Questions tagged [raster-conversion]

Raster conversion between raster formats. Do NOT use for raster to vector conversion (and vice versa) - for that use vectorizing (and rasterizing)

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8
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1answer
5k views

QGis Save Raster as Rendered Image

In QGIS 1.9.0 Master, when you right click on a raster in the Layers Panel and select "Save As", you can select the output mode to be "Raw Data" or "Renedered Image". When selecting the Rendered ...
6
votes
1answer
6k views

How to convert raster to polyline in QGIS?

How can I convert raster (stream segments result of a watershed analysis) to vector polylines, preferably shapefile. In ArcGIS this is easily acomplished with the Raster to Polyline tool. I only see ...
5
votes
1answer
3k views

Create conditional to check if raster has value

I have a problem with this code: ac = ExtractByMask(raster, "area.shp") arcpy.RasterToPoint_conversion(ac, "point.shp", "VALUE") The problem is that sometimes the raster has no value. (It's a flow ...
2
votes
2answers
4k views

Convert geojson to png

I want to transform a geojson in a .png image. Do you have any lib/tool/tip to accomplish this task in Java? I googled a lot but no luck.
2
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2answers
5k views

Exporting GRID to TIFF keeping (classified) symbology using ArcGIS for Desktop?

I want to export an esri grid-raster into a *.tiff without losing the symbology I created for the grid (the symbology is classified). No matter how I try to solve it I get a stretched symbology in a ...
3
votes
1answer
1k views

Appropriate pixel size when converting vector to raster

I am converting vector polygons into raster datasets. Is there a standard calculation for converting the scale of the vector into an appropriate pixel size (e.g. 25 metres)? My vector has been ...
5
votes
1answer
1k views

Polygonizing a raster yields lots of little squares?

I have a pdf with the area of a county that I want to separate into multiple shapefiles (polygons) based on color. As shown in the first picture there are 4 colors so I would need to separate based ...
4
votes
2answers
11k views

Flattening multi-band raster to single-band raster in ArcMap?

I need to convert a multi-band PNG image into a single-band raster, for analysis and visualisation. How can I do this in ArcGIS Desktop 10.2?
4
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2answers
5k views

Converting *.tif file into headerless (flat) binary file?

I am using NDVI files (value range -1 to +1) created from Landsat CDR images to produce a timeseries in TIMESAT software. My .tif file has following characteristics. File type TIFF,Data Type ...
1
vote
1answer
602 views

Generating a DEM and DSM from correct LiDAR point classification

I have downloaded classified LAS data from http://lidar.unh.edu/map/ I am trying to generate accurate DEM and DSM for further analysis. I created a LAS dataset with a projected CRS of ...
1
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2answers
3k views

Convert Raster Resolution in arcGIS

I have to analyze 8 raster layers, 5 of them are 0.5 degree resolution and the other three are 0.05 degree resolution. Firstly, should I resample the 5 to finer resolution (0.05 degree) and if ...
7
votes
2answers
342 views

What resampling method is used in the raster 'Save as…' dialog?

I received a raster that was resampled using the Save as dialog in QGIS. Now I need to describe the resampling process in a report. But I could not figure out the method used in the resampling. Is it ...
8
votes
2answers
10k views

How to convert .geotiff --> .tiff?

How to convert .geotiff files to .tiff files (ordinary plain images)? Basically, I have cropped the image to a rectangle of interest and knowing its left-lower location and having chosen the pixel ...
5
votes
1answer
4k views

Exporting 16 bit single-band to 8 bit in SAGA/QGIS

Everytime with every function (e.g convert data storage type or gdal-translat -ot Byte) the output is a completely white map with a black border. only the "save as" export works, but the TIFF also ...
5
votes
0answers
707 views

Error running r.thin in QGIS

I get the following error when running r.thin: Traceback (most recent call last): File "C:/PROGRA~4/QGIS3/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Algorithm.py", line 395, in ...
4
votes
1answer
2k views

QGIS 2.2 Raster Merge losing color data

I'm trying to merge a couple of GeoTiff maps using Raster > Miscellaneous > Merge but the merge is only coming out in grayscale. The geotifs are using palettes color. How do I get the merge to keep ...
3
votes
1answer
2k views

Converting GMT grid to ArcGIS readable format?

I am trying to convert a GMT grid data into a format that is readable in ArcGIS. I have already attempted to load the data into GRASS and use GDAL translate to convert into a tif with unwanted results....
1
vote
2answers
3k views

Python/GDAL--Handling Big Rasters and avoid MemoryErrors?

I am using python 2.7.10. I am trying to read a big Raster with gdal and numpy array. But it show In MemoreErrors when i use this: band. ReadAsArray() Note: this error occurs when input raster is ...
3
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0answers
2k views

Converting raster file to vector in QGIS takes long time [closed]

I am a new user of QGIS, and I am trying to convert a .tif file in a vector. To do that I have used the "Raster conversion" option, but it is taking a long time. I am waiting 20 minutes for ...
3
votes
2answers
753 views

Conversion of OSM building to elevation raster

I have a roof as an OSM building, which I need to convert to an elevation raster to be used for QGIS calculation, with a raster resolution of 9pts/sqm. Typical OSM building would be: http://city....
3
votes
1answer
718 views

Python: Convert DEM to 3D array organized as [lat, long, elevation]

I'm trying to convert a .tiff DEM to a numpy array using python. Ideally the array will store latitude, longitude (or some coordinate alternative), elevation). I'm using Gdal but currently it only ...
3
votes
1answer
484 views

List of vector to one raster in PostGIS

I need to rasterize a part of OSM map by coordinates. I found rather good algorithm, but can’t finish it. I have problems in STEP 3. I described all algorithm here – may be someone have the same task....
2
votes
1answer
528 views

QGIS export png with accurate hex color values

I have a 32 bit TIFF raster layer in QGIS with one band of integer values between 49 and 72 with some no data values. I'd like to end up with an 8 bit PNG image with matching pixel values. I don't ...
1
vote
2answers
671 views

How to reduce Polygon to Raster (Conversion) bit depth?

I have a polygon featureclass that I am trying to convert to raster format at a low bit depth (i.e. <8 bit unsigned). The FC contains 50,000 polygons which have five values: 1,3,5,7,9. I have set ...
1
vote
2answers
3k views

Can QGIS2 / GDAL convert to .ECW without corruption?

I have qgis 2.0.1 and it can read *.ecw files that I download. However, when I convert say a *.jpg or *.tiff to *.ecw the output is corrupt. Has anyone seen this problem?
1
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0answers
2k views

Creating a contour raster from contour lines shapefile [duplicate]

I'm trying to create a 3D view in Qgis 3.0 for the first time. It's asking for a raster file from which to calculate elevations. All I have for elevation data is a shapefile of contours (as lines). I'...
1
vote
1answer
767 views

Rounding raster pixel values to one decimal place in QGIS [duplicate]

I have single band raster whose values somehow were set to something like 1.399999999 instead of 1.4, 1.29999999999 instead of 1.3 (I'm not sure about the number of 9's there.), 1.2000047683 instead ...
0
votes
2answers
238 views

Low resolution raster conversions to vector yielding millions of single pixel polygons. Trying to merge all directly adjacent polygons

I'm trying to scan plain pdf maps containing color-coded geographic regions and convert them into undifferentiated (I don't actually need them to contain any attribute data) overlays. My workflow is ...
0
votes
0answers
267 views

GDAL conversion to Terragen outputs file full of zeros?

I recently learned some gdal command line syntax in my attempt to convert some geotiff files to the Terragen format. During my first attempt I noticed a message about nodata values: gdalwarp -of ...
0
votes
4answers
3k views

Clipping raster with vector layer using MapInfo?

With MapInfo 12, i would like cut my raster layer .tab with one of my vector layer. How to do this basic task with MapInfo? Is it possible with mapinfo to convert .tab raster table toward any ...