Questions tagged [digitizing]

The process of converting features on a map or image (either hardcopy or digital) to vector-based data in digital format.

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13
votes
4answers
17k views

Digitizing raster automatically? [closed]

I have a raster (.sid extension) file. I want to digitize roads automatically in ArcMap, QGIS, etc. Digitizing by hand would be too time consuming. How can I do this ?
8
votes
6answers
4k views

How to Digitize Free Satellite Imagery in QGIS - Alignment issues with Openlayers Plugin

I am trying to digitize OpenLayers data (such as Google satellite imagery) with no success. Whenever I try to move or zoom the canvas the vector layer I digitized loses the position relative to the ...
26
votes
7answers
32k views

How to create polygons with straight lines and right angles in QGIS?

When creating a polygon, how do I do it so that the lines are straight (90, 0 degrees, etc.) and when I create corners they can be right angles? For instance, how do I create a perfect square or ...
2
votes
2answers
3k views

How to go with…somewhat complex geological maps in QGIS?

Just a follow-up to this question QGIS: Line to polygon conversion. Not sure do i have to continue there itself... We are currently digitizing a geological map...which has 36 features in total. Some ...
4
votes
3answers
1k views

“add feature” tool QGIS 2.0 - polygon fill blocks view of what I want to digitize

How can I change the settings on the vector "add feature" tool so the tool fill doesn't block my view of what I want to digitize? This problem popped up after I upgraded to QGIS 2.0 QGIS 2.0 Macbook ...
32
votes
2answers
56k views

Enabling “Snapping” in QGIS while drawing polygons?

I tried to draw polygons in QGIS 1.7.0 and somehow I can't find or failed to find the "Snapping" option. I'm used to ArcGIS 10.0 where you have some snapping options, like placing points of polygons ...
2
votes
1answer
71 views

Fill attribute-table on feature-creation based on intersection with other layer

I am digitising line-features based on WGS-84 point-coordinates from a PDF which cannot be copied from. The final line layer should contain lines which each connect two points and have the following ...
9
votes
1answer
4k views

How to split a line into a specific number of parts?

I've seen a lot of questions involving splitting a line with the help of a point layer. I want to split a line in fractions of its length. For example, I have a line 400 meters long, I want to split ...
3
votes
3answers
3k views

“Node tool: could not snap to a segment on the current layer” message

I have a strange issue. Editing a layer with node tool I get always the following message: "Node tool: could not snap to a segment on the current layer." This error happens to me even with a fresh ...
10
votes
2answers
9k views

How to digitize building footprints with orthogonal edges?

Using QGIS, I am trying to digitize an old raster map, and because I ultimately want to load these 2d layers into sketch-up to turn into 3D models, I need everything to be square. Here's a sample of ...
7
votes
1answer
7k views

Is there a QGIS bezier curve tool?

I'm a recent convert to QGIS but have been confused about the lack of support for drawing curved shapefiles, especially when Arc has almost too many. A lot of the work that our consultancy do is based ...
4
votes
2answers
1k views

Snapping multiple nodes of a polygon to the nodes of a line?

I am working with vector polygons that have derived from hand drawn areas from when mapping was carried out with tracing paper over paper maps. Therefore many of the polygons don't exactly line up to ...
2
votes
1answer
272 views

Line feature reshape tool reshapes unselected lines

I have QGIS 2.18.18 installed in my PC. I need to reshape large number of roads/tracks to match with Imagery. QGIS Reshape tool reshapes roads that are not even selected. Any suggestion? Below are ...
1
vote
1answer
4k views

How to indicate flow of a watershed feature?

While tracing and digitizing rivers, streams, rivulets, etc., is it possible to indicate the direction/flow in the shapefile on QGIS? I'd like to avoid using map labels. Ideally, when done tracing, I ...
5
votes
4answers
5k views

Looking for an efficient way of digitizing building footprints using orthophotos and ArcGIS 10

In the past I've used PCI Geomatica to do something similar using the softwares classification functionality. Are there some tools/tricks in ArcGIS that will partially automate the process. I remember ...
6
votes
2answers
9k views

snapping polygons and lines [duplicate]

I recently downloaded QGIS on a Mac OSX 10.7.4 (lion) and purchased a master map shape file, of a particular area. I am trying to divide it into polygons following features on the master map vector ...
3
votes
4answers
5k views

Figuring out map scale when you know the spatial resolution of a Satellite Image?

I'm interested in figuring out how map scale and satellite pixel size (spatial resolution) are related. For example the TM or ETM+ has roughly 30m ground resolution, then, what could be the finest ...
3
votes
0answers
349 views

CadTools plugin functionality in QGIS 3 beyond Advanced Digitising Panel?

I've recently migrated to QGIS 3.6.0, and I've realised that the wonderful CadTools plugin is not compatible with QGIS 3. I tried to use the Advanced Digitising Panel, but it's cumbersome and not ...
5
votes
2answers
1k views

How to digitize rectangles with snapping in QGIS?

Trying to digitize a floor plan for a building (just need polygons for each room) in QGIS (shapefile layer). I started just trying to draw the features, but want to align polygons so that there is no ...
2
votes
2answers
662 views

How to automatically convert dots on paper maps to vector points?

I have several paper maps with dots that I need to convert to vector points. I was hoping to get some suggestions on how to accomplish this without recreating each and every point by hand. I know ...
8
votes
1answer
2k views

Is there a way to automatically snap loose points of lines to close by vertices with Quantum GIS?

I have a vector layer of lines that were drawn with the snapping option off. I need to have them snapped but, there are hundreds of lines. Is there any solution to do this automatically or semi-...
4
votes
1answer
3k views

OpenLayers 3: Change drawing style, but keep style of previously drawn features

I created a vector and a drawing interaction: // Create feature collection and vector var featureCollection = new ol.Collection(); var vectorSource = new ol.source.Vector({ features: ...
4
votes
1answer
847 views

Create rectangle by entering width & height numerically in QGIS?

I need a quick way to create rectangles with set with & height in meters. Is there a straightforward way to do this? I am well aware that there are a number of ways to achieve this, but all that I ...
3
votes
2answers
293 views

I am unable to draw a shape layer

When I add a new shape layer or want to edit an existing one, nothing is happening. I even don't see the dots where I'm clicking. Maybe the problem is I deleted some layers (by opening the .qgs as a ...
3
votes
1answer
288 views

Splitting rectangles into a desired number of parts in QGIS

I'm working on a project using QGIS and there is a process that I'd like to try to automate. I'm working with the "rectangles,ovals digitizing tool" plug-in to make perfect rectangles. The next step ...
3
votes
1answer
987 views

How to find the projection of an image?

Instead of georeferencing the image and deforming it, I'm trying to find the projection used by the author of the image. I've got tens of these distribution maps to digitize. The idea is to avoid ...
3
votes
2answers
2k views

Resuming (continuing) digitizing polygon feature from any vertex in ArcMap?

When I digitize in ArcMap with a Wacom tablet and a pen I often accidentally double click and finish my sketch. More often then not the accidentally finished sketch crosses itself. I would like to ...
3
votes
0answers
318 views

How to digitize 90 degree angles? [duplicate]

Possible Duplicate: How to create polygons with straight lines and right angles in QGIS? In QGIS 1.8 is there a way to digitize buildings etc. with perfect 90-degree angles, Or, edit a polygon ...
2
votes
2answers
406 views

Digitized Shapefile manually using wrong projection: how to fix it?

I have a raster in correct projection. I used shapefiles, and marked objects (manually), but I found out that my vector layers have different projection, so they have different size and position. Is ...
2
votes
1answer
491 views

Line to polygon conversion

Currently we are working in a geological project..in which all the Contacts, Linear & some other geological features have to be captured. The thing is most of the features have to be Captured as ...
2
votes
1answer
402 views

Heads up digitizing - Polygons overlay differently with two different Satellite images

I have been digitizing building footprints from satellite image using ArcGIS 10.1 . Field data collections is done with the use of four corner point GPS way point. Due to multipath errors, we are ...
2
votes
1answer
5k views

When I finish drawing a polygon, it disappears again (although appearing in my attribute table)

I'm working with Quantum GIS at this moment. And as the title says, when I finish drawing a polygon, it disappears again. The new object does appear in my attribute table and in the legend/'filling of ...
1
vote
2answers
3k views

Converting *.jpg scanned from line paper map to vector data in ArcGIS for Desktop?

I want to digitize automatically old paper map that scanned to jpg . I know that it's possible to digitize it with arc-map but I can not remember how to do it.
1
vote
0answers
330 views

Shapefiles not editable anymore?

From this morning if I open a qgis project all the shapefiles are not editable anymore. I've tried different projects in both 2.14 and 2.16 qgis versions. Has anyone encountered the same problem?