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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

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

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

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

No. You need a Mapbox Commercial Satellite licence. https://www.mapbox.com/tos/#[YmtIyw] You may trace Mapbox-hosted imagery in order to produce derivative vector datasets for non-commercial purposes, and for OpenStreetMap. If you wish to produce derivative vector datasets from imagery for commercial purposes, you must buy a Mapbox Commercial Satellite ...


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

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

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

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 ...


2

The easiest way would be the following: enable snappig on the line layer that you are using to digitize digitize the line, but finish your sketch before you close it digitize another line, start digitizing at the end of the previously digitized line (using snapping), finish the line at the start of the previously finished line (using snapping) now select ...


2

Not sure what version of QGIS you are using. I have 2.8.2-Wien. This has advanced digitising tools that allow creation of circles by selection of two points, selection of three points, selection of centre and input radius and selection of a centre and a point. Just ensure that you have the CADDigitize and CadTools plugins loaded to access some good ...


2

You can also use the plugin 'Rectangles Ovals Digitizing' for creating rectangles, circles and ovals. Side note: Just read that the new geometry engine of the coming QGIS 2.10 supports curved geometry types. I am not sure how this would apply for circles.


2

I'm not sure how well this will work without trying on your specific raster, but a few pointers. I assume from your image you used Threshold in GIMP to give you a binary raster (inside field/outside field) Removing noise You can use GDAL Sieve to remove the 'salt and pepper' noise - those little holes within the fields. You can do this from QGIS (Raster ...


2

Steven already shared a very good walk-through! I just want to add that you could also use the QGIS LecoS plugin (requires active numpy/scipy installation within your QGIS path) for this purpose. Especially for raster basic cleaning and edge extraction purposes. LecoS has a so-called landscape modifier since some time, which applies scipy's erosion ...


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.


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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 is a company here in town that a large portion of their business is manually digitizing plan and profile sheets for gas and oil companies. Presumably because the CAD files aren't available or it would be just as much work or more to translate them into the desired GIS data structure. I and others I know of frequently digitize field notes and sketches ...


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.



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