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.
7
votes
2answers
852 views
How can I iterate over map layers in QGIS python
I'm having trouble figuring out how to iterate over map layers. I can access the currently highlighted layer in the table of contents via iface.activeLayer() but I want my code to operate on all ...
6
votes
4answers
1k views
How to georeference a vector layer with control points?
I have a non-georeferenced vector layer that I need to be georeferenced. With raster layers the task is easy and straightforward, but I have no idea what should I do with my vector layer. I have a few ...
5
votes
1answer
346 views
MXD Performance - number of layers vs number of datasets
My mxd currently has 5 buildings layers accessing 5 different buildings datasets (one for each of 5 counties). Most often there would only be a single county's buildings in the current view, if that ...
5
votes
1answer
521 views
How do you symbolize a feature class layer in ArcMap 10 based on one attribute's value and then another attribute's value?
I currently have a point feature class that has a couple of attributes that I want to use to symbolize its layer. One of the attributes is called ExceedsTolerance, which either has "Y" or "N" for its ...
5
votes
1answer
272 views
Sort layers in QGIS table of contents?
When I load a bunch of layers into QGIS from PostGIS, they seem to load in reverse alphabetical order.
Is there any tools or plugins that allow you to quickly sort the QGIS TOC in a different order? ...
5
votes
1answer
98 views
How to convert PostGis Table (Grid data) to Continuous field using Qgis?
I'd like to transform my Gridded Layer (generated form a PostGIS table of points) to a continuous and colored layer. How could I do this with Qgis or any other program?
Many thanks and best regards,
...
5
votes
1answer
227 views
QGIS or Postgis - How to split polylines with a point layer?
In QGIS, I would like to split the polylines in a layer loaded in the workspace with the points in another loaded layer. If a point intersects a polyline, this polyline should be transformed into two ...
5
votes
1answer
362 views
Export each layer in map to a separate image
I have a mxd file with multiple layers I have to export to PNG/JPG. I would like to create a script which turns on layers one at the time before they are exported. So far I have come up with the ...
5
votes
1answer
80 views
Load third-party APIs only when the corresponding map layer is requested?
OpenLayers allows multiple map layers to be hosted on a common platform. If the map application supports a wide variety of maps, say from Google, Yahoo and Microsoft, I find that upon initialization, ...
5
votes
3answers
127 views
Automating an ArcGIS Project that is a display of map
I'm relatively new to GIS and looking to automate a project. I have my 'base map' created in ArcGIS, but now need to create several hundred more so looking for an automated method to accomplish this. ...
4
votes
3answers
2k views
Change Icon of Single Vector Feature in Layer
Currently I am trying to change the icon of a particular feature of a vector layer that the user is focusing on. I add each feature to the map like so:
var point = new ...
4
votes
1answer
147 views
Extracting donut holes as separate layer in QGIS
Does anyone know how I can extract the holes in a polygon layer as a separate layer in Quantum GIS? An example could be a country with a number of lakes cut out of the polygon - I need the lakes.
I ...
4
votes
2answers
338 views
How to copy a group of layers between QGIS projects?
In ArcGIS I am used to being able to have a couple of MXD documents open and copy-paste groups of layers from one MXD's table of contents to another. This can save a LOT of time ensuring consistent ...
4
votes
2answers
96 views
GIS projection for non-geographic data
I am working on two different types of data. One is related to mapping of Genome structure and another is creating a layout of the inventories inside Internet Data Center.
What I am confused about is ...
4
votes
1answer
597 views
Leaflet: How to move the layer-control menu?
This might be a silly question, but I could not find a documented way to achieve this.
I'd like to freely position the layer-control menu, probably to the top left near the default zoom-in/out ...
4
votes
1answer
326 views
Can QGIS preserve layers?
I saw this posted about a year ago (Can QGIS preserve layers when exporting to PDF?) but figured it was worth asking again -- is this possible? My usual workflow with ArcGIS is to export to AI then ...
4
votes
0answers
41 views
How to add layer with arcpy and retain description and other 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 ...
3
votes
1answer
242 views
What open-source web mapping solution I need to use for this situation?
I will try to explain what I need to do. I have about thirty KML polygons. I need to put them on some satellite map. On the top of these layers (KMLs, satellite) there must go layer with roads. I ...
3
votes
1answer
329 views
Can I change properties of several layers simultaneously?
I'm working on bulk data. I have a few hundred GeoTIFF images imported into a QGIS project, and I'd like to modify their layer properties - things like the no-data-value, transparency of certain pixel ...
3
votes
2answers
88 views
Unable to turn a layer off in ArcGIS 9.3.1
I was called over to try and fix an issue with a coworkers ArcGIS software (ArcView 9.3.1 SP1, Windows 7) and couldn't fix it. When a certain layer is turned off in the table of contents it never ...
3
votes
1answer
295 views
How to add a layer file to an ArcGIS map document programmatically?
I want to create a feature layer from a layer (.lyr) file and add it to my ArcGIS map document programmatically. I am using C# and ArcGIS.
I have a layer file and a shapefile.
3
votes
2answers
54 views
Where to look for oceanographical/environmental data for the Arctic (Baffin Bay/Davis Strait area)
I am looking for oceanographical/environmental variables that are available for Baffin Bay/Davis Strait area over the time period of 1995-2011, however, I am not familiar with ...
3
votes
1answer
287 views
How to hide some parts of an image layer with OpenLayers?
My Problem
I'm currently displaying a layer image above a Google Maps base layer. I would like, when the user check/uncheck some checkboxes, that some parts of this image layer disappear, and the ...
3
votes
2answers
93 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 ...
3
votes
2answers
418 views
Create multiple vector layers by reading a GeoJSON file once in OpenLayers
I am a begginner to OpenLayers, and my question is about making things more efficient.
My work is about displaying time-dependent weather elements on several point locations on the map. All these ...
3
votes
3answers
162 views
Why does the layer list context menu not open anymore?
I cannot access layers properties (i.e. change color, filter by query, anything).
The mouse right click doesn't do anything.
Is there a way restoring qgis to default?
Ubuntu 12.04, QGIS 1.8
3
votes
1answer
173 views
List Elements or Datasets of a given Layer
I am sorry of this might sound like a noob question but I cannot find any answer from google.
I used arcpy to do batch processing of Network Analyst - Make Service Area layer of thousand of stores.
...
3
votes
1answer
335 views
is it possible to convert 9.3 lyr to 10 lyr
I have a customer who sent me a lyr file in 9.3 and I am using 10, is there a way to import it in. It seems to hang up whenever I attempt to open it!
Thanks
3
votes
1answer
57 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 ...
3
votes
2answers
783 views
Load layers only when zoom level is reached
I'm trying to load different layers based on the user zoom level with OpenLayers. I've seen some similar questions in here, but they load the layer and then hide/show it based on the zoom level.
I ...
3
votes
2answers
312 views
Unable to select Vector Layer
I am using the following example, to select a vector layer feature on click. The example demonstrates Highlighting and selecting the layer. I was able to successfully implement the Highlighting of the ...
3
votes
1answer
182 views
Repairing disconnected layers with selection sets
Has anyone had any success of repairing disconnected layers that have selection sets that have their data sources broken in ArcGIS? Is there a way to detect this through code and then re-create that ...
2
votes
5answers
1k views
vector layer co-ordinate extraction QGIS
I add my own road vector data on top of Google map using open layers plugin with QGIS. The vector layer is generated using PostgreSQL DB.
Is there any way to extract co-ordinates of a road segment ?
...
2
votes
3answers
2k views
How to get the layer name?
I am using OpenLayers, Geoserver 2.1 CQL language. The problem is that I do not know how to address the layer. I am trying to call a function like this:
var createWmsLayer = function(name, url, ...
2
votes
2answers
1k views
Creating new layer from selection in Quantum-GIS
I have been using ArcMap for the last three years. But I am now considering switching to Quantum-GIS. Is it possible to create layers from selection in Q-GIS?
I am using QGIS 1.7.4-Wroclaw.
I will ...
2
votes
2answers
164 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.
...
2
votes
1answer
86 views
Is there easy way to get layers names from WMS server?
I've been looking for information on how to get layers names from certain WMS servers, but I didn't find any.
E.g. I have this server: http://sdi.geoportal.gov.pl/wms_prg/wmservice.aspx and I want to ...
2
votes
1answer
90 views
How to add Checkboxes in Geoserver
I have a POI table with some data of categories like Airport,ATM,Bank etc. I want to show these categories as checkbox so that if I click in the ATM Checkbox, only the ATM Points will be display. Is ...
2
votes
1answer
508 views
OGR and DXF files: Is it possible to handle layer names? (only “entities”)
I'm using Python and OGR to extract the layers of a DXF file and convert them into SHP.
I began with:
import ogr, os, sys
driver = ogr.GetDriverByName('DXF')
datasource = driver.Open('test1.dxf', 0)
...
2
votes
1answer
132 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
149 views
How to use arcpy.mapping to batch export layer to KML?
I am trying to export map layers from an MXD to KML using arcpy with the following code:
import arcpy, os, sys, traceback
arcpy.env.overwriteOutput = True
mxd = ...
2
votes
1answer
201 views
Make Feature Layer tool problems in Model Builder
I am having a slight problem with using the Make Feature Layer tool in model builder.
Basically I have a file geodatabase of points. I am trying to make a model to pull out points according to a ...
2
votes
1answer
297 views
Changing the name of layer using python
I am attempting to change the name of the layer. The following code changes the name of the layer but then removes the layer from the map, and I am not sure why.
Note: I don't have any remove layer ...
2
votes
1answer
394 views
How to have a layer with many images that scale?
I know that in OpenLayers you can add Features to a Vector Layer which each have image but then they will not scale (i.e. their size stays the same independent of the current zoom) or at least I do ...
2
votes
2answers
676 views
Why am I unable to publish a postgis layer to geoserver?
I left arcgis and microsoft sql and now I am trying to connect Qgis+PostgreSQL (PostGIS) + GeoServer.
I've brought my postgis database to the server, created a "store". And now I'm trying to publish ...
2
votes
1answer
48 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 ...
2
votes
2answers
128 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 ...
2
votes
1answer
471 views
How to set up a layer control using Leaflet?
I have been working on a mapping application using Leaflet. I am using a WMS on Geoserver to get my layers, which are overlaid on a cloudmade basemap.
I tried to use the layer control on my map by ...
2
votes
1answer
523 views
Create new polygon layers from postcodes latitude & longitude
First at all, I want to say that I am geocoding enthusiastic but have no formal background on GIS. I'll do my best to use the right wording and make myself clear what I am striving for.
Also the only ...
2
votes
1answer
141 views
Openlayers - Get Type of Layer
Is there a way to get the type of all the layers in an OpenLayer maps object? What I am trying to do is iterate over all the layers in my OpenLayers map object and populate a dropdown list with the ...
