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6

Yes, manual digitization is slow. There's a reason why scanning and raster-to-vector processing has replaced digitizing in major paper map conversion efforts. Twenty-five years ago, half of Esri's employees toiled at 4-hour shifts on digitizer boards or worked at QC tasks reviewing data collection. Now there may be a few large boards left, but they're ...


4

Why don't you digitalize the discrete points given in the map? The value beneath the point should be the source for the isolines. If you prefer the curves, take the lowest value found inside.


4

The v.split.length function from GRASS should do exactly what you want by splitting the line into equal segments defined by the user without the need for a point layer. Here's a simple example of a straight line (it also works on non-straight and multiple lines): I added a column to calculate its length using $length in the expression: Using the ...


3

It sounds you are after automatic raster to vector conversion and the extension to ArcGIS for Desktop that does that (as mentioned in a comment by @radouxju) is ArcScan: ArcScan provides tools that allow you to convert scanned images into vector-based feature layers. The process of converting raster data to vector features is known as vectorization. ...


3

Go to Settings - Options, digitizing tab. Tick "Suppress attribute form pop-up after feature creation".


3

The result of the interpolation that you digitized is represented in classes instead of continuous values. Therefore each color represent a interval of values, something like: < 100 100 to 250 250 to 500 > 500 (Note that the limits could be inclusive or exclusive) Now, if you plan to do some algebra analysis with it, classes and categories might not ...


2

You might like to have a look at this document, which shows an example of using the Polygonizer to make a geological map. http://confound.me.uk/maps/ppv4.pdf‎ After some recent problems, in my version of QGIS (2.3.0-Master, from Ubuntugis) the Polygonizer is now working again. Search for 'Polygonize' in the Processing Toolbox. N.


2

Finding the "right" projection is a rather time-consuming process. The best way would be to ask the map creator (if he still lives), but I guess this is not the answer you want. So take a look at available map projections, e.g. at http://www.radicalcartography.net/index.html?projectionref, and compare the shape of the degree grid with your example. At ...


2

3D is not (yet) implemented in QGIS, but you can store the height in an attribute table field and create a 3D output manually with ogr2ogr -z_field fieldname outside QGIS. See Is it possible to create 3D dxf with OGR? for an example. This is rather 2.5D, because all vertices of a line must have the same elevation (as contours have). In QGIS, you could use ...


1

There's a couple of ways of going about this. In both cases ensure you have set up snapping. Cut your hole (Egypt) as per the tutorial and you will get your original polygon with a hole where you want the new feature to be but note how, in creating the ring, it leaves the original outside edge alone (you need to digitize along the edge in this case ...


1

Scan the map to xxx format and add the map to ArcGIS (sounds like you have it in jpg already). Use the Georeferecning Tools to get the map in the correct location using ancillary data. A good time to set the projection. Create empty point, line, and polygon Feature Classes. Using the Editing Toolbar to digitize your features into the files Add required ...


1

ArcScan is meant to digitize drawings (typically scanned cadastral maps or the likes). In your case you want to classify an RGB image. With a true color image, you can use the image classification toolbar . You'll need to draw some sample polygons and use them for training a classifier. You need spatial analyst licence for that, and I would rather use an ...


1

As long as you 'drew' the lines from upstream to downstream in a consequent fashion, you can do this through the styling options. Right-click the shapefile layer, select Properties. Then select 'style' from the left hand side menu. Where you set the linestyle, on the top right you can choose a symbol line. Then you can select which symbol (I used the ...


1

@Mapperz suggested I configure my tablet not to response to double click. I tried doing this but the features were non-responsive. It seems that the Pen and Touch and default windows tablet features and services are taking over some of the Wacom Intuos functionality. After I turned of the Table PC Input Services and then Tablet PC Component Features and ...


1

You can snap a line to itself, but only after saving. My workaround is to digitize the line, but set the last point a bit offset to the first point, then save, and then move the last point to the first. As a consequnce, I start digitizing a new closed line with a point that is already created by another adjacent polygon if possible.



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