Tagged Questions

A layer is a collection of information. It contains specific elements of a gis in a specific presentation method (e.g raster or vector layer). Layers can be edited separately in order to create individual toppics for a map.

learn more… | top users | synonyms

1
vote
1answer
150 views

How to sum the values for bins with the same location?

I have two maps in csv form, each has a latitude, longitude, and value column. Since not all the positions in one map are in another map, is there any way in QGIS to display a new map which only shows ...
1
vote
1answer
170 views

How to make a virtual layer from ogr geometry?

I know how to do this: nodes = driver.Open(node_nav,0) node_lyr = nodes.GetLayer() node_lyr.SetSpatialFilter(None) But how do can use the layer methods on a geometry I created from scratch? ...
2
votes
1answer
321 views

GeoExplorer: “Could not create layer record for layer group”

I installed GeoServer via OpenGeo Suite, and still working on it. I created a "Layer Group" and add layers from local PostGIS. I tried to preview it from "Layer Preview" and show perfectly through ...
1
vote
1answer
580 views

Creating a layer after using SelectLayerByAttribute_management

Is it possible to use an existent layer to do a selection by attributes without having to use MakeFeatureLayer_management first? Because I already have a layer with the same name as the feature class ...
0
votes
0answers
44 views

How can I import layers into a database?

According to the QGIS User Guide (release 1.8.0, page 203/204) I only have to drag a layer from the QGIS Browser to the DB Manager. But for me this does not work.
1
vote
1answer
577 views

QGIS python - reference a layer in the table of contents

I'm trying to create a plugin for QGIS using python, But need some help. I want to 1.Zoom to a layer and 2. make the layer visible(switch off or on). But I have managed to zoom to an active layer by ...
1
vote
1answer
199 views

Geoserver api: how to determine a layers respective workspace?

I am using the geoserver api to find information about layers that are available. I am using: http://localhost/geoserver/rest/layers.json to get a dynamic list of all layers. If I then select a ...
1
vote
1answer
148 views

Rendering order of layers in QGis libraries

I am using the QGis libraries in a external Qt App. When adding vector and raster layers (in any order) to the QgsMapLayerRegistry instance, it somehow sorts the layers so that the vector layers is ...
1
vote
1answer
84 views

How to copy a layer in TileMill?

I've been learning to use TileMill, and I want to be able to copy a layer. I especially want to copy layers connecting to an SQLite or PostGIS database in order to avoid having to type in multiple ...
2
votes
1answer
211 views

OpenLayers - How do I change the WMS URL in Code

I want to be able to change the url for a layer in code. The reasons is that I am implementing local caching. When local caching is Not enabled, we use 4 servers to deliver tiles to run parallel ...
4
votes
4answers
1k views

How to get vector data from OSM to use in QGIS?

How do I get data from OpenStreetMap which I can then edit in QGIS layer by layer? What is the best OSM output and what / how do I get to a suitable input for QGIS? OR...is there another appraach to ...
1
vote
1answer
130 views

QGIS Layers Not Lining Up

I am new to QGIS, I have been using ArcGIS for most of my maps. I have two layers that are not overlapping properly. One is a shp file from a GIS clearinghouse and another from a delimited text ...
0
votes
1answer
381 views

How to resolve error “Handle bad layers” in QGIS?

I'm new to QGIS and have been seeing what it can do for me – seems good. I imported shape file data from a UK Ordnance Survey data file and saved the file in a new folder. It was very good, doing all ...
0
votes
4answers
1k views

How to merge 48 separated US States layers into 1 layer, using MapInfo?

They are Census Block layers. The person on the website separated them into states so they can be download easier. I uploaded each states separate layer into MapInfo. Now I need to merge the files ...
1
vote
0answers
219 views

How to load the default layer style from Postgresql with Python?

I would like to write a python macro that upon opening my QGIS project file will reload the default style for each layer from the postgres 'layer_style' table. I have had a look at the documentation ...
2
votes
1answer
497 views

Can one convert text annotations to a layer in Qgis?

I know text annotations can be turned on & off with Ctrl+T... but is there any way to export them as a layer? Thanks!
2
votes
2answers
316 views

How to load layers from postgis to dotspatial or sharemap viewer

I want to develop a PostGIS viewer for PostgreSQL (with SQL query editor) to visualize PostGIS layers. Which spatial library (.net C# supported) do I have to use?
1
vote
2answers
2k views

How To Highlight Roads?

I wish to change the colors of various roads on a map and save the changes to either a "personal map" or a "map layer." The personal map could look something like this, except it would need to have ...
0
votes
0answers
108 views

“could not get any sources: no image returned from source WMS” error in mapproxy demo

I am trying to connect my mapserver to MapProxy. First part of the map file is shown below MAP FONTSET "fonts.lst" IMAGETYPE png MAXSIZE 4000 SIZE 800 800 EXTENT -20000000 -20000000 20000000 20000000 ...
6
votes
1answer
624 views

How to add layer with ArcPy and retain feature class metadata (like Credits) in layer properties?

I have multiple feature classes in a geodatabase, each feature class has metadata including a Description, Credits, and other information. If I use the 'Add Data' button in ArcMap 10.1 to add one of ...
1
vote
0answers
180 views

Adding multiple layers to Tilemill from a single sqlite DB

This is a repost of a question I had over at the MapBox support board. Since I wasn't having much luck over there, I'm hoping I would have better success here. I'm having trouble adding more than a ...
1
vote
0answers
256 views

Handling “bad layers” in QGIS version 1.9

I'm having a problem every time I try and open any project in qgis 1.9. It will load part of a few layers and then a yellow bar comes up across the top of the map area that says "Handle Bad layers: 23 ...
0
votes
1answer
844 views

Marker layer not responding to events in OpenLayers

I have multiple layers in OpenLayers: three vector layers, one google map layer, and a marker layer. I registered feature selected event to all three vector layers (which works fine, but btw is that a ...
1
vote
2answers
353 views

ArcGIS 10.1: “ERROR 000223: Cannot extract event table properties” when iterating through multiple files/folder

I am trying to convert ~270k csv-files with lat/long-data to layerfiles. The files are split into folders by year, i.e. ~30 folders with ~9k csv-files in each. I have written a script to iterate ...
3
votes
3answers
471 views

What Is The Ideal Workflow To Map (British) Postcode Territories

I'm looking for the best workflow for mapping postcodes and calculated territories, but being relatively new to mapping I'm struggling on a few details and also the best practices for displaying these ...
1
vote
1answer
150 views

Openlayers Overview - disappearing layers

when I do this: var options = { autoPan : true, size : new OpenLayers.Size(300, 200), layers : this.map.layers, mapOptions : { allOverlays : true ...
0
votes
1answer
172 views

How can i select many rows from a table?

I want to create an action that select many rows from PostGIS table to show many lines in QGIS. How can i select many rows from table with python to add these rows in a layer? Thank you
0
votes
0answers
88 views

Create Layer including drawing objects

I draw some polylines on map. How create new layer with this features? Map and Polylines must be in different layers. public void DrawPolylineUsingInputGeometry(IActiveView activeView, ...
1
vote
1answer
206 views

How can I change SQL query through a layer of an action (python)?

I have three layers from three diferent database tables. When I click in other layer I want to change (with an action) the query of that three layers. How can I do that? Thank you
5
votes
3answers
2k views

How can I set the base layer of map before initialization?

I have been using map.setBaseLayer(layer); to switch to my preferred map layer, using the localStorage variable layer that is stored in my web browser, upon initialization of the map. But I realize ...
0
votes
1answer
116 views

In QGIS can I show just the lines in a Postgis query? How can I do that?

I have three tables in Postgresql, each table with one layer of lines. I want to show the path of an initial line to another final. Is it possible executing a SQL query? Thanks My three tables are ...
3
votes
1answer
176 views

Performing a field calculation affects selectable layers in ArcGIS 10.1

In ArcMap 10.1 I have a table open for a layer that I have set as not selectable. Yet when I use the Field Calculator for a record(s) in that table, it automatically makes the associated layer a ...
2
votes
1answer
108 views

Join attributes by date in Qgis

I learned (thanks!) to use the join feature built into the layer properties, but in my case it doesn't work because data do not match perfectly. Infact shape refers to geotagged photos, csv is a log ...
1
vote
0answers
192 views

How can I move two layers at once in QGIS?

I'm trying to move two digitized layers, one containing points, the other polygons to a different location at the same time. QGIS doens't seem to allow this. Even if I select both layers and features ...
2
votes
1answer
277 views

Using multiple LayerIDs in a Legend

This should be simple, but I cannot find any documentation on how to do it. I have a legend that is bound to my map that contains several layers. I do not want all of the layers to appear on my Legend ...
1
vote
0answers
71 views

proportion of image layer in OL

I tried create map with single image used OL. But I have a trouble: image in map has a wrong proportions. Img: 1540 x 1481 Img in map: 2858 x1481 My js code: $(function (){ var map = new ...
4
votes
1answer
3k views

How do I add my own map layers to Leaflet

I have a Leaflet map and want to add two of my own small polygon layers (currently in shapefile format, but they could be converted to GeoJSON). Can this be done without a mapserver to publish them ...
1
vote
2answers
103 views

How to specify one layer among many with getWMSInfo?

I am using getWMSFeatureInfo with multiple point layers. When I click on a point on map, how to specify which layer that point belongs to?
1
vote
1answer
55 views

geoserver returns incorrect number of points when cql used

I'm using Geoserver 2.2.4 to support WMS queries. All testing is done via the "Layer Preview" page. If I send a request with no CQL a map full of points is returned as expected. If I add a CQL ...
0
votes
1answer
183 views

How do I style lines to show gradient colors for two attributes?

I have a layer with the city streets. I have a database with traffic values, including traffic going into the city and traffic going out from the city. I need to show the street links with different ...
0
votes
1answer
148 views

Split Map using Python in Qgis

I have a map, in which each region is defined as an attribute of the map (I can select each region from the attribute table). I am trying to create new layers each one containing only 1 region using ...
0
votes
1answer
605 views

Feature Layer Selections

I'm new to arcgis and arcpy, so some of my lingo and terminology may be off. I have a script that takes a feature layer as an ainput. From there I want to be able to count the number of selections in ...
2
votes
2answers
2k views

How to clip a layer file

I have a world imagery layer that I want to clip to a single county. I would just save as a JPEG and edit using other software, but this uses a lot of processing power if I want a high resolution. I ...
1
vote
1answer
136 views

What ArcGIS Online feature layer can I use to display European states with unique country codes?

I'm writing a web page to display ECB statistics on an ArcGIS JavaScript API-based web map. I'm a bit lost when selecting a feature layer so that I can use the UniqueValueRenderer to make the states ...
2
votes
2answers
500 views

Managing a large number of layers in OpenLayers/GeoExt and Geoserver

I am building a web application to facilitate the handling of approximately 2500+ historic maps. I think it would be too difficult for our users to search for specific maps in an ordinary layer tree. ...
1
vote
1answer
2k views

How to manage user privilege on layers to Arcgis 10 Desktop?

Problem: I am a Computer Analyst on a town hall. Here we have the sector A and B. Both work in ArcGIS 10 Desktop. The sector A has granted to access/edit everything. The sector A has all the ...
0
votes
1answer
101 views

How can I create a button to add a POI layer?

I am making a map of a city with openlayers. I have the shapefile data of the POI (hospital,bank,school etc.) I want to add the layers with buttons not in layerswitcher. Like whereis.com's quick ...
1
vote
1answer
328 views

Get feature from two overlapping KML layers doesn't work

I did an implementation similar to http://openlayers.org/dev/examples/sundials.html The difference is that I have two or more kml layers at the same location and want to show their information ...
2
votes
1answer
393 views

How to realign (PostGIS) layers in QGIS?

I'm trying to realign layers in QGIS. As you can see here, the "background" light-blue layer is not aligned with the top layers. I'm working with pgAdmin III and importing PostGIS Layers in QGIS. My ...
2
votes
1answer
2k views

Layer visibility using maxscale minscale not working

I'm using Openlayer and Geoserver. I have a series of layers that have a scale parameter like: 1:50000-1:25000 where 50000 is the max scale while 25000 is the minscale. I have a map like in this ...