Questions tagged [vectorization]

The conversion of raster data (an array of cell values) to vector data (a series of points, lines, and polygons).

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27
votes
5answers
28k views

How to convert image of map into vector format?

What is the best way of converting a gif of a map into a vector format, such as a shapefile? The only relevant parts that I am interested in are the outline of the island so I realize some manual ...
12
votes
2answers
5k views

How to smooth large vector polygons from Raster

I have a landuse classification raster file (6 classes) of a large area. But I need it in vector polygons so I vectorised it. No problem so far, but the result is - of course - that every pixel is ...
10
votes
5answers
5k views

How to generalize and vectorize a LandUseClassification raster file?

I want to vectorize that rasterfile with its 6 landuse classes. The classification is very noisy and have to be generalized before. The result should be a polygone vector file. I use SAGA, (GRASS) ...
10
votes
2answers
430 views

Tools for importing historical maps into modern GIS systems?

What tools exist to derive geometries for use with modern GIS systems from older scanned maps? I am referring more to libraries that generate actual data rather than present an interface for ...
10
votes
4answers
4k views

How to “clean” and vectorize a raster map?

I'd like to make use of a geological map as shown in the example below, which is only a pretty small and downsized part of the map, so editing/redrawing doesn't seem to make sense in the end. My idea ...
9
votes
2answers
4k views

Spatial statistics tools : clustering analysis on raster data

I've an apparently simple problem, but i can't find a clear methodology to use. I'm tasked to delimit "urban areas" by vector convex polygons, using the Gridded Population of the World dataset from ...
9
votes
2answers
1k views

Scriptable alternative to ArcScan (particularly vectorising lines within tolerances)?

Sadly the answer to Can you access ArcScan from a python script? suggests that it is not possible to script ArcScan from within a python script. Therefore, does anyone know of any alternatives to ...
8
votes
2answers
283 views

Estimating resolution of vector data?

I got an old vector dataset with polygons covering a continent. The data was first published on paper at scale 1:5 000 000 and was later digitalized. I don't have the original data and no information ...
7
votes
2answers
3k views

Convert points to lines with Python GDAL

I have a dictionary with points. The points are derived from a raster (see image below). The points are not sorted and are not in order. The dictionary looks for example like this: pointDict = {0: (...
7
votes
1answer
1k views

Free implementation of Polynomial Approximation with Exponential Kernel (PAEK) algorithm

I need a Free (i.e. Open Source) implementation of the Polynomial Approximation with Exponential Kernel (PAEK) algorithm, preferably in C, C++, Python, Julia or R. The algorithm is one of the ...
7
votes
2answers
2k views

Converting raster to vector by generating center lines?

I have a binary raster containing boundary pixels with the value 1 (white) and no-boundary pixels with the value 0 (black): I would like to vectorize the raster by keeping one center line trough the ...
7
votes
3answers
2k views

Raster to vector conversion

I have a bunch of raster maps from a general plan of a city. Examples: Areas reserved for federal, regional and municipal buildings Special land use zones Zoning Risks of occurrence of emergencies ...
7
votes
2answers
8k views

Extracting road and building features from raster data using ArcGIS Desktop?

I work with raster data and my task is to digitize a big image. This consumes much time just for digitizing roads and buildings! I'm looking for tools to simplify working on raster data to digitize ...
7
votes
1answer
5k views

How to clip raster and split by individual polygons in QGIS

I have two layers. The first one is a vector layer with 6 polygons. The other one is a raster layer. I need to extract specific surface information for my polygons (average slope value). The ...
7
votes
1answer
5k views

Selecting and extracting data from TIFF files

I have some tiff files (2 for example) and a shapefile. The real format of the tiff files is geoTiff. I want to get the points inside the shape boundary. Each point should have 4 parameters: geom(...
7
votes
1answer
226 views

View data of a particular year in Google Earth

For my region in India, Google Earth tiles belong to different years, 2003 - 2010. I don't mean GE's historical view feature but the imagery updates for different areas my region. I classify Landsat ...
6
votes
1answer
662 views

Extracting the pixelwise proportion of classes of a finer raster in a coarser one

I have two rasters, one has a 1 km resolution. The other has a spatial resolution of 30 m. This latter pixelwise is a classification. I want to overlay the 1 km raster on the classification raster and ...
6
votes
1answer
804 views

Generalize large polygon-file

I have a large polygone file with landuse information (6 classes). Its vectorised from a raster classification so the polygons are all angular. Any of my tries to generalize with v.generalize (sneaks, ...
5
votes
2answers
4k views

How to convert float raster to vector with python GDAL

I have float raster and now I want to convert it to vector. How is it possible with the Python GDAL library? I have tried with gdal_polygonize.py of GDAL utilities on the command line and it worked ...
5
votes
1answer
241 views

Calc bottomline of valleys

Which way do I calculate bottomlines of valleys or even more preceise: which way do I "find" valleys (for example suggested tectonic faults). Sample below shows a height profile (profile from line) ...
4
votes
1answer
2k views

Convert a raster to GeoJSON polygons in PostGIS

I'm trying to convert a raster to a polygon and export it from PostGIS as GeoJSON. Specifically I want each pixel to be a polygon with associated the raster value. PostGIS seems to have a few ...
4
votes
1answer
2k views

Convert image in KMZ to polygon

I have a KMZ file that contains several image overlays (RF coverage plots). I would like to convert the image overlays to polygons to decrease loading time in Google Maps. Currently I'm tracing a ...
4
votes
2answers
710 views

Digitizing raster in ArcGIS Desktop?

I have the raster below which I want to convert to a set of vector lines: As you can see, there are small breaks in the lines and some bits are double-width. I want to be able to reliably import ...
4
votes
0answers
148 views

Arcpy code only works when run in two chunks, not as one piece [closed]

I have a weird thing happening with my script. When I copy/paste it into the python cmd line within ArcMap, I get error messages. However, if I run the first part, then copy in the very last line by ...
3
votes
4answers
3k views

Converting Esri ASCII raster to Shapefile for CartoDB?

I have an ArcGIS grid ascii file (Ramankutty Cropland at 5 minute resolution) that begins as follows: ncols 4320 nrows 2160 xllcorner -180 yllcorner -90 cellsize 0....
3
votes
2answers
473 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 ...
3
votes
2answers
1k views

Convert raster to a CSV values and lat long based on raster value in QGIS

I am looking to convert a raster into a csv file (or tab delimited) based on values in the raster (Value > 0). The csv would have three values, latitude of center of cell, longitude of center of cell,...
3
votes
4answers
10k views

Avoiding Raster to Shapefile (Polygon) errors 000863 and 000308?

Have you experienced converting a polygon from raster? The raster dataset is a satellite image created from zonal statistics? The problem is when I was converting the raster to polygon errors came out ...
3
votes
2answers
1k views

Creating point shapefile from GeoTIFF using GDAL/OGR?

I have a 0.05 deg global maps (~8000 files) in GeoTiff format. It's a kind of a mask containig "1" and "0". I need to create a point shapefile for each raster with points located over "1" values of ...
3
votes
1answer
2k views

Convert 3-band raster imagery to distinct vector zones in ArcGIS

So much like the title says I would like to convert a 3-band infrared image TIF file of vegetation into distinct vector feature zones using ArcGIS. I'm guessing the only way to do this is with ...
3
votes
2answers
3k views

How to vectorize a Raster-Classification? (QGIS, GRASS)

I classified my raster-DHM into elevation levels using colormap. Its not a "real" classification, just a colormap. So I can't vectorize the classes to get polygons for every class. What's the best ...
3
votes
1answer
29 views

Finding external boundary of bunch of vectors (using R libraries)

I have vectorized raster as in the image. This is actually 1419 polygons in SpatialPolygons class object. I'm looking for a method which would allow me to extract the one most external polygon (...
3
votes
3answers
5k views

How to make mapable geo data from a solid jpg/png

I have a bunch of hardiness zones, as you can see here: http://mangoly.herokuapp.com/workroom/googlemaps/zones/ They are solid colored PNG images. I know the geo coordinates of the bottom left hand ...
3
votes
0answers
61 views

Extracting GeoTIFF colours and adding to equal geometry shapefile

I have the following map in .png-format that I would like to replicate, but I cannot obtain the original data. The map shows the current water supply vulnerability for local municipalities in South ...
3
votes
0answers
602 views

Seeking QGIS plugin with functions like ArcScan?

Is there a QGIS plugin which does raster scanning, like ArcScan. Typical QGIS Vectorization returns very bad outputs that have thousands of 'islands'. I require a clean and efficient vectorization ...
3
votes
0answers
770 views

Watershed Segmentation SAGA-GIS

I'm trying to segment a topographic map to vectorize it. I'm using the watershed algorithm of SAGA-GIS. It's working fine with polygons, but with roads or contour lines is not working properly. Here ...
2
votes
1answer
7k views

Converting jpg file to shapefile? [duplicate]

I am developing a GIS application like this: By now my steps are: I have got a jpg file, 5040 x 8179 dimension. In this map, the roads, rivers, towns etc. are marked. I am using .Net to develop and ...
2
votes
3answers
237 views

Grass GIS: ArcGIS' “Raster to polygon” equivalent

I've got a small clipped extent of a LANDSAT image and I need to have the single pixels as polygons in order to tell the overlap proportions of overlaying polygons. In ArcGIS I used "Raster to polygon"...
2
votes
2answers
538 views

Vectorizing from raster image with discontinuities or breaks in polygons?

I am new to this site, so I have explained much as i don't know proper terminology. I am using ArcGIS Desktop 9.3, in which I am trying to create vector polygon shapefile. But the raster image i have ...
2
votes
1answer
153 views

Preserving polygon boundaries when vectorizing raster according to polygon vector? [closed]

I have a raster which I clip by some polygons and then convert to polygon. I would like to obtain the same number of polygons in both my vector files. The problem is that some areas in the vector ...
2
votes
2answers
329 views

River drain: r.watershed to vector is not working

I want to vertorize the result of r.watershed (accumulation). After using r.to.vect I got the message that I have to use r.thin before. So I did, but the message comes again and again. What I am ...
2
votes
1answer
4k views

Converting DEM to Floating Point Raster (FLT) using QGIS?

I am looking to convert a .DEM exported from AutoCad to a floating point raster file type (.FLT) utilizing QGIS to implement in HEC-RAS Mapper. This is accomplished easily in Arc using the Raster>...
2
votes
2answers
1k views

Converting classified raster map back into vector classes using QGIS?

I have this map (have whole country, this is just a sample, original map also contains color symbology for the value classes) and need to attach the values from it to points. I have no problem to ...
2
votes
1answer
26 views

How to merge pixel values to the nearest maximum value based on area in a classified raster?

We have a raster image with 9 discrete values. Generated the image using SAGA's Terrain Analysis -> Morphometry -> TPI classification technique. Now, like to merge pixels which occupy certain area (...
2
votes
1answer
173 views

Raster conversion to vector with multiple fields retained

I have a raster which I have successfully polygonised using: raster / conversion / polygonise (raster to vector). However, my raster has multiple fields (data columns) within it and I've only been ...
2
votes
2answers
470 views

Extracting coastline as vector from landsat 8 imagery?

I am trying to detect some sea level rise/fall for a specific region, from Landsat imagery. I went through the recommended methods of identifying water/land (MNDWI, AWEI, Bandratio 5/2, etc.). Now ...
2
votes
1answer
822 views

Under what situation do we use Rasterisation or Vectorisation?

As mention in the title, Rasterisation is the conversion of vector maps to raster grid. While Vectorisation is the conversion of raster grids to vector maps but under what situation would we use these?...
2
votes
1answer
400 views

Jpg Photo to point layer

How do I open a Geotag (.jpg) Photo in ArcGIS 9.3 (or photo to point)? In 10 and above versions it shows an ArcPhoto option in Data Management tools, but not in Arcgis 9.3.
2
votes
1answer
392 views

Smooth vectorized outlines in QGIS

I have taken a raster image and coverted it to a vector file. It is an Ordnance Survey map which shows field boundaries etc. As the vector file has been created from the pixelated raster file the ...
2
votes
0answers
59 views

Converting historic map data (raster) into polygon format? [closed]

How do I convert historical buildings from map data (raster) into a polygon format? The historic maps that I am referencing are the Sanborn Fire Insurance Maps. Here is the link to an example in case ...