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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 ...


5

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 ...


4

Ok, so after a frustrating week, I've actually found a few new things out about QGis. Cheifly, I was still using version 2.2.0 when I posted this question, I've since upgraded to 2.8.1. What follows is a little bit of a tutorial for those folks who might be looking to tackle the same problem. The solution for me was a plug-in called cadinput by Oliver ...


3

You can clean up the scan in Gimp first and make processing a lot easier: Use the 'select by colour' tool and select the map background, adjusting the threshold to give a nice clean selection. Invert the selection, so the lines and points are now selected. Now 'shrink' the selection down Select > Shrink... by enough pixels so that just you points ...


3

I have had similar issues. One approach I have done is to use the CadInput tool. This tool allows you to draw vectors based on distances, angles, etc. which ensures that when you enter in a new vector, they snap to the point you want. It works with the snapping tolerance that is native within QGIS. https://vimeo.com/85052231


3

Without any scripting, the easiest is probably by creating virtual fields (available from QGIS 2.6). You will need to create a project file (.prj) for this via the toolbar Project > Save As... Then for your point layer, open your Attribute Table > Field Calculator (see image for options selected and expression): Repeat for a "Northing" column. These ...


3

You can use the Freehand editing plugin (not to be confused with the trace edit tool). Get this by installing it through the plugins menu option. Another option would be to use edge detection in the Processing toolbox (Have a look at tools in GRASS and Orfeo. SAGA maybe has one too I forget). The downside of this is that it will detect all edges. What I ...


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".


2

Not being able to save the geometry due to a read only attribute windows with a disabled ok button is an issue in QGIS 2.4. The freehand plugin works fine in QGIS 2.6.0 and QGIS 2.8.1.


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 ...


2

Following the request "Gene, Can you expand a little" for geological maps,here are the explanations using Aprèn a interpretar un mapa geològic of the Institut Geològic de Catalunya: 1) First, geological field work : Field work figures from Field work 2) Laboratory work: geological map construction, cross sections, etc. (paper, GIS,look at 4)): Cabinet ...


2

With ArcGIS for Desktop Advanced, you could Convert all depression lines vertices to points (with Feature Vertices to Points) Convert all vertices back to lines (with Points to Line, with the Close Line option checked) Revert the direction of all lines (with Flip Line).


2

Alternatively, you can use the Vector -> Geometry Tools > Add Geometry Columns, and execute both X/Lon, Y/Lat calculations at once


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

A similar function has been introduced recently It requires the possible values to be grouped on the related layer and is slightly more involved in setup. If you have a layer Plots Name class (foreign key to Classes:pk) And a layer Classes pk Type [Agriculture/Forest] Plant [Pines/Olives/Corn/Wheat] You will need to add a new relation in Project ...


1

First, you should confirm that the edited layer is visible(clicked in layers section).You can also check the color set by default by QGIS for new digitized features. If the two are ok and the issue persists you can first digitize the features then edit their attributes later. Hope this helps !!


1

You can achieve your results with a combination of tools and plugins. It's not perfect but it will work Use "Rectangles Ovals Digitizing" plugin to create rectangles. Use "Advanced Digitizing" tools to rotate the rectangles. See Step 29 onwards of this tutorial for the exact workflow. Use "Orthogonal Digitizing" tool from CAD Tools plugin to draw polygons ...


1

Here would be a way to add a new feature to a polygon vector: # reference your layer, such as the active layer lyr = iface.activeLayer() # get the vertexes of your new geometry and add them to a list coordinatePairs = [] coordinatePairs.append(QgsPoint(-80.23, -3.28)) coordinatePairs.append(QgsPoint(-65.58, -4.21)) coordinatePairs.append(QgsPoint(-65.87, ...


1

Thanks very much for pointing me towards CadInput. This got me on a continued hunt and I ended up using another plugin called CADDigitize [ https://hub.qgis.org/projects/caddigitize ]. I was originally confused because this plugin does not provide visual feedback of the snapping. But if you hold down the control key, it will snap the actual nodes when you ...


1

If GISGe's solution works, I'd go for it. Nevertheless, if you still need a solution to remove the holes from polygons, you can just run the union tool and unselect the "gaps allowed" checkbox.


1

As mentioned by Mapperz historical paper maps/drawings still get digitized. Three examples include the digitizing of old coal mine plans, the digitizing of land parcels, and digitizing building plans. With the parcel data we were using Esri's parcel fabric so rather than digitize we used the survey measurements on the plan and then used least squares ...


1

For work related projects, where GIS data and layers are seldom available, I extract the data from maps and official documents that were published. As gyoung1986 mentioned, these data usually comprise of infrastructure, but I also found myself digitizing borders and other political boundaries, as well as the incorporated areas of interest, from PDF maps.


1

I use this method when I am trying to draw existing gathering systems and transmission pipeline routes that are given to us by clients when they do not or are not willing to give us their .shp files. I can get maps of these lines on the internet of the pipeline is large enough then use the georeferencing tool to lay them into Arc.


1

I have a side project at the moment that looks at the historical routes of horse-driven and electric trams in New Zealand cities. I have some old maps of these that I have scanned and georeferenced. I will have to heads-up digitise these, as no autovectorisation proceedure seems to work—the pictures are all monochrome, labels and text overlap, routes I want ...


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

I found the solution.... The parameter in Options|Digitizing|Snapping "Search radius for vertex edits" has to be non zero... With zero value Node tool gives the reported message.


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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

Try ticking the checkbox on for Settings -> Option -> Digitizing -> "Suppress Attribute Form Popup after feature creation."


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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 ...



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