and a grid-cell at 1x1 degree resolution, and the given coordinates, in longitude and latitude, label the south-west corner of the grid-cell. The ...
2
votes
2answers
42 views

Delete numerous NoData rasters from database

I've got >1000 rasters in a folder with about 10% containing no data. I'm looking for a method, preferably through ArcGIS (also open to QGIS, GDAL, etc.), to run through the folder and delete all of ...
2
votes
1answer
247 views

Mosaic Aerial Photography Tiles to a Seamless Raster

I've got about 6 different Aerial Photography datasets I am managing at the moment. All of them are made up of tiles covering a large area. Some of these datasets contain up to 2000 tiles. All the ...
0
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2answers
117 views

Find the minimum elevation pixels from an elevation raster using arcpy

I want to create a python script to find the minimum elevation pixels from an elevation raster (aster,srtm) using arcpy and arcmap 10.1. The purpose is to reclassify these pixels. I have tried but I ...
1
vote
1answer
72 views

How to set the output extents of rasterization in QGIS

I am trying to rasterize a bunch of vector based shape files in QGIS. All these files are covering certain types of ground use in a city (houses, street, open field,...). I need these files to be ...
0
votes
1answer
187 views

How to remove black box around georeferenced grayscale image in QGIS?

i'am trying to georeference a grayscale image (*.tif) in QGIS 2.2.0 Valmeria. It is working but QGIS draws a black box around the georeferenced raster image. If i use the option set 0 transparent, not ...
3
votes
1answer
167 views

Expand raster extent and set expanded values using nearest neighbor sampling

I have run a hydrodynamic model which has given me a grid of surface elevations throughout a bay. I am trying to process the results in ArcMap (or QGIS if needed). My goal is to take the current grid ...
0
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0answers
66 views

How to set raster values to NULL?

how can I define values to null? I tried it with the processing reclassify tool but I always get an error log (cannot open the result shape...or something like that).
0
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1answer
50 views

Clipping several raster layers to the same exact size QGIS

I'm new to QGIS, sorry if this is a newbie question... I need to clip about 40 different raster layers from one vector layer (that has the boundaries of 4 neighboring countries) but I need them all to ...
1
vote
2answers
83 views

Road-construction (alignment) tools

Are there any tools available in any GIS environment for route alignment? To be specific, the tool should take a DEM and road-construction parameters -- distance and gradient, roadfill, drainage ...
0
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1answer
58 views

Point-sampling rasters using R? [duplicate]

I need to be able to sample many raster files (imported from GeoTIFFs) using a previously defined set of spatial points, using R. What's the best way to do this?
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0answers
206 views

Automating the production of GPS-compatible map tiles from georeferenced raster maps

I have a set of TIFF maps that I want to load onto Garmin GPS 62s units. The maximum size for each tile on the GPS is 3Mb and less than 1 million pixels. I manually produced one tile, following this ...
0
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0answers
34 views

How to raster vector- and shape-files correctly

does anybody know how to convert vector- and shape-files correctly? Doesn't work with tab Raster/convert/vector to shape files. The output always contains strange input-data (wrong and strange ...
2
votes
2answers
99 views

ArcGIS - Extract by Attibutes in Model Builder

I have a model which at one point uses the Extract by Attributes tool to produce a new raster with just the areas containing the maximum values of the first. I would think that the SQL expression ...
3
votes
2answers
1k views

Extract Raster from Raster using Polygon shapefile in R

I am new to R and using the raster package. I have a problem extracting polygons from an existing raster file. If I use extract(raster, poly_shape) function on the raster it always creates a list ...
2
votes
1answer
111 views

Why do layers appear in the wrong order in QGIS 2.2?

I have a problem with in which order my vector and raster layers appear in QGIS. I have raster that I want to be the background of my other layers (vector). I place the vector layers on top in the ...
0
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2answers
88 views

Clipping a raster file into the multiple shapefiles

I splitted the single shapefile into the multiple shape file based upon their attributes. Now I want to clip the raster file into the each splitted shape file. How can I do it at once? I am using a ...
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0answers
56 views

Error building pyramids/statistics on raster with arcpy

I am building a script to process rasters with the option of adding the extra step of building pyramids and statistics at the end. For some reason, it will not recognize inputs as legitimate raster ...
2
votes
2answers
97 views

Update raster value to reflect total number of points within cell- python

I have what should be a fairly simple task, but I can't seem to figure out how to do it. I have to do it in python/arcpy/gdal/whatever because I'm trying to automate this process for a hundred or so ...
3
votes
1answer
53 views

How to obtain the width and height of an image using arcpy

This Stack Overflow question shows how to obtain the pixel dimensions of an image using Python. Is it possible to find an image's height and width using arcpy and ArcGIS? arcpy.Describe would seem ...
0
votes
1answer
92 views

How to isolate certain raster values using raster calculator?

I have a one band grayscale image. It has values 0-63 within the band. I need to isolate some of those values. Is there a way to do this in the raster calculator? QGIS 2.2//Windows 7
0
votes
1answer
150 views

Gdal creating raster rotated wrong way

I have been trying to read in a stack of images for a timeseries and created an output raster that contains the max pixel values of the timeseries. The arrays were created using numpy img_stack = ...
1
vote
1answer
327 views

QGIS DEM (Terrain models) Mode Slope creates wrong data [duplicate]

I have a DEM raster file downloaded from the USGS site. The file can be downloaded here. I am trying to create a slope raster in percent with the DEM tool in QGIS. The GDAL command is the following: ...
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0answers
97 views

How to use the raster calculator in the processing modeler of QGIS

I am trying to create a easy way to do raster analysis by building a model for two way raster calculations. I have two raster layers that I want to combine into a single raster. For now I've done this ...
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0answers
102 views

Precision for an FGDB raster dataset?

I would like to know the precision for an ArcGIS raster stored within a file geodatabase (FGDBR format); I can't seem to find this information anywhere in their documentation (apologies if I have ...
1
vote
1answer
85 views

How to rename multiple rasters with modelbuilder

I have 101 raster images stacked inside a folder. The Rasters are of arcinfo grid type (*.asc) while having a long string name 'NW2D_T100_05_base_depthXXX.asc' where XXX ranges from 000 to 100. What ...
1
vote
1answer
55 views

How to deal with empty corners in raster when calculating fragmentation index

I have clipped buffer area around coordinate from one big raster (forest cover). Such created raster was loaded in R where PatchStat function (library SDMTools) gives fragmentation index. After ...
1
vote
2answers
44 views

Creating Many Uneven Buffers

Qgis 2.2, Windows 7 I am looking to create buffers around city lights (the raster). Currently, I have simple polygon buffers around the point layer (oecdminusa), but this is not accurately capturing ...
4
votes
2answers
186 views

Converting shapefile to raster: Character attributes

I've got a shapefile that I would like to convert into a raster, but the trick is that the attribute I want a raster version of is character data. I'm familiar with geoprocessing using GDAL (in the ...
3
votes
1answer
160 views

Getting Zonal Statistics of Overlapping Circles?

I have a Buildings (polygon) shp file and a DSM. what I wanted to do was to get the pixel values for all the vertices of those buildings, and find another pixel value just around those vertices (say ...
0
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0answers
58 views

Raster format similar to ECW

I need an alternative to the ECW format that we currently have for a new series of Ordnance Survey maps. The ECW format looks clearer and less pixelated than the new maps in Tif format (in QGIS). ...
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vote
0answers
59 views

Anyway to make Raster look like distinct Polygons

Is there any clever way to make a raster have a more clean vector look to it with straight polygon looking boundaries between classes when adding symbology to the data? Sure I could convert the ...
1
vote
0answers
46 views

Calculating Percent Overlap Between Distribution Maps

Hello there, I am currently trying to calculate the percent overlap (basically the total amount of overlap where these two species come into contact) between Lithobates catesbeiana (first image) ...
1
vote
1answer
88 views

Raster Attribute Table Where Each Pixel = 1 Row

In ArcGIS, is it possible to create a raster with an associated attribute table where each pixel is represented by a "row" in that table. I would like to specify unique attributes for each raster ...
2
votes
1answer
100 views

Cell Size of Raster Explained

I'm not quite understanding the cell size values that a given raster has. I been doing some kriging interpolation on some very dense point data and if I leave the cell size parameter blank, it's cell ...
2
votes
1answer
33 views

Polyline frequency to raster

I have some animal tracking data in the form of a polyline shapefile and want to convert this to a raster so that each pixel is given a value of 1 for every instance in which a line crosses it. I've ...
2
votes
2answers
115 views

raster standard deviation stretch python script

I am looking for ways of applying a permanent standard deviation stretch to rasters via python script. Are there any arcpy raster stretch functions? I was looking for a reference but could not find ...
4
votes
1answer
242 views

How to add tree height values to raster / vector data?

I am new to working with raster data and I am trying to teach myself a few things. I have what I think is a simple problem but I can't seem to figure this one out after a few hours of searching Arc ...
1
vote
1answer
63 views

Why do the raster band values have different values than the raster statistics?

I am working on a raster file (1 Band). According to the raster metadata, my minimum value is 0 and maximum is 7458. This seems to be confirmed by the Style options that return some category values ...
3
votes
2answers
58 views

How can I get my raster analysis to produce a larger extent in ArcGIS

Ok so the situation is as follows. I have an vector shapefile and within that area there are three points. I converted the points into raster and now I want to do a Euclidean distance analysis in ...
2
votes
1answer
118 views

Find maximum and minimum value in a list of raster

I trying to write a standardisation script that standardises each raster dataset in a list of rasters by the highest and lowest values found in the list of rasters. The standardisation code is as ...
4
votes
1answer
297 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 ...