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

learn more… | top users | synonyms (1)

1
vote
0answers
28 views

How to OCR topographic maps

I have old topographic maps that i have scanned and converted into pdf in Actobat XI 11. I need this pdf to be text-searchable (not mere image). To do this i tried text recognition in acrobat but it ...
0
votes
0answers
60 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 ...
2
votes
2answers
143 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 ...
1
vote
0answers
63 views

Calculating vector area in QGIS

I have calculated a viewshed (ZVI) in OpenWind and opened the raster in QGIS I have then converted the raster to a vector When I open the attribute table there are 4682 rows (features) and there is ...
0
votes
0answers
84 views

How to collapse dual lines to centerline in QGIS?

I'm in the process making of semi-automatic feature extraction from printed map tool. The feature I need to extract was a line, but on the map it's obviously in a raster data model. So after Raster ...
1
vote
5answers
112 views

In what real-world examples do users still digitize features from a map?

Is digitizing of map features completely dead? For example, when and why do you still digitize features from a map? It can be heads digitizing up from a scanned paper map (or image, or whatever) or ...
0
votes
0answers
24 views

QGIS Export section from raster to AutoCAD

QGIS Windows 7 I have a raster which displays the flood depth over my site. What i would like to do export to AutoCAD an outline (maybe as a polygon or line) of the sections of the raster which are ...
4
votes
2answers
233 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 python gdal library? I have tried with gdal_polygonize.py of gdal utilities in command line and it worked excellent. ...
2
votes
1answer
57 views

Incorrect vectorization from a raster in ArcGis (ArcScan)

I am trying to make a vectorization to get lines from a raster image using arcscan. I saw some users making it but using easier images with more visible lines but is not working with my image. could ...
1
vote
0answers
111 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 methods ...
1
vote
1answer
52 views

Preserve polygon boundaries when vectorizing a raster according to a polygon vector

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 ...
1
vote
0answers
297 views

How to automatically vectorize data from WMS?

I am facing a problem, when I have a historic map in WMS layer and I need to get buildings from this map (approx. 2000) to vector layer fo further analysis. Is there any workflow how to ...
2
votes
1answer
86 views

Smooth out lines in QGIS

I have taken a raster image and coverted it to a vector file. It is an OS map which shows field boundaries etc. As the vector file has been created from the pixelated raster file the lines are ...
2
votes
0answers
291 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 ...
6
votes
2answers
578 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: ...
1
vote
0answers
67 views

When digitizing, polygons are inverted

I need to use QGIS to digitize my images. My images are scanning electron microscope (SEM) images of rocks. I am interested in analyzing the pore space in the images. Here is the steps I follow: I ...
3
votes
3answers
922 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
1answer
2k views

How to convert 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 ...
3
votes
4answers
2k 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 ...
6
votes
3answers
829 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 ...
5
votes
1answer
182 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) ...
9
votes
4answers
1k 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 ...
6
votes
1answer
475 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, ...
9
votes
2answers
2k 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 ...
5
votes
5answers
1k 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) ...
2
votes
1answer
1k 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 ...
5
votes
1answer
2k 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: ...
2
votes
2answers
198 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 ...
3
votes
2answers
1k 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 cant vectorize the classes to get polygones for every class. Whats the best ...
4
votes
1answer
894 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 ...
2
votes
4answers
8k 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 ...
7
votes
1answer
189 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 ...
7
votes
2answers
2k 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 ...
19
votes
6answers
11k 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 ...