12
votes
0answers
688 views

How to reverse-georeference with QGIS?

I have a map with a "strange" projection (it's basically hand-painted, not an exact one). I can easily georeference it in QGIS using the Georeferencer plugin and the Thin Plate Spline transformation ...
10
votes
0answers
297 views

PyQGIS save raster as rendered image, then use GDAL tools on it

I have tried to use the code from QGis Save Raster as Rendered Image. i is a raster layer: pipelayer = i pipeextent = pipelayer.extent() pipewidth, pipeheight = (pipelayer.width(), ...
9
votes
0answers
259 views

How to extract sublinestring from a linestring with overlapping segments

Problem statement: Given a bus route (defined as a linestring ln.the_geom), and a set of bus stop locations (pt1.the_geom,pt2.the_geom,...ptn.the_geom), divide the bus route into segments between bus ...
8
votes
0answers
92 views

Accessing the internal data structure storing Postgis spatial index (PostGres GiST)

I am curious about how the internal data structures and storage mechanism of the spatial GiST index in Postgis. In Oracle, I used to like to show how the SDO indexes were "just another table", and how ...
8
votes
0answers
155 views

How to access a deleted features attributes (before committing)

I have a signal setup for a feature deletion event on a layer: self.layer.featureDeleted.connect(self.feature_deleted) When I try and grab an attribute from the deleted feature on the slot, a ...
8
votes
0answers
180 views

Can GRASS compute the line graph representation of an input graph?

I'm interested in computing a line graph for an input graph, preferably in GRASS since I'll be using other GRASS network analysis tools afterwards. I couldn't find any reference to line graphs in the ...
8
votes
0answers
236 views

Joining layers with respective elements with PostGIS Topology

I'm currently using PostGIS topology extension, but I have some difficulties in understanding how the structure works: One of the key points is the use of "layer"s: as of what I understand, features ...
7
votes
0answers
257 views

Automating creation of ServiceDefinition from Python script tool of ArcPy without broken project data source?

Summary: I can create a ServiceDefinition through ArcCatalog or ArcMap, but when I try to generate the ServiceDefinition through python, it does not copy the /data folder with it, thus the script ...
7
votes
0answers
206 views

Spatial query too slow to handle bigger OSM extracts

I'm trying to compute some statistics for OSM data using PostgreSQL 9.3.5 and PostGIS 2.1.4. I started with a small bavaria extract which I downloaded from Geofabrik. The db schema is the normal API 0....
7
votes
0answers
266 views

Frontal Detection of sst & Chlorophyll image

I am working on sea surface temperature satellite images and looking for delineating gradients in open source on the basis of temperature. Is there any tool like Cayula and Cornillon front detection ...
7
votes
0answers
147 views

Geoserver dxf plugin - How to export attributes labels?

I'm trying to export from Geoserver a set of layers with WFS request and dxf plugin for dxf conversion. There is an option withattributes:true that I have added for each vector layer a ...
7
votes
0answers
358 views

Performing buffering and intersection with script in PyQGIS

I wrote a script that performs the intersection of two layers: The first Layer -> layer1, represents the rivers The second Layer -> layer2, represents a set of circular dots distributed in a ...
7
votes
0answers
183 views

Add attribute table to a raster in postGIS

I would like to add attributes to a raster stored in a postgis database. I use the following command to insert the raster in the database: raster2pgsql -s 4236 -I -C -M /home/user/mysrc/outlabeled....
7
votes
0answers
260 views

Why do file geodatabase and SDE readers produce different fme_geometry types?

I have one very simple workbench that I am running against both SDE (9.3) and FGDB (10.0) sources. I noticed two different fme_geometry values for same type of objects. For the first one, i.e SDE 9....
7
votes
0answers
701 views

Grouping analysis of points to divide polygon into n number of sub-regions using QGIS?

I'm attempting to create n sub-regions from a polygon based on a cluster analysis of a bunch of overlapping raster layers (physical layers, eg: depth, currents, waves). Briefly, I can create a ...
7
votes
0answers
436 views

What to do about Geoserver WPS warning“ ”Could not get a ServiceInfo"?

This is the warning I am getting when I try to use this WPS service from QGIS, and the processing time is taking too long, but doesn't terminate. What might be the problem? 17 Oct 12:33:25 INFO [...
7
votes
0answers
691 views

How to get rpy2 for QGIS on OSX?

I am a new QGIS user, have installed QGIS on a Mac running Snow Leopard OSX 10.6.8 following all the instructions. QGIS seems to work well for everything other than when I boot up I get the message "...
6
votes
0answers
52 views

How to undo field calculation in ArcGIS Pro

I am using ArcGIS Pro and cannot find a way to undo field calculations. With ArcGIS, field calculations could be undone when an edit session was active, but Pro seems to be in a perpetual edit ...
6
votes
0answers
78 views

Development of a plugin which depends on an external Python library

I'm developing a Python plugin, the target is integrating into QGIS the functionalities of a PyPI Python library called 'elevation'. Is there an OS independent way of installing external Python ...
6
votes
0answers
50 views

How to synch a FeatureTable with a FeatureLayer's selection set?

The ArcGIS Server JS API contains a new FeatureTable class, which shows the attribute table corresponding to a FeatureLayer. There is an option syncSelection which: Enables an interaction between ...
6
votes
0answers
57 views

Automatically style raster using unique values in QGIS?

In ArcMap, it is possible to automatically calculate the unique values for a raster and then apply a different style to each unique value (see 1st image). However, in QGIS, I have to manually add ...
6
votes
0answers
108 views

Using memory layer as input and/or output with runalg?

Can a memory layer be used as an input and/or output with runalg? With runandload I get this to work: processing.runandload("qgis:mergevectorlayers","memory:bufferOne", "memory:bufferTwo", r"memory:...
6
votes
0answers
49 views

Preventing invalid values in PostGIS geography

If I use pgAdmin to insert a point with an invalid latitude, say 91°, I receive the following notice before the query completes successfully: NOTICE: Coordinate values were coerced into range [-...
6
votes
0answers
141 views

How do I get layers' IDs using python?

I am working in an ArcMap session, I've checked the option to get an ID for each of the layers in my document, so anyone has it. Now, what I need is a way to get these values within a python script ...
6
votes
0answers
89 views

Perform QGIS modeler multiple raster calculations with data from external CSV

I need to perform multiple calculations on a set of rasters based on values in a CSV metadata file. I'm using the QGIS graphical modeler and can call a specific field in a CSV with the Table and ...
6
votes
0answers
127 views

Is there a way to pause WMS layer auto refresh in OpenLayers 3?

I have an application which has to perform a HTTP request (which will handle some map transformations) before fetching WMS tiles from server. Is there a way to pause TileWMS auto-refreshing after ...
6
votes
0answers
92 views

Exotic Projections QGIS

I would like to use some projections in QGIS that I can't see supported directly. An example would be something like this conformal cube projection. http://www.csiss.org/map-projections/...
6
votes
0answers
78 views

Styling polyline to view which part is above another in self intersection using QGIS?

I need to view a polyline constructed from waypoints of a gps track, that has self intersections in curves, like an exit loop from a highway. I need to visualize it in a way that allow to know which ...
6
votes
0answers
103 views

GeoJson structure

I currently designing a table/document database structure and use GeoJson to store points and routes. Currently I choose MongoDb, I will consider PostGIS later. I want to store route info for public ...
6
votes
0answers
330 views

Add vector tile sources to QGIS

Is it possible to add vector tile sources (using MapBox's protocol buffers format, or GeoJSON, or otherwise) to QGIS? If so, how? (My question is a bit similar to Can the new Mapbox Vector Tiles be ...
6
votes
0answers
823 views

What are the Differences Between TMS, XYZ & WMTS?

There are currently three different ways of Serving out Tiles: TMS WMTS XYZ I do know that XYZ is now the most popular one, and is used by services like Google, Mapbox, OSM and many others. What ...
6
votes
0answers
331 views

Why is QGIS georeferencer much faster on Windows than Mac?

I just went from temporarily using a Windows 7 machine with 4GB of RAM and no video card as far as I know. I'm now using a mac with 16GB of ram, etc. Its a much more powerful machine. However, QGis's ...
6
votes
0answers
839 views

PostGIS: Merge any and all adjacent polygons

I would like to do adjacency tests on a parcel (polygons) layer and merge them if they fit certain criteria (could be size). Per the picture below, I would like to merge polygons 1,2,3 and 4, but not ...
6
votes
0answers
153 views

Postgis database query optimisation

I have a set of rasters in DTED format which I load into postgis database using raster2pgsql command line tool. Each of rasters is simply stored in a row and described by rid and a value of raster ...
6
votes
0answers
312 views

ArcObjects : Out of Server Memory when reconciling a large edit session

One of our users has been periodically experiencing Out of Server Memory errors with ArcSDE 10.0 when trying to reconcile a large edit session. VMware ESX Instance: Windows Server 2008 R2 ...
6
votes
0answers
578 views

Printing/exporting WMTS tile layer with desired resolution / zoom level in QGIS

I have a project which uses WMTS and some vector layers in QGIS. I can freely zoom in and out, and tiles are refreshed with appropriate zoom level, just as expected. Now I would like to export part ...
6
votes
0answers
896 views

How to use the linear referencing plugin from QGIS with postGIS data?

I need a guide how to use this plugin properly, I'm a newbie on PostGIS and I'm trying to use the linear referencing plugin of QGIS. I've created a database on postgreSQL with the postGIS extension ...
6
votes
0answers
334 views

QGIS: How to reverse vertex ordering in polygons

I am working with an Oracle spatial connection in QGIS through which I am accessing and editing a vector layer. I find that when I edit a geometry, the vertex ordering is reversed (to clockwise in the ...
6
votes
0answers
513 views

How do I install Orfeo toolbox and Qgis 1.9?

I'm having a lot of trouble getting Orfeo toolbox and Qgis 2.0 working. I followed the qgis wiki instructios, added the ppa, installed qgis 1.9 (it's beautiful, great work!). But when i tried to ...
6
votes
0answers
2k views

How do I solve Gdalwarp error 'too many points failed to transform' for remapping Geostationary to Lambert conformal?

I am trying to remap from Geostationary to Lambert conformal using gdalwarp. My input data is in netcdf, and is in geographic coordinates (degrees) and I would like to output the remapped data to ...
6
votes
0answers
226 views

GeoServer pregeneralized layers not working as expected

I've set up GeoServer 2.1.4 and installed the feature-pregeneralized-2.1.4.jar plug in and processed my shape files into each of their separate folders with the generalized shapefiles and I've check ...
6
votes
0answers
408 views

Translate Orientation from Sensor data to Geo location

I am tracking a device that might loose GPS signal then and there. And when the GPS signal is too low, I should use the accelerometer and Gyroscope sensors data to guess which way they should have ...
6
votes
0answers
1k views

How to create point labels from midpoints of road polylines in QGIS?

Heres what i want to achieve: i have a roading polyline layer (singlepart ie has several features per road, grouped by an id field), and i want to (after merging the parts) find the mid point of the ...
5
votes
0answers
52 views

Sending a https request from a QGIS plugin using urllib2

I'm developing a QGIS plugin that needs to send https request to an API. I have to use urllib2 (see below if you want to know why I don't just use the requests package) The first request I need to ...
5
votes
0answers
97 views

OSMDroid android app zoom in without changing tiles, is it possible?

I am developing an android mobile mapping app using OSMDroid 4.3. I have established a basemap using arcgisonline as my tile server. String[] urlArray = {"http://server.arcgisonline.com/ArcGIS/...
5
votes
0answers
53 views

Where are the default layout templates stored for ArcGIS Pro?

Previously in ArcMap 10x you could save custom layout mxds to C:\Program Files (x86)\ArcGIS\Desktop10.3\MapTemplates or C:\...\AppData\Roaming\ESRI\Desktop10.3\ArcMap\Templates. However I cant seem to ...
5
votes
0answers
98 views

Different results from GDAL raster attribute table command on mac and windows

I am trying to get the raster attribute table of the following file: Shift_cult_past_current_prediction_20160107_gr1DD.tif available here: https://www.dropbox.com/s/fmomfpro3j6dmz8/...
5
votes
0answers
126 views

Finding density centroids within polygons in PostGIS

I want to find the highest density of OpenStreetMap nodes within a dataset of census geometries. I want to tie the census data to the location of the node which is most central in terms of population. ...
5
votes
0answers
68 views

Is it possible to use a raster::click event within an interactive leaflet map?

Data Download: https://www.dropbox.com/s/f849ra8l6umo9d8/crops.tif?dl=0 I have various raster images of the world that I would ultimately like to plot within an interactive leaflet map; an example is ...
5
votes
0answers
101 views

How to fill composer map with canvas data and export composition as png using Python script in QGIS

I'd like to create a Python script in QGIS that will take some data (shp + tif, in my example), use tamplate Map Composer (from a file) and export created composition to a png image. With almost no ...

15 30 50 per page