windows - QGIS not coming to foreground

I recently upgraded from QGIS 3.2 to 3.4 using the standalone installer (Windows 64 bit), and uninstalling 3.2 beforehand. When I open 3.4 it goes the background behind all my other open programs and clicking its icon on the taskbar does nothing, nor does Alt-Tab. To use QGIS I have to minimize all my other open programs.

Is this a Windows issue, a QGIS issue, or something else entirely?

ogr2ogr - Converting shapefile from Shift_JIS to UTF-8 when the usual methods fail

Long story short, I'm trying to import this ESRI shapefile of Japan into CartoDB. (Sorry, no direct link: to download, click on the orange ファイルのダウンロード button, check 同意する to agree to the T&C, then click on the green 全国市区町村界データのダウンロード button.)

Problem is, the DBF in the file is encoded as Shift_JIS, and CartoDB only likes UTF-8. I've tried the following unsuccessfully:

1) ogr2ogr

ogr2ogr --config SHAPE_ENCODING Shift_JIS japan_ver72_utf8.shp 

No-op: SJIS in, SJIS out.

ogr2ogr --config SHAPE_ENCODING UTF-8 japan_ver72_utf8 japan_ver72.shp

Makes ogr2ogr think the input is UTF-8, meaning I get garbage out.

2) QGIS

Load the shapefile into QGIS as ShiftJIS. But while the shapes load fine, QGIS dumps a whole bunch of this on load:

ERROR 1: fread(48623) failed on DBF file.

And inspecting the attribute table just shows a bunch of nulls, so there's no point trying to save as UTF-8.

3) OpenOffice Calc

Load the DBF into OpenOffice, re-export as SJIS. But OO throws an error when parsing the DBF and refuses to import the file at all.

4) iconv

Run iconv directly on the DBF:

iconv -f Shift_JIS -t UTF-8 japan_ver72_sjis.dbf >japan_ver72.dbf

This "works", in the sense that the Japanese within is correctly recoded as UTF-8, but it destroys the DBF in the process.

Ideas?

Answer

If you only need to do the job once and there is no need to go to scripting then one simple way is to convert the data with OpenJUMP.

Activate the charactes set selection from menu Customize - Options

Open your dataset as Shift-JIS

Save data back with Save as... and select UTF-8 charset

merge - Connect points from two SpatialPointsDataFrames in R, considering the closest distance

I have two SpatialPointsDataFrames. In SpatialPointsDataFrame one (dat1) I have three points (A, B and C). In SpatialPointsDataFrame two (dat2), I have eight points with temperature measurements. I must connect each of those eight points to the closest point from dat1 and then calculate the average temperature for each point. How can I do that in R?

library(sp)
library(tmap)

# SpatialPointsDataFrame 1
dat_orig <- read.table(text="
point   lat   lng
A   15.6  80.9
B   20.9  10.9
C   1.2   81.8", header=TRUE, stringsAsFactors=FALSE)


dat1 <- dat_orig
coordinates(dat1) <- ~lng+lat

# SpatialPointsDataFrame 2
dat2_orig <- read.table(text = 
"temp   lat   lng
18   15.6  81.9
18.5   19.9  10.9
12.3   11.2   81.8
14.2   15.6  85.9

13.1   1.2  60.9
18.5   20.8  40.9
17   14.6  10.9
18.1   14.6  11.9", header=TRUE, stringsAsFactors=FALSE)

dat2 <- dat2_orig
coordinates(dat2) <- ~lng+lat

# tmap plot
tm_shape(dat1, ylim = c(-10, 35), xlim = c(-10,100)) + tm_dots(col = "red", size = 0.2) + tm_text("point") +

  tm_shape(dat2) + tm_dots(size = 0.1)

Answer

Use the FNN package:

> library(FNN)

this computes the first-nearest neighbours from dat1 for each of dat2:

> nn1 = get.knnx(coordinates(dat1), coordinates(dat2), 1)

The index into the three elements of dat1 for the 8 rows of dat2 is:

> ii = nn1$nn.index[,1]

> ii
[1] 1 2 1 1 3 2 2 2

(You can also get the distance out from nn1$nn.dist)

So we can then average the properties of dat2 grouped by that index with tapply:

> tapply(dat2$temp, list(ii), mean)
       1        2        3 
14.83333 18.02500 13.10000 

python - TKinter to provide variables

I've been looking for a way to enter a unique field name into an attribute table for up to 40 feature classes. I need the field names to be meaningful, not just 'field1', 'field2' etc. For example, if the feature class represents wetlands I would like a field called 'Wetland'.

I thought the easiest way of doing this would be to use TKinter. I can print the feature class name and then dynamically enter a field name with the TKinter data entry msgbox. Then keep looping through the feature classes until they all have a field with a unique name.

I've found some examples but am unsure about how to use data entry text as a variable in Python. If anyone out there had an example script or can make suggestions on this script I'd appreciate it:

import arcpy
from arcpy import env
from Tkinter import *

# Environment Workspace
env.workspace = r'G:\TEST\Python_Test\Test.gdb'


def receive():
    text = E1.get()
    print (text)
top = Tk()
L1 = Label(top, text="User Name")
L1.pack( side = LEFT)
E1 = Entry(top, bd =5)
E1.pack(side = RIGHT)
b = Button(top, text="OK", width=10, command=receive)

b.pack()
top.mainloop()

Answer

I managed to figure this out... My code now iterates through feature classes, requests a field name, calculates fields, deletes unwanted fields. And then joins the left over fields to each other with a spatial join. I was stuck on adding the interactive tkinter dialog box in the first loop, and the delete field text at the end of the first loop. I still have some to do on this, but thought I'd post the answers to my original question. Thought I'd put my code up for others:

import Tkinter
import tkSimpleDialog
import arcpy
from arcpy import env

env.workspace = r'G:\TEST\Python_Test\Test.gdb\env'


fcList = arcpy.ListFeatureClasses()

for fc in fcList:
    print fc
    root = Tkinter.Tk()
    var = tkSimpleDialog.askstring("Field Name", "Enter Field Name")
    print var

    arcpy.AddField_management(fc, var, "TEXT", "", "", "50", "", "NULLABLE", "REQUIRED", "")

    print "Adding field name " + var + " to " + fc
    arcpy.CalculateField_management(fc, var, "\"Y\"", "PYTHON", "")
    print "Calculating field " + var + " to " + fc

    keep = ['OBJECTID', 'Shape', 'Tower', var, 'Shape_Area', 'Shape_Length']

    discard = []
    for field in [f.name for f in arcpy.ListFields(fc)if f.type <> 'OBJECTID']:
        if field not in keep:
            discard.append(field)

    arcpy.DeleteField_management(fc, discard)
    print "Deleted all fields except those specified"

# Input variables for spatial join
Buffer1 = r'G:\Test\Python_Test\Test.gdb\Buffer1'
Buffer2 = r'G:\Test\Python_Test\Test.gdb\Buffer2'

sjList = arcpy.ListFeatureClasses()

# For loop for spatial join process


for sj in sjList:

    # Spatial join between buffered points and feature
    arcpy.SpatialJoin_analysis(Buffer1, sj, Buffer2, "JOIN_ONE_TO_ONE", "KEEP_ALL")
    print "Completed spatial join " + sj

    # Delete Buffer1 containing no joined features
    arcpy.Delete_management(Buffer1, "FeatureClass")
    print "deleted Buffer1 " + sj


    # Copies Buffer2 containing joined features and outputs as Buffer1
    arcpy.Copy_management(Buffer2, Buffer1, "")
    print "Copied Buffer2 to Buffer1 "  + sj

    # Deletes Buffer2 to allow script to create Buffer2 in next iteration
    arcpy.Delete_management(Buffer2, "FeatureClass")
    print "Deleted Buffer2 "  + sj

arcobjects - Error opening feature class from SDE (which can be opened in another application)

We're using ArcGIS 10.1 with ArcSDE 9.3.1 on Oracle 10g.

I've got two layers that cannot be opened or modified with ArcCatalog or ArcMap (but they show up in the list. Everything worked just fine until a few days ago when I added some columns from a third party software using SQL. As if this wasn't foolish enough (as it seems on Google) I also had an MXD open with these layers in it.

Now I can't open or use them in any ArcEnviroment of any kind (also tried Topocad and FME, and on different computers, one of them has ArcGIS 9.3.1... No go). Mostly I only get "Error opening feature class". Sometimes when I try to open the properties of the layers I get "Failed to edit the selected object(s). The workspace is not connected. Table attachments not supported in this release of the Geodatabase.". I've also gotten "Arcobjects error -2147216117 - Network I/O error".

The third party application however, can open and use them just fine, although it's reading from a view consisting of the data table + geometry table (the "F****"-tables) for each respective layer. With this in mind I've checked the database. Both the data tables and geometry tables exist with no errors and the connection between them is registered. I read somewhere on Google that the SDE.COLUMN_REGISTRY table could get out of sync when adding columns via SQL. So I checked it, but it's in sync. I also checked some metadata tables but couldn't see anything there (I don't really know what I'm looking for in there though).

My best guess is that the problem lies somewhere "between" ArcGIS and the database, since the tables obviously exists and is working in the third party application. There's no network error either since the rest of the database layers and tables can be used just fine. I'm guessing the problem lies in some kind of registry, metadata tables or cache, but I'm getting all out of ideas.

edit: I forgot to mention that the tables are not versioned, and we tried a server reboot.

Anyone have any ideas?

javascript - List all columns of a dataset?

Using CARTO VL.

Having a dataset, is there a way to fetch all columns this dataset has before I create the viz object so I can programmatically decide which variables to add to the viz?

Something like:

const source = new carto.source.Dataset('my-dataset');
const columns = source.getColumns();

Slider for non time attributes in QGIS

How to filter data on attributes with a slider?

By example, i would like to filter weights (CHARGE in my layer) attribute for polygons without to change the filter formula.

The feature is available for time window. I don't know other solutions for non date/time type attributes.

How can i do?

qgis - How can i delete multiple nodes, for a polygon, with Quantum GIS?

I know how to select a single node and delete it. I can also click-drag to select MULTIPLE nodes. But if i click delete, only one node (from the higlighted list) is removed.

Can I delete all the highlighted nodes?

UPDATE:

Here's a quick YouTube clip, showing how it's not working. U can see that when I select 2 or 3 nodes, only ONE is deleted.

Answer

That was a bug #5657 that was fixed already in master.

arcgis 10.1 - Using ArcPy FieldMappings for Spatial Join?

I'm trying to create a python script tool to use within ArcMap 10.1. I created a Model and exported it as a python script and added custom field mappings for the first Spatial Join by reading through others' example scripts, however, the resulting fields when the script is run don't join using the "; " delimiter, and the output fields are the same as the input. I currently run the script as a python tool in ArcMap 10.1.

I'm stumped at this point even after reading all articles from ESRI on the FieldMappings object and its methods. The script is as follows if anyone would like to take a look:

import arcpy

# Script arguments

Waterbodies_UTM13_20130228 = arcpy.GetParameterAsText(0)

MT_ESA_20131023 = arcpy.GetParameterAsText(1)

wbdhu8_a_mt = arcpy.GetParameterAsText(2)

Montana_Soils__2_ = arcpy.GetParameterAsText(3)

WB_HUC_Intersect_ESA_UTM13_M1 = arcpy.GetParameterAsText(4)



# Local variables:
Waterbodies_UTM13_20130228__2_ = Waterbodies_UTM13_20130228
Waterbodies_or_Wetlands_on_ESA = Waterbodies_UTM13_20130228__2_
WL_WB_Joined_with_HUC_Basins_Data = Waterbodies_or_Wetlands_on_ESA
Biological_ESA_MT_Intersect = WL_WB_Joined_with_HUC_Basins_Data
Biological_ESA_MT_Intersect_ = Biological_ESA_MT_Intersect


# Process: Select Layer By Attribute: Selects all USACE = "Yes" features

arcpy.SelectLayerByAttribute_management(Waterbodies_UTM13_20130228, "NEW_SELECTION", "\"USACE\" = 'Yes'")

# Process: Select Layer By Location: Selects all features from the USACE = "Yes" features that intersect the ESA
arcpy.SelectLayerByLocation_management(Waterbodies_UTM13_20130228__2_, "INTERSECT", MT_ESA_20131023, "", "SUBSET_SELECTION")


# FieldMappings for Spatial Join process: Create a new "fieldmappings" and add the join features' attribute table
fieldmappings = arcpy.FieldMappings()
fieldmappings.addTable(Waterbodies_UTM13_20130228)
fieldmappings.addTable(wbdhu8_a_mt)


# FieldMappings for Spatial Join process: Get the fields maps for the fields: REGION, SUBREGION, BASIN, and SUBBASIN
RegionFieldIndex = fieldmappings.findFieldMapIndex("REGION")
fieldmap1 = fieldmappings.getFieldMap(RegionFieldIndex)

SubRegionFieldIndex = fieldmappings.findFieldMapIndex("SUBREGION")
fieldmap2 = fieldmappings.getFieldMap(SubRegionFieldIndex)

BasinFieldIndex = fieldmappings.findFieldMapIndex("BASIN")
fieldmap3 = fieldmappings.getFieldMap(BasinFieldIndex)


SubBasinFieldIndex = fieldmappings.findFieldMapIndex("SUBBASIN")
fieldmap4 = fieldmappings.getFieldMap(SubBasinFieldIndex)

# FieldMappings for Spatial Join process: Set output fields and allowed field length to max (255)
field1 = fieldmap1.outputField
field2 = fieldmap2.outputField
field3 = fieldmap3.outputField
field4 = fieldmap4.outputField


field1.length = "255"
field2.length = "255"
field3.length = "255"
field4.length = "255"

fieldmap1.outputField = field1
fieldmap2.outputField = field2
fieldmap3.outputField = field3
fieldmap4.outputField = field4


# FieldMappings for Spatial Join process: Set the merge rule to join using the "; " delimiter and replace the old fieldmaps for each of the fields in the mappings object with updated one
fieldmap1.mergeRule = "Join"
fieldmap1.joinDelimiter = "; "
fieldmappings.replaceFieldMap(RegionFieldIndex, fieldmap1)

fieldmap2.mergeRule = "Join"
fieldmap2.joinDelimiter = "; "
fieldmappings.replaceFieldMap(SubRegionFieldIndex, fieldmap2)

fieldmap3.mergeRule = "Join"

fieldmap3.joinDelimiter = "; "
fieldmappings.replaceFieldMap(BasinFieldIndex, fieldmap3)

fieldmap4.mergeRule = "Join"
fieldmap4.joinDelimiter = "; "
fieldmappings.replaceFieldMap(SubBasinFieldIndex, fieldmap4)


# Process: Spatial Join: Spatially joins the HUC Basins data to the target WL or WB features (attributes are not "joined"; if a WB or WL falls on more than one basin,
# fieldmappings will concatenate attributes from select fields using "; " as a delimiter

arcpy.SpatialJoin_analysis(Waterbodies_or_Wetlands_on_ESA, wbdhu8_a_mt, WL_WB_Joined_with_HUC_Basins_Data, "JOIN_ONE_TO_ONE", "KEEP_ALL", fieldmappings, "INTERSECT")

# Process: Intersect: Intersects the temp output file from Spatial Join containing the joined WB or WL with the ESA, to create WL or WB pieces within the ESA
arcpy.Intersect_analysis([WL_WB_Joined_with_HUC_Basins_Data, MT_ESA_20131023], Biological_ESA_MT_Intersect, "ALL", "", "INPUT")

# Process: Multipart To Singlepart: Explodes all WL or WB pieces into singlepart features
arcpy.MultipartToSinglepart_management(Biological_ESA_MT_Intersect, Biological_ESA_MT_Intersect_)

# Process: Spatial Join (2): Spatially joins the exploded WL or WB features containing the HUC basins data with the Soils Data; attributes ARE "joined" and
# use "; " to deliminate all attributes from features that intersect the WL or WB features

arcpy.SpatialJoin_analysis(Biological_ESA_MT_Intersect_, Montana_Soils__2_, WB_HUC_Intersect_ESA_UTM13_M1, "JOIN_ONE_TO_ONE", "KEEP_ALL", "", "INTERSECT", "", "")

Screenshot of the error window in ArcMap:

Line 95:

arcpy.SpatialJoin_analysis(Waterbodies_or_Wetlands_on_ESA, wbdhu8_a_mt, WL_WB_Joined_with_HUC_Basins_Data, "JOIN_ONE_TO_ONE", "KEEP_ALL", fieldmappings, "INTERSECT")

Reducing Land Cover Data Sets in Earth Engine

I am trying to use earth engine to reduce the USGS land cover dataset and calculate the frequency of specific land cover types in several regions. The output that I am getting creates a single dictionary with a list of land cover types and values for each county (region).

I am curious if I can break this dictionary up to allow a table to be exported to google drive with each land cover type having a unique column?

Here is my code:

// Load a FeatureCollection of Maine Counties.

var Counties = ee.FeatureCollection('ft:1S4EB6319wWW2sWQDPhDvmSBIVrD3iEmCLYB7nMM').filter(ee.Filter.eq('StateName', 'Maine'));

//Imports NLCD Land Cover Data
var LandCover2011 = ee.Image('USGS/NLCD/NLCD2011')

// Clip the image to the polygon geometry
var LandCover2011 = LandCover2011.clip(Counties);

// Extract the landcover band
var landcover = LandCover2011.select('landcover');



// Print out the frequency of landcover occurrence for each county
var frequency = landcover.reduceRegions({
  collection: Counties,
  reducer:ee.Reducer.frequencyHistogram(),
  scale:30
});

//Prints Feature collection

print(frequency);

//Exports table to drive
//Export.table.toDrive(frequency, "MaineLandCoverData");

Answer

You can get the "histogram" property (resulting from the reducer) as a Dictionary which can be used to set the landcover:frequency pairs as new properties for a county feature. Then just map that function over all counties in the FeatureCollection.

// Print out the frequency of landcover occurrence for each county
//...

// Optional for debugging: Drop other properties and geometry > simpler looking csv.

frequency = frequency.select(['histogram'], null, false)

var frequency = frequency.map(function(feature){
  var dict = ee.Dictionary(feature.toDictionary().get('histogram'))
  feature = feature.set(dict)
  return feature
})
print('per class landcover frequency properties', frequency)

//Exports table to drive

Export.table.toDrive(frequency, "MaineLandCoverData");

Integrate GeoJSON file with openlayers.protocol.http

I've got a problem with (the title says it) integrating a geojson file in my openlayers map. I have to use the openlayers.protocol.http way. I examined lots of examples on the web (and on stackexchange) but I cannot figure out what the problem with my exact code is. it shows the layer in the layerswitcher, but it doesn't show the features.

I hope someone can find the error. Here's my code (relating geojson):

WebMapping - Übung 12

Ihr Browser unterstützt keine Inlineframes

Wikipedia-Integration in OpenLayers

pyqgis - QGIS 2.14 Python sub-menus

I'm trying to add sub-menu items to a menu that linked to a toolbar icon. It's probably best to show what result I'm getting currently, then reference the code:

The code is coming from a plugin class:

class SandBox2:

def __init__(self, iface):
    self.iface = iface
    self.plugin_dir = os.path.dirname(os.path.realpath(__file__))
    self.actions = []

def initGui(self):
    self.toolbar = self.iface.addToolBar("Sandbox2")
    self.toolbar.setObjectName("Sandbox2")


    self.SetupSubMenu = QAction((QIcon("C:/Users/Rudy/.qgis2/python/plugins/arcLensStandard/icons/new.png")), "Sub-Item 1-1",self.iface.mainWindow())
    self.submenu_11 = QMenu(self.iface.mainWindow()) 
    self.submenu_11.addAction(self.SetupSubMenu)
    self.SetupSubMenu.triggered.connect(self.runMsg1)

    self.SetupMainMenuItem = QAction((QIcon("C:/Users/Rudy/.qgis2/python/plugins/arcLensStandard/icons/item_one.png")), "First Menu Item", self.iface.mainWindow())
    self.Menu1 = QMenu(self.iface.mainWindow())
    self.Menu1.addAction(self.SetupMainMenuItem)
    self.Menu1.addMenu(self.submenu_11)


    self.toolButton = QToolButton()
    self.toolButton.setIcon(QIcon("C:/Users/Rudy/.qgis2/python/plugins/arcLensStandard/icons/adddata.png"))
    self.toolButton.setMenu(self.Menu1)
    self.toolButton.setPopupMode(QToolButton.InstantPopup)
    self.toolbar.addWidget(self.toolButton)

def runMsg1(self):
    QMessageBox.information(self.iface.mainWindow(), "Message", 
        "Sub-Item 1-1 Message", QMessageBox.Ok)

What I want to see is the right-facing caret symbol on the same line as the "First Menu Item" string, instead of appearing on a blank line after the string. The statement that's adding the sub-menu is:

self.Menu1.addMenu(self.submenu_11)

and that's where the blank line gets inserted (apparently).

Answer

You can assign a name to Menu1 (e.g. first_menu) and then call this when adding your action for your submenu:

def initGui(self):
    self.toolbar = self.iface.addToolBar("Sandbox2")
    self.toolbar.setObjectName("Sandbox2")


    self.SetupSubMenu = QAction((QIcon("C:/Users/Rudy/.qgis2/python/plugins/arcLensStandard/icons/new.png")), "Sub-Item 1-1",self.iface.mainWindow())
    self.SetupSubMenu.triggered.connect(self.runMsg1)

    self.Menu1 = QMenu(self.iface.mainWindow())
    # Here we assign the name for the first menu
    first_menu = self.Menu1.addMenu(QIcon("C:/Users/Rudy/.qgis2/python/plugins/arcLensStandard/icons/item_one.png"), "First Menu Item")
    # Call first_menu to add the action for the submenu
    first_menu.addAction(self.SetupSubMenu)

    self.toolButton = QToolButton()

    self.toolButton.setIcon(QIcon("C:/Users/Rudy/.qgis2/python/plugins/arcLensStandard/icons/adddata.png"))
    self.toolButton.setMenu(self.Menu1)
    self.toolButton.setPopupMode(QToolButton.InstantPopup)
    self.toolbar.addWidget(self.toolButton)

arcgis desktop - Sequential IDs with field calculator: Pad a prefixed field to specific length

I have an ID field that is a text datatype. The IDs in the field have a prefix, and are padded with zeros to always be a specific length. Examples:

• INSP000098


• INSP000099


• INSP000100


• INSP000101

I would like to use the Field Calculator to generate sequential IDs for new records (records are batch loaded from various sources by the thousands).

I have a python script that almost does this:

Modified from: Create sequential numbers in a field using Python in the Field Calculator

prefix = "INSP0000"
lastnumber=97

rec=0
def autoIncrement(): 
 global rec 
 pStart = 1  

 pInterval = 1 
 if (rec == 0):  
  rec = 1 + lastnumber
 else:  
  rec += pInterval 
 return prefix+str(rec)

---

autoIncrement()

Steps:

1. Manually enter the prefix (with zeros for padding)


2. Manually enter the last number in the existing IDs


3. Run the script

Result:

Unfortunately, the tool isn't smart enough to dynamically adjust for the difference in the number of digits between numbers (99 to 100, etc.):

• INSP000098



• INSP000099


• INSP0000100 << Problem: too many zeros/digits


• INSP0000101

How can I use the field calculator to generate sequential, prefixed IDs that are padded with zeros to a specific length?

I'm not married to Python; VBScript would be an acceptable alternative.

Answer

rec=97
def withPads():
 global rec

 rec+=1
 return 'INSP%s' %str(rec).zfill(6)
#------------
withPads()

OUTPUT:

arcgis desktop - Exporting a timeslice from a Netcdf-Rasterlayer as tif-rasterlayer

In ArcGIS Desktop 10.4 (advanced licence) I downloaded a NetCDF-File from here: http://eca.knmi.nl/download/ensembles/downloadchunks.php (the 0.25 grid with the years 1995-2016). It consists of temperature-data over time (in days).

I read it into ArcGIS as a NetCDF-Rasterlayer, and now I'm trying to export data of a single time-slice as a tif-rasterlayer. I did not get the hang on Mosaic Datasets, so my plan is to make a spatial analysis on the exported tif-rasterlayer, relating it to landuse (also in a tif-rasterlayer), and later aggregating it to NUTS3-Level). If I keep track what happens to which rasters I can later export other time-slices as tables and relate the spatial analysis to them.

The export-function (Data->Export) works in principle, but the raster looses it's attribute table, and without that I can't keep track which cell relates to which.

Does anyone have a suggestion on how to get that working?

coordinate system - Quick way to determine if facing a given lat/lon pair with a heading

I'm looking for a fast way, preferably without trigonometric operations (just multiply, divide, add, sqrt and subtract) to determine if a point is visible. E.g. say I am facing 0 degrees N, I am at 51.40,-1.08, the camera has a HFOV of 30 degrees and the point is at 51.20,-1.085 it should return TRUE, because the point would be facing me and is within the 30 degree FOV.

It's required that it returns TRUE (false positive) instead of FALSE given edge cases, otherwise points may be hidden when they are actually visible. Currently I have my augmented reality project using atan2 to calculate the actual angle but if I can shave calculations off from points which are definitely not visible every little bit helps. I only need it to be accurate over distances of less than 2 km.

Here's my code to calculate horizontal and vertical position. It's only accurate over <5km distances but accuracy isn't critical anyway as those waypoints aren't drawn. This project is open source, so it's okay for me to post a lot of code.

res->est_dist = hypot2(p_viewer->p.lat - p_subj->lat, p_viewer->p.lon - p_subj->lon) * 2000.0f;
// Save precious cycles if outside of visible world.
if(res->est_dist > cliph)
    goto quick_exit;
// Compute the horizontal and vertical angle to the point. 
res->h_angle = angle_dist_deg(RAD2DEG(atan2(p_viewer->p.lon - p_subj->lon, p_viewer->p.lat - p_subj->lat)), p_viewer->yaw);
res->v_angle = RAD2DEG(atan2(p_viewer->p.alt - p_subj->alt, res->est_dist)); // constant scale factor: needs to be adjusted
// Normalize the results to fit in the field of view of the camera.
res->h_angle += p_viewer->hfov / 2;

res->v_angle += p_viewer->vfov / 2;
// Compute projected X and Y position.
res->pos.x = (res->h_angle / p_viewer->hfov) * p_viewer->width;
res->pos.y = (res->v_angle / p_viewer->vfov) * p_viewer->height;

See that call to atan2 for the h_angle? If I could eliminate it by saying "this point is definitely not visible" it would be nice.