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.

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21
votes
5answers
11k views

What is difference between map layer and spatial dataset (e.g. feature class, shapefile)?

This may be very trivial question. To me they seems very similar in concept. What is the difference between feature class and feature layer?
9
votes
7answers
5k 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 ...
7
votes
1answer
1k 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? ...
14
votes
6answers
3k views

How to improve rendering performance of very large shapefile?

I have a polygon shapefile that has a 100MB .dbf and 500MB .shp file component. The reason it is so large is it is a landbase classification for a whole district. Everytime I am viewing the file in ...
2
votes
5answers
2k views

Is there any way to extract coordinates of a road segment using 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 coordinates of a road segment ?
5
votes
1answer
1k 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 ...
2
votes
1answer
1k 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 ...
1
vote
3answers
4k views

Merging Two or More Layers

I am working with three clipped layers that are shown in the TOC. I created these layers from a large watershed shape-file. However, each clipped layer includes the layer before it and only expands on ...
3
votes
2answers
2k 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 ...
2
votes
1answer
510 views

QGIS identify features button issue

Is there anyway to get the Identify Features button in QGIS to automatically select a layer and provide the information without having to highlight it first in the layers TOC? MapInfo and ArcGIS ...
5
votes
1answer
1k 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 ...
3
votes
1answer
206 views

Show alternating contour lines

Is it possible to show only every other counture line? And how do you do that? (Im new to QGIS Lisboa 1.8.0, but even newer to QGIS Dufour 2.0.1, but have used ArcGIS a bit a while ago, and also ...
3
votes
1answer
3k 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 ...
3
votes
1answer
2k views

XYZ Layer in Open Layers has Missing Tiles

In Open Layers I'm having a missing tile problem where it generates a missing link icon and a pink background. I found several threads including this one saying to add this code ...
1
vote
2answers
84 views

Open mail client when clicking feature in Attribute Table

One of the attributes/features of my layer contains an email address. I'd like to be able to open the default mail client by clicking on the mail address from the Attribute Table. After some initial ...
3
votes
1answer
73 views

what dictates the drawing order of overlapping features with in the same layer/feature class in ArcGIS?

I know that in ArcGIS drawing order is controlled by layers, and if I want to make some features be drawn on top of other features I can use definition queries to separate them into different layers ...
3
votes
1answer
212 views

How to replace the legacy function “doQueries ” to AMD ESRI Javascript format?

I'm trying to understand the migration of ESRI API for javascript, from legacy to AMD. In the case of this example, how replace the fucntion doqueries????: function init() { map = new ...
3
votes
1answer
276 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. ...
2
votes
1answer
124 views

Why is shapefile not drawing in expected location after (or before) using Define Projection tool? [duplicate]

I have downloaded this zipped shapefile of bus routes from the City of Houston data portal. I then performed these steps in ArcGIS Desktop 9.3.1: Extracted the shapefile from the *.zip Added this ...
2
votes
1answer
924 views

Add AutoCAD .dwg annotation file to Arcmap using python (Same as +ADD Data button)

I would like to add an AutoCad .dwg file to Arcmap using python the same way that the +ADD Data button does. I can add an Annotation layer with python but only as a feature layer not as an annotation ...
2
votes
2answers
1k views

How to remove layers of detail from an osm file?

I want to remove some layers from the osm map of an area. It has all the details like POI, offline routing and all. But I just want the map data. How can I remove this extra layer from the map?
1
vote
1answer
21 views

Legend hangs with large featurelayers at startup

My problem is that I created an app with a lot of services that the user can use. The problem is that when I implement the legend widget and the code goes over startup(), the app becomes stuck and it ...
1
vote
1answer
73 views

How do I programatically edit the layer 'Display Expression'

I'm wondering if someone has or knows where a tool is to edit the 'Display Expression' of a Layer, or more specifically, a TableView, in ArcGIS Desktop. I know that it can't be accessed with Python, ...
1
vote
1answer
61 views

Overlap or intersect two choropleth [closed]

I have two choropleth of the same area but with different concentration data and I need to overlap them. My aim is to highlight the areas of intersection between the points with the highest ...
1
vote
1answer
612 views

Applying layer file not formating labels in ARCGIS 10

I'm applying layer files in ARCGIS 10 using the ApplySymbologyFromLayer_management command via a python script tool. The symbology part works fine but the lables are not formatting. It is my ...
0
votes
0answers
37 views

Missing Raster/Vector Layers after converting KMZ using KMLToLayer tool of ArcGIS Desktop?

I am trying to write a tool that will let users upload a KML/KMZ file and then be able to view it in a client application (something like an esri js api or Flex app). I am ok with storing the data in ...
0
votes
1answer
346 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
1answer
2k views

How to Obtain the feature attributes from feature collection

I am able to obtain the features of the layer which is selected by the user in the Layers table and then intersected by a user defined polygon, using e.features. I was able to obtain the attribute ...