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3
votes
1answer
45 views

Converting a NAD27 Lambert Conformal Conic custom projection to WGS84 using QGIS

I am trying to convert some points from NAD27 Lambert Conformal Conic (custom projection) to WGS84 using QGIS 2.8.9. I am using the datum transformation parameters for El Salvador published here: ...
1
vote
1answer
55 views

Positive Topographic Openness - do any FOSS tools (other than SAGA) provide this?

I'm looking for a FOSS GIS tool to provide Positive Topographic Openness on 32-bit Ubuntu. (which rules out ArcGIS) Normally I use SAGA GIS for this, but my Ubuntu setup is a bit messed-up after a ...
1
vote
0answers
31 views

$length calculation anomaly

A polyline layer's (green) length is being calculated via $length. Result: ~100 meters (EPSG 31466). A buffer of 5meters is created and via Voronoi Polygons (and several other steps) a centerline ...
2
votes
1answer
23 views

Get Altitude for Multiple Objects

I use QGIS and I has two layers: one with point objects (more than 1000) and one with surface (it is a version of DCW). I want compute altitude of all points. Basically, I want to get an array where ...
1
vote
1answer
19 views

Display card problem in the browser [closed]

I'm having a trouble with the extent. I don't know how to get them in QGIS and I need to display a map with two layers in a website. For this I used OpenLayers and MapServer as WMS server to serve my ...
1
vote
1answer
36 views

QGIS - Show count of same attribute in feature (on visible map or by same field)

In QGIS 2.14 I have a feature with two fields; Element Type (TF1, TF2, TF3, TF4) and Trail Nº (1, 2, 3, 4, 5, 6) Each Trail has multiple Elements. I.E. Trail 1 may have 6* TF1 and 2* TF2, while ...
4
votes
1answer
49 views

Make field in QGIS unvisible

I want to use some fields in qgis form but to make it unvisible in table. Is there any way to do it? Now if I make the field property unvisible - I can't use it in the form. I'll be glad to see any ...
3
votes
2answers
35 views

broken plugins with QGIS install

I have been struggling with this for a bit. I recently upgraded my qgis to 2.8.9, and now am having issues with the ftools plugin as well as the processing plugin. When I start qgis, I get this error: ...
6
votes
2answers
88 views

How to calculate the difference between two rasters in QGIS?

I have two similar rasters of the Mount Vesuvius and surroundings: one spans 20 kilometers, and the other one 50 kilometers. The two rasters are overlapping: What I would like to do is to create a ...
3
votes
2answers
71 views

How georeference a dxf file in QGIS 2.14?

In Illustrator I exported a PDF as dxf and inserted it in QGIS as Vector and obtained 2 layers as points and lines but it is misaligned and in a unknown location. I know georefecence a raster file, ...
0
votes
2answers
41 views

Digitizing Tools error in QGIS

I receive this message: Digitizing Tools: Amend Line is disabled because layer CRS and project CRS do not match. If I set the CRS of the layer the same as the project CRS (W84 Pseudo Mercator) is ...
3
votes
2answers
42 views

Search for textbits in QGIS

Is there a way to search for only parts of text in QGIS. Imagine I have a field in my attributetable called myField and I have several entries there, something like This is awesome Even more awesome ...
1
vote
0answers
29 views

Generate more nodes for routing

The following picture shows my routing database all set for querying loaded to QGIS. Red line is the road I want to select route from, yellow points are the vertices generated after running ...
6
votes
1answer
150 views

How to make a automatic updated date and time field in QGIS 2.14?

I want to make a date and time upadated field as I edit an attribute field in this format yyyy-mm-dd 00:00:00 (= 2016-05-08 11:04:00) - my local date/time. The data is in a QGIS 2.14 shapfile and ...
3
votes
1answer
37 views

incorrect skewed re-projected Grid lines in TileMill

I am working on a project in TileMill for the first time. I am trying to overlay a Graticule of the British national square grid. I generated a series of LineString for the grid into PostGIS, which ...
1
vote
0answers
22 views

QGIS - Split a line having attributes with UNIQUE constraint

I am using QGIS with a PostgreSQL/PostGIS database, where the lines table (named 'segments'), besides the integer serial primary key, has a UUID column having a UNIQUE constraint. Trying to split a ...
3
votes
0answers
26 views

GRASS7 r.water.outlet doesn't run correctly in QGIS 2.14.2

I am a new user of GIS software and I am currently facing an issue with the GRASS7 tool `r.water.outlet. I am a beginner with both Linux and GIS. I am using Ubuntu 14.04 with QGIS 2.14.2 and GRASS ...
1
vote
1answer
44 views

QGIS processing framework Python loading shapefile

I would like to write a Python script in the QGIS processing framework allowing the download of files from specific addresses. Instead of starting my script with: vectorLyr = vector I would like to ...
3
votes
1answer
61 views

Are calculated fields available in any database that Qgis can use

I'm trying to find a data storage method that can handle up-datable calculated fields (such as population density=population/area). I want to be able to alter the population as the data changes (like ...
1
vote
3answers
49 views

How do I separate .txt data into multiple columns when exporting to .CSV?

I have .txt data that is described as Lat Lon Elevation (meters) and when I export to .CSV in Excel it puts all data into 1 column. So when I import the data into QGIS it all dumps into 1 column, and ...
3
votes
0answers
53 views

Render Vector & Save as Raster

I am working with ENC files from noaa, specifically S57 format or ".000" to be as specific as possible. I am trying to render a layer or even the entire thing in a window but have had no luck. ...
1
vote
0answers
14 views

How to get the name of the layer on a map composer with a single layer?

I tried layer_property( 'layer', 'title') I would like to return the current layer from the map instead of 'layer'. (or list of the layers on the map?) Doesn't seems to works with layer_id or ...
0
votes
0answers
25 views

Activating LAStools - 'wrong value for parameter “Msys folder”' [duplicate]

Whenever I try to activate LAStools, I get the following error, despite setting the path as /Users/grant/LAStools/ - which is its actual location: Wrong value for parameter "Msys folder": ...
1
vote
0answers
37 views

Converting Shapefiles

Can anybody help me on how to convert shape files into .asc files? I want to convert layers from shape files into this format but I don't know how to go about it in qgis.
3
votes
1answer
60 views

How to convert from a local coordinate system to UTM (and vice versa) using mathematical expression

I have two coordinate systems- UTM Zone 23S and a local one with the following conversion from UTM to Local: EASTING: SQRT( (UTM_EAST-296787.355)^2 +UTM_NORTH-8095123.271)^2) ...
1
vote
2answers
56 views

Is there a plugin or another way to quicky edit the attribute features in QGIS?

I want to edit the field "name" of several roads in QGIS 2.14. How to do it very quickly? Currently I select with "Identity feature" tool that open Form Feature Attribute, then with the mouse I ...
3
votes
2answers
100 views

QGIS: Legend with more columns in one row

I have two layers (water_supply_design, water_supply_condition). I'd like to create new map with Map Composer in QGIS. In this map, I'd like to have a legend with one row and two columns (Water ...
2
votes
1answer
49 views

How do I use geometry object in processing.runalg()

I am trying to clip a polygon (large road network) with every row in another polygon (district polygon) using PYQGIS. layer_adm_level = QgsVectorLayer(base_path + adm_level + ...
1
vote
0answers
21 views

qgis web client zoom and center maps

I have a problem with " qgis web client" I can not find the option setting center of maps and change the zoom ?? I was looking at globaloptions but I managed to ; / Regards
1
vote
0answers
35 views

How to draw weighted voronoi polygons ( thiessen) from points in Qgis?

I have a shapefile of polygons which have an amount of population, I need to divide each of these polygons into small ones with nearly equal population. So I thought attributing points on each area ...
1
vote
0answers
26 views

Why is the QGIS 2.10 raster clip function not working correctly?

I am using QGIS 2.10 and everything seems to work just fine so far, except for the raster clipping function (Raster>Extraction>Clipper). I'm using a vector poligon as a mask layer, but after launching ...
4
votes
1answer
80 views

How to write Python code with QList class

I need to write an interpolation script for QGIS. I want use TINInterpolation method from Interpolation plugin. I found class in API documentation but I don't know how to write QList object with ...
1
vote
0answers
17 views

Automating the Road Graph “shortest path” plugin in QGIS to batch compute routes

Is anyone aware of how to automate the Road Graph "Shortest Path" plugin in QGIS, calculating multiple routes from multiple origins to multiple destinations, using two point files and road network, ...
1
vote
1answer
59 views

Measuring Volumes using DEMs

I've done quite a bit of research here and elsewhere and am still having trouble coming up with a solution for measuring volumes using a DEM derived from high-resolution (1 m) stereo satellite ...
5
votes
1answer
75 views

How to create points along a line according to attribute data in QGIS?

I would like to create equidistant points along lines in QGIS, but each of my lines have an attribute of how many points should be on them in a column called "piece" and these values are different in ...
2
votes
0answers
16 views

rename table/feature class in filegdb using ogr or qgis

According to the OGR SQL docs, it doesn't appear that it is possible to use and ALTER statement to rename an existing table (featureclass) inside of a file geodatabase. RENAME statements can be run on ...
4
votes
1answer
59 views

Why QGIS WFS doesn't update PostGIS line and polygon layers?

I installed PostgreSQL and PostGIS and created PostGIS layers in GeoServer. But when i want to change geometry in QGIS via WFS it drops an error: ": Error performing insert: java.lang.String cannot ...
3
votes
0answers
51 views

How to generate static heat maps server side?

I've been searching a way to generate server side static maps using Python (or any other languages, doesn't matter) I can create the maps I want with Qgis (And they look really great) but I don't ...
3
votes
1answer
51 views

Importing large .asc files into QGIS

I've been given two .asc files containing a 1m raster data from a LiDAR survey. I only have access to QGIS.2.14.1 (which I'am using for the 1st time only having previous experience with ArcGIS) and I ...
0
votes
1answer
23 views

Comparing areas of overlapping shapes in QGIS

Given SHP files for a country's Districts in Year1 and Year2, how to output a table whose rows state the percentage composition of each Year2 District in terms of portions of Year1 Districts
0
votes
1answer
16 views

R.patch creating enormous file size

I'm using r.patch (within QGIS, GRASS 7) to patch two Float32 rasters both of which have a respective filesize of under 200MB. When I save the memory layer raster created by the r.patch function, the ...
4
votes
1answer
44 views

Positioning of graticule labels in QGIS 2.14.1

I have a map grid (line, shp) that was created with MMQGIS. The X and Y coordinates of the lines are stored in the the attribute table, which makes labelling the lines an easy process. My problem is ...
2
votes
0answers
45 views

QGIS managing relationships

Coming from an ESRI background I'm used to ESRI geodatabases (.mdb or .gdb). In those databases, I could create feature classes, tables and relationships between them. Every time I loaded a feature ...
1
vote
1answer
63 views

How to digitize 3D geospatial data using FOSS applications

I need to digitize soil horizon data from photos to be later used in a 3-dimensional GIS workflow. For each photo I have DGPS coordinates of the top left and right corner and the depth of the ...
3
votes
1answer
68 views

Application of preset properties QGIS layer to another imported shp

In QGIS I import the same shp files during days (continuously fieldwork). For processing in QGIS I set the properties of layer (imported shp)- Style, Labels, Actions, Display. In these days I have to ...
2
votes
3answers
67 views

Merging tif images into a single GeoTiff with QGIS

For this example, I have 3 tif images that are tiles. They fit together to form a single image. I load the 3 images into QGIS and it merges them directly and I see my completed image. The problem ...
1
vote
0answers
24 views

QGIS “buffer” considering grades

I have to develop an article entitled as "GIS IN ASSESSMENT OF BUS TRANSIT SYSTEM ACCESSIBILITY CONSIDERING GRADES". I'm still at an early stage of development of the research project, but I have ...
2
votes
0answers
21 views

PyQGIS: intersection of one node layer with two polygon layers

I´m new with the use of PyQGIS and I´m working in a problem applied to a water supply systems modelling, where I need to distribute the water demand in about 5000 nodes (network junctions). I´m ...
2
votes
0answers
14 views

Issue loading PostGIS out-db rasters (either in QGIS or MapServer)

I'm playing with a few different options of storing raster data via PostGIS to visualize (eventually in a web app). The out-db or out-of-database storage seems the best option, but I can't seem to ...
1
vote
1answer
21 views

qgis feature classification of filegdb datasource bug?

When I am trying to create a symbol classification from a filegdb datasource in qgis the list of unique attribute values is not being populated when I hit the 'Classify' button. It loads a single ...